## SPICE User's Guide |
## Table of Contents |

INTRODUCTION | CIRCUIT ELEMENTS AND MODELS | INTERACTIVE INTERPRETER | APPENDIX A |

CIRCUIT DESCRIPTION | ANALYSES AND OUTPUT CONTROL | BIBLIOGRAPHY | APPENDIX B |

1.INTRODUCTION

SPICE is a general-purpose circuit simulation program for nonlinear dc, nonlinear transient, and linear ac ana- lyses. Circuits may contain resistors, capacitors, induc- tors, mutual inductors, independent voltage and current sources, four types of dependent sources, lossless and lossy transmission lines (two separate implementations), switches, uniform distributed RC lines, and the five most common sem- iconductor devices: diodes, BJTs, JFETs, MESFETs, and MOS- FETs.

The SPICE3 version is based directly on SPICE 2G.6. While SPICE3 is being developed to include new features, it continues to support those capabilities and models which remain in extensive use in the SPICE2 program.

SPICE has built-in models for the semiconductor dev- ices, and the user need specify only the pertinent model parameter values. The model for the BJT is based on the integral-charge model of Gummel and Poon; however, if the Gummel- Poon parameters are not specified, the model reduces to the simpler Ebers-Moll model. In either case, charge- storage effects, ohmic resistances, and a current-dependent output conductance may be included. The diode model can be used for either junction diodes or Schottky barrier diodes. The JFET model is based on the FET model of Shichman and Hodges. Six MOSFET models are implemented: MOS1 is described by a square-law I-V characteristic, MOS2 [1] is an analytical model, while MOS3 [1] is a semi-empirical model; MOS6 [2] is a simple analytic model accurate in the short- channel region; MOS4 [3, 4] and MOS5 [5] are the BSIM (Berkeley Short-channel IGFET Model) and BSIM2. MOS2, MOS3, and MOS4 include second-order effects such as channel-length modulation, subthreshold conduction, scattering-limited velocity saturation, small-size effects, and charge- controlled capacitances.

TYPES OF ANALYSIS | ANALYSIS AT DIFFERENT TEMPERATURES | CONVERGENCE |

1.1.TYPESOFANALYSIS

DC Analysis | Transient Analysis | SmallSignal Distortion Analysis | Noise Analysis |

AC SmallSignal Analysis | PoleZero Analysis | Sensitivity Analysis |

1.1.1.DCAnalysis

The dc analysis portion of SPICE determines the dc operating point of the circuit with inductors shorted and capacitors opened. The dc analysis options are specified on the .DC, .TF, and .OP control lines. A dc analysis is automatically performed prior to a transient analysis to determine the transient initial conditions, and prior to an ac small-signal analysis to determine the linearized, small-signal models for nonlinear devices. If requested, the dc small-signal value of a transfer function (ratio of output variable to input source), input resistance, and out- put resistance is also computed as a part of the dc solu- tion. The dc analysis can also be used to generate dc transfer curves: a specified independent voltage or current source is stepped over a user-specified range and the dc output variables are stored for each sequential source value.

1.1.2.ACSmall-SignalAnalysis

The ac small-signal portion of SPICE computes the ac output variables as a function of frequency. The program first computes the dc operating point of the circuit and determines linearized, small-signal models for all of the nonlinear devices in the circuit. The resultant linear cir- cuit is then analyzed over a user-specified range of fre- quencies. The desired output of an ac small- signal analysis is usually a transfer function (voltage gain, tran- simpedance, etc). If the circuit has only one ac input, it is convenient to set that input to unity and zero phase, so that output variables have the same value as the transfer function of the output variable with respect to the input.

1.1.3.TransientAnalysis

The transient analysis portion of SPICE computes the transient output variables as a function of time over a user-specified time interval. The initial conditions are automatically determined by a dc analysis. All sources which are not time dependent (for example, power supplies) are set to their dc value. The transient time interval is specified on a .TRAN control line.

1.1.4.Pole-ZeroAnalysis

The pole-zero analysis portion of SPICE computes the poles and/or zeros in the small-signal ac transfer function. The program first computes the dc operating point and then determines the linearized, small-signal models for all the nonlinear devices in the circuit. This circuit is then used to find the poles and zeros of the transfer function.

Two types of transfer functions are allowed : one of the form (output voltage)/(input voltage) and the other of the form (output voltage)/(input current). These two types of transfer functions cover all the cases and one can find the poles/zeros of functions like input/output impedance and voltage gain. The input and output ports are specified as two pairs of nodes.

The pole-zero analysis works with resistors, capaci- tors, inductors, linear-controlled sources, independent sources, BJTs, MOSFETs, JFETs and diodes. Transmission lines are not supported.

The method used in the analysis is a sub-optimal numer- ical search. For large circuits it may take a considerable time or fail to find all poles and zeros. For some cir- cuits, the method becomes "lost" and finds an excessive number of poles or zeros.

1.1.5.Small-SignalDistortionAnalysis

The distortion analysis portion of SPICE computes steady-state harmonic and intermodulation products for small input signal magnitudes. If signals of a single frequency are specified as the input to the circuit, the complex values of the second and third harmonics are determined at every point in the circuit. If there are signals of two frequencies input to the circuit, the analysis finds out the complex values of the circuit variables at the sum and difference of the input frequencies, and at the difference of the smaller frequency from the second harmonic of the larger frequency.

Distortion analysis is supported for the following non- linear devices: diodes (DIO), BJT, JFET, MOSFETs (levels 1, 2, 3, 4/BSIM1, 5/BSIM2, and 6) and MESFETS. All linear dev- ices are automatically supported by distortion analysis. If there are switches present in the circuit, the analysis con- tinues to be accurate provided the switches do not change state under the small excitations used for distortion calcu- lations.

1.1.6.SensitivityAnalysis

Spice3 will calculate either the DC operating-point sensitivity or the AC small-signal sensitivity of an output variable with respect to all circuit variables, including model parameters. Spice calculates the difference in an output variable (either a node voltage or a branch current) by perturbing each parameter of each device independently. Since the method is a numerical approximation, the results may demonstrate second order affects in highly sensitive parameters, or may fail to show very low but non-zero sensi- tivity. Further, since each variable is perturb by a small fraction of its value, zero-valued parameters are not analy- ized (this has the benefit of reducing what is usually a very large amount of data).

1.1.7.NoiseAnalysis

The noise analysis portion of SPICE does analysis device-generated noise for the given circuit. When provided with an input source and an output port, the analysis calcu- lates the noise contributions of each device (and each noise generator within the device) to the output port voltage. It also calculates the input noise to the circuit, equivalent to the output noise referred to the specified input source. This is done for every frequency point in a specified range - the calculated value of the noise corresponds to the spec- tral density of the circuit variable viewed as a stationary gaussian stochastic process.

After calculating the spectral densities, noise analysis integrates these values over the specified fre- quency range to arrive at the total noise voltage/current (over this frequency range). This calculated value corresponds to the variance of the circuit variable viewed as a stationary gaussian process.

1.2.ANALYSISATDIFFERENTTEMPERATURES

All input data for SPICE is assumed to have been meas- o ured at a nominal temperature of 27 C, which can be changed by use of the TNOM parameter on the .OPTION control line. This value can further be overridden for any device which models temperature effects by specifying the TNOM parameter on the model itself. The circuit simulation is performed at o a temperature of 27 C, unless overridden by a TEMP parameter on the .OPTION control line. Individual instances may further override the circuit temperature through the specif- ication of a TEMP parameter on the instance.

Temperature dependent support is provided for resis- tors, diodes, JFETs, BJTs, and level 1, 2, and 3 MOSFETs. BSIM (levels 4 and 5) MOSFETs have an alternate temperature dependency scheme which adjusts all of the model parameters before input to SPICE. For details of the BSIM temperature adjustment, see [6] and [7].

Temperature appears explicitly in the exponential terms of the BJT and diode model equations. In addition, satura- tion currents have a built-in temperature dependence. The temperature dependence of the saturation current in the BJT models is determined by:

XTI |T | | E q(T T )| 1 g 1 0 I (T ) = I (T ) |--| exp|-----------| S 1 S 0 |T | |k (T - T )| 0 1 0

where k is Boltzmann's constant, q is the electronic charge, E is the energy gap which is a model parameter, G and XTI is the saturation current temperature exponent (also a model parameter, and usually equal to 3).

The temperature dependence of forward and reverse beta is according to the formula:

XTB |T | 1 B(T ) = B(T ) |--| 1 0 |T | 0

where T and T are in degrees Kelvin, and XTB is a 1 0 user-supplied model parameter. Temperature effects on beta are carried out by appropriate adjustment to the values of B , I , B , and I (spice model parameters F SE R SC BF, ISE, BR, and ISC, respectively).

Temperature dependence of the saturation current in the junction diode model is determined by:

XTI --- N |T | | E q(T T ) | 1 g 1 0 I (T ) = I (T ) |--| exp|-------------| S 1 S 0 |T | |N k (T - T )| 0 1 0

where N is the emission coefficient, which is a model parameter, and the other symbols have the same meaning as above. Note that for Schottky barrier diodes, the value of the saturation current temperature exponent, XTI, is usually 2.

Temperature appears explicitly in the value of junction potential, U (in spice PHI), for all the device models. The temperature dependence is determined by:

| N N | a d kT |------ | U(T) = -- log 2 q e |N (T) | i

where k is Boltzmann's constant, q is the electronic charge, N is the acceptor impurity density, N is the a d donor impurity density, N is the intrinsic carrier con- i centration, and E is the energy gap. g

Temperature appears explicitly in the value of surface mobility, M (or UO), for the MOSFET model. The temperature 0 dependence is determined by:

M (T ) 0 0 M (T) = ------- 0 1.5 | T| |--| |T | 0

The effects of temperature on resistors is modeled by the formula:

2 R(T) = R(T ) [1 + TC (T - T ) + TC (T - T ) ] 0 1 0 2 0

where T is the circuit temperature, T is the nominal 0 temperature, and TC and TC are the first- and second- 1 2 order temperature coefficients.

1.3.CONVERGENCE

Both dc and transient solutions are obtained by an iterative process which is terminated when both of the fol- lowing conditions hold:

1) The nonlinear branch currents converge to within a tolerance of 0.1% or 1 picoamp (1.0e-12 Amp), whichever is larger.

2) The node voltages converge to within a tolerance of 0.1% or 1 microvolt (1.0e-6 Volt), whichever is larger.

Although the algorithm used in SPICE has been found to be very reliable, in some cases it fails to converge to a solution. When this failure occurs, the program terminates the job.

Failure to converge in dc analysis is usually due to an error in specifying circuit connections, element values, or model parameter values. Regenerative switching circuits or circuits with positive feedback probably will not converge in the dc analysis unless the OFF option is used for some of the devices in the feedback path, or the .NODESET control line is used to force the circuit to converge to the desired state.

2.CIRCUITDESCRIPTION

GENERAL STRUCTURE AND CONVENTIONS | DEVICE MODELS | COMBINING FILES | |

TITLE LINE COMMENT LINES AND .END LINE | SUBCIRCUITS |

2.1.GENERALSTRUCTUREANDCONVENTIONS

The circuit to be analyzed is described to SPICE by a set of element lines, which define the circuit topology and element values, and a set of control lines, which define the model parameters and the run controls. The first line in the input file must be the title, and the last line must be ".END". The order of the remaining lines is arbitrary (except, of course, that continuation lines must immediately follow the line being continued).

Each element in the circuit is specified by an element line that contains the element name, the circuit nodes to which the element is connected, and the values of the param- eters that determine the electrical characteristics of the element. The first letter of the element name specifies the element type. The format for the SPICE element types is given in what follows. The strings XXXXXXX, YYYYYYY, and ZZZZZZZ denote arbitrary alphanumeric strings. For example, a resistor name must begin with the letter R and can contain one or more characters. Hence, R, R1, RSE, ROUT, and R3AC2ZY are valid resistor names. Details of each type of device are supplied in a following section.

Fields on a line are separated by one or more blanks, a comma, an equal ('=') sign, or a left or right parenthesis; extra spaces are ignored. A line may be continued by enter- ing a '+' (plus) in column 1 of the following line; SPICE continues reading beginning with column 2.

A name field must begin with a letter (A through Z) and cannot contain any delimiters.

A number field may be an integer field (12, -44), a floating point field (3.14159), either an integer or float- ing point number followed by an integer exponent (1e-14, 2.65e3), or either an integer or a floating point number followed by one of the following scale factors:

12 9 6 3 -6 T = 10 G = 10 Meg = 10 K = 10 mil = 25.4 -3 -6 -9 -12 -15 m = 10 u (or M) = 10 n = 10 p = 10 f = 10

Letters immediately following a number that are not scale factors are ignored, and letters immediately following a scale factor are ignored. Hence, 10, 10V, 10Volts, and 10Hz all represent the same number, and M, MA, MSec, and MMhos all represent the same scale factor. Note that 1000, 1000.0, 1000Hz, 1e3, 1.0e3, 1KHz, and 1K all represent the same number.

Nodes names may be arbitrary character strings. The datum (ground) node must be named '0'. Note the difference in SPICE3 where the nodes are treated as character strings and not evaluated as numbers, thus '0' and '00' are distinct nodes in SPICE3 but not in SPICE2. The circuit cannot con- tain a loop of voltage sources and/or inductors and cannot contain a cut-set of current sources and/or capacitors. Each node in the circuit must have a dc path to ground. Every node must have at least two connections except for transmission line nodes (to permit unterminated transmission lines) and MOSFET substrate nodes (which have two internal connections anyway).

2.2.TITLELINE,COMMENTLINESAND.ENDLINE

Title Line | .END Line | Comments |

2.2.1.TitleLine

Examples:

POWER AMPLIFIER CIRCUIT TEST OF CAM CELL

The title line must be the first in the input file. Its contents are printed verbatim as the heading for each section of output.

2.2.2. .ENDLine

Examples:

.END

The "End" line must always be the last in the input file. Note that the period is an integral part of the name.

2.2.3.Comments

GeneralForm:

* <any comment>

Examples:

* RF=1K Gain should be 100 * Check open-loop gain and phase margin

The asterisk in the first column indicates that this line is a comment line. Comment lines may be placed anywhere in the circuit description. Note that SPICE3 also considers any line with leading white space to be a comment.

2.3.DEVICEMODELS

Generalform:

.MODEL MNAME TYPE(PNAME1=PVAL1 PNAME2=PVAL2 ... )

Examples:

.MODEL MOD1 NPN (BF=50 IS=1E-13 VBF=50)

Most simple circuit elements typically require only a few parameter values. However, some devices (semiconductor devices in particular) that are included in SPICE require many parameter values. Often, many devices in a circuit are defined by the same set of device model parameters. For these reasons, a set of device model parameters is defined on a separate .MODEL line and assigned a unique model name. The device element lines in SPICE then refer to the model name.

For these more complex device types, each device ele- ment line contains the device name, the nodes to which the device is connected, and the device model name. In addi- tion, other optional parameters may be specified for some devices: geometric factors and an initial condition (see the following section on Transistors and Diodes for more de- tails).

MNAME in the above is the model name, and type is one of the following fifteen types:

R Semiconductor resistor model C Semiconductor capacitor model SW Voltage controlled switch CSW Current controlled switch URC Uniform distributed RC model LTRA Lossy transmission line model D Diode model NPN NPN BJT model PNP PNP BJT model NJF N-channel JFET model PJF P-channel JFET model NMOS N-channel MOSFET model PMOS P-channel MOSFET model NMF N-channel MESFET model PMF P-channel MESFET model

Parameter values are defined by appending the parameter name followed by an equal sign and the parameter value. Model parameters that are not given a value are assigned the default values given below for each model type. Models, model parameters, and default values are listed in the next section along with the description of device element lines.

2.4.SUBCIRCUITS

A subcircuit that consists of SPICE elements can be defined and referenced in a fashion similar to device models. The subcircuit is defined in the input file by a grouping of element lines; the program then automatically inserts the group of elements wherever the subcircuit is referenced. There is no limit on the size or complexity of subcircuits, and subcircuits may contain other subcircuits. An example of subcircuit usage is given in Appendix A.

.SUBCKT Line | .ENDS Line | Subcircuit Calls |

2.4.1. .SUBCKTLine

Generalform:

.SUBCKT subnam N1 <N2 N3 ...>

Examples:

.SUBCKT OPAMP 1 2 3 4

A circuit definition is begun with a .SUBCKT line. SUBNAM is the subcircuit name, and N1, N2, ... are the external nodes, which cannot be zero. The group of element lines which immediately follow the .SUBCKT line define the subcircuit. The last line in a subcircuit definition is the .ENDS line (see below). Control lines may not appear within a subcircuit definition; however, subcircuit definitions may contain anything else, including other subcircuit defin- itions, device models, and subcircuit calls (see below). Note that any device models or subcircuit definitions included as part of a subcircuit definition are strictly local (i.e., such models and definitions are not known out- side the subcircuit definition). Also, any element nodes not included on the .SUBCKT line are strictly local, with the exception of 0 (ground) which is always global.

2.4.2. .ENDSLine

Generalform:

.ENDS <SUBNAM>

Examples:

.ENDS OPAMP

The "Ends" line must be the last one for any sub- circuit definition. The subcircuit name, if included, indicates which subcircuit definition is being terminat- ed; if omitted, all subcircuits being defined are ter- minated. The name is needed only when nested subcircuit definitions are being made.

2.4.3.SubcircuitCalls

Generalform:

XYYYYYYY N1 <N2 N3 ...> SUBNAM

Examples:

X1 2 4 17 3 1 MULTI

Subcircuits are used in SPICE by specifying pseudo-elements beginning with the letter X, followed by the circuit nodes to be used in expanding the subcir- cuit.

2.5.COMBININGFILES: .INCLUDELINES

Generalform:

.INCLUDEfilename

Examples:

.INCLUDE /users/spice/common/wattmeter.cir

Frequently, portions of circuit descriptions will be reused in several input files, particularly with common models and subcircuits. In any spice input file, the ".include" line may be used to copy some other file as if that second file appeared in place of the ".include" line in the original file. There is no restriction on the file name imposed by spice beyond those imposed by the local operating system.

3.CIRCUITELEMENTSANDMODELS

Data fields that are enclosed in less-than and greater-than signs ('< >') are optional. All indicated punctuation (parentheses, equal signs, etc.) is optional but indicate the presence of any delimiter. Further, future implementations may require the punctuation as stated. A consistent style adhering to the punctuation shown here makes the input easier to understand. With respect to branch voltages and currents, SPICE uniformly uses the asso- ciated reference convention (current flows in the direction of voltage drop).

ELEMENTARY DEVICES | VOLTAGE AND CURRENT SOURCES | TRANSMISSION LINES | TRANSISTORS AND DIODES |

3.1.ELEMENTARYDEVICES

Resistors | Capacitors | Inductors | Switch Model |

Semiconductor Resistors | Semiconductor Capacitors | Coupled Inductors | |

Semiconductor Resistor Model | Semiconductor Capacitor Model | Switches |

3.1.1.Resistors

Generalform:

RXXXXXXX N1 N2 VALUE

Examples:

R1 1 2 100 RC1 12 17 1K

N1 and N2 are the two element nodes. VALUE is the resistance (in ohms) and may be positive or negative but not zero.

3.1.2.SemiconductorResistors

Generalform:

RXXXXXXX N1 N2 <VALUE> <MNAME> <L=LENGTH> <W=WIDTH> <TEMP=T>

Examples:

RLOAD 2 10 10K RMOD 3 7 RMODEL L=10u W=1u

This is the more general form of the resistor presented in section 6.1, and allows the modeling of temperature effects and for the calculation of the actual resistance value from strictly geometric information and the specifica- tions of the process. If VALUE is specified, it overrides the geometric information and defines the resistance. If MNAME is specified, then the resistance may be calculated from the process information in the model MNAME and the given LENGTH and WIDTH. If VALUE is not specified, then MNAME and LENGTH must be specified. If WIDTH is not speci- fied, then it is taken from the default width given in the model. The (optional) TEMP value is the temperature at which this device is to operate, and overrides the tempera- ture specification on the .OPTION control line.

3.1.3.SemiconductorResistorModel(R)

The resistor model consists of process-related device data that allow the resistance to be calculated from geometric information and to be corrected for temperature. The parameters available are:

name parameter units default example

o TC1 first order temperature coeff. Z/ C 0.0 - o 2 TC2 second order temperature coeff. Z/ C 0.0 - RSH sheet resistance Z/[] - 50 DEFW default width meters 1e-6 2e-6 NARROW narrowing due to side etching meters 0.0 1e-7 o TNOM parameter measurement temperature C 27 50

The sheet resistance is used with the narrowing parame- ter and L and W from the resistor device to determine the nominal resistance by the formula

L - NARROW R = RSH ---------- W - NARROW

DEFW is used to supply a default value for W if one is not specified for the device. If either RSH or L is not speci- fied, then the standard default resistance value of 1k Z is used. TNOM is used to override the circuit-wide value given on the .OPTIONS control line where the parameters of this model have been measured at a different temperature. After the nominal resistance is calculated, it is adjusted for temperature by the formula:

2 R(T) = R(T ) [1 + TC1 (T - T ) + TC2 (T-T ) ] 0 0 0

3.1.4.Capacitors

Generalform:

CXXXXXXX N+ N- VALUE <IC=INCOND>

Examples:

CBYP 13 0 1UF COSC 17 23 10U IC=3V

N+ and N- are the positive and negative element nodes, respectively. VALUE is the capacitance in Farads.

The (optional) initial condition is the initial (time- zero) value of capacitor voltage (in Volts). Note that the initial conditions (if any) apply 'only' if the UIC option is specified on the .TRAN control line.

3.1.5.SemiconductorCapacitors

Generalform:

CXXXXXXX N1 N2 <VALUE> <MNAME> <L=LENGTH> <W=WIDTH> <IC=VAL>

Examples:

CLOAD 2 10 10P CMOD 3 7 CMODEL L=10u W=1u

This is the more general form of the Capacitor presented in section 6.2, and allows for the calculation of the actual capacitance value from strictly geometric infor- mation and the specifications of the process. If VALUE is specified, it defines the capacitance. If MNAME is speci- fied, then the capacitance is calculated from the process information in the model MNAME and the given LENGTH and WIDTH. If VALUE is not specified, then MNAME and LENGTH must be specified. If WIDTH is not specified, then it is taken from the default width given in the model. Either VALUE or MNAME, LENGTH, and WIDTH may be specified, but not both sets.

3.1.6.SemiconductorCapacitorModel(C)

The capacitor model contains process information that may be used to compute the capacitance from strictly geometric information.

name parameter units default example

2 CJ junction bottom capacitance F/meters - 5e-5 CJSW junction sidewall capacitance F/meters - 2e-11 DEFW default device width meters 1e-6 2e-6 NARROW narrowing due to side etching meters 0.0 1e-7

The capacitor has a capacitance computed as

CAP = CJ (LENGTH - NARROW) (WIDTH - NARROW) + 2 CJSW (LENGTH + WIDTH - 2 NARROW)

3.1.7.Inductors

Generalform:

LYYYYYYY N+ N- VALUE <IC=INCOND>

Examples:

LLINK 42 69 1UH LSHUNT 23 51 10U IC=15.7MA

N+ and N- are the positive and negative element nodes, respectively. VALUE is the inductance in Hen- ries.

The (optional) initial condition is the initial (time- zero) value of inductor current (in Amps) that flows from N+, through the inductor, to N-. Note that the initial con- ditions (if any) apply only if the UIC option is specified on the .TRAN analysis line.

3.1.8.Coupled(Mutual)Inductors

Generalform:

KXXXXXXX LYYYYYYY LZZZZZZZ VALUE

Examples:

K43 LAA LBB 0.999 KXFRMR L1 L2 0.87

LYYYYYYY and LZZZZZZZ are the names of the two cou- pled inductors, and VALUE is the coefficient of cou- pling, K, which must be greater than 0 and less than or equal to 1. Using the 'dot' convention, place a 'dot' on the first node of each inductor.

3.1.9.Switches

Generalform:

SXXXXXXX N+ N- NC+ NC- MODEL <ON><OFF> WYYYYYYY N+ N- VNAM MODEL <ON><OFF>

Examples:

s1 1 2 3 4 switch1 ON s2 5 6 3 0 sm2 off Switch1 1 2 10 0 smodel1 w1 1 2 vclock switchmod1 W2 3 0 vramp sm1 ON wreset 5 6 vclck lossyswitch OFF

Nodes 1 and 2 are the nodes between which the switch terminals are connected. The model name is man- datory while the initial conditions are optional. For the voltage controlled switch, nodes 3 and 4 are the po- sitive and negative controlling nodes respectively. For the current controlled switch, the controlling current is that through the specified voltage source. The direction of positive controlling current flow is from the positive node, through the source, to the negative node.

3.1.10.SwitchModel(SW/CSW)

The switch model allows an almost ideal switch to be described in SPICE. The switch is not quite ideal, in that the resistance can not change from 0 to infinity, but must always have a finite positive value. By proper selection of the on and off resistances, they can be effectively zero and infinity in comparison to other circuit elements. The parameters available are:

name parameter units default switch

VT threshold voltage Volts 0.0 S IT threshold current Amps 0.0 W VH hysteresis voltage Volts 0.0 S IH hysteresis current Amps 0.0 W RON on resistance Z 1.0 both ROFF off resistance Z 1/GMIN* both

*(See the .OPTIONS control line for a description of GMIN, its default value results in an off-resistance of 1.0e+12 ohms.)

The use of an ideal element that is highly nonlinear such as a switch can cause large discontinuities to occur in the circuit node voltages. A rapid change such as that associated with a switch changing state can cause numerical roundoff or tolerance problems leading to erroneous results or timestep difficulties. The user of switches can improve the situation by taking the following steps:

First, it is wise to set ideal switch impedances just high or low enough to be negligible with respect to other circuit elements. Using switch impedances that are close to "ideal" in all cases aggravates the problem of discontinui- ties mentioned above. Of course, when modeling real devices such as MOSFETS, the on resistance should be adjusted to a realistic level depending on the size of the device being modeled.

If a wide range of ON to OFF resistance must be used in the switches (ROFF/RON >1e+12), then the tolerance on errors allowed during transient analysis should be decreased by using the .OPTIONS control line and specifying TRTOL to be less than the default value of 7.0. When switches are placed around capacitors, then the option CHGTOL should also be reduced. Suggested values for these two options are 1.0 and 1e-16 respectively. These changes inform SPICE3 to be more careful around the switch points so that no errors are made due to the rapid change in the circuit.

3.2.VOLTAGEANDCURRENTSOURCES

Independent Sources | Linear Dependent Sources | Nonlinear Dependent Sources |

3.2.1.IndependentSources

Generalform:

VXXXXXXX N+ N- <<DC> DC/TRAN VALUE> <AC <ACMAG <ACPHASE>>> + <DISTOF1 <F1MAG <F1PHASE>>> <DISTOF2 <F2MAG <F2PHASE>>> IYYYYYYY N+ N- <<DC> DC/TRAN VALUE> <AC <ACMAG <ACPHASE>>> + <DISTOF1 <F1MAG <F1PHASE>>> <DISTOF2 <F2MAG <F2PHASE>>>

Examples:

VCC 10 0 DC 6 VIN 13 2 0.001 AC 1 SIN(0 1 1MEG) ISRC 23 21 AC 0.333 45.0 SFFM(0 1 10K 5 1K) VMEAS 12 9 VCARRIER 1 0 DISTOF1 0.1 -90.0 VMODULATOR 2 0 DISTOF2 0.01 IIN1 1 5 AC 1 DISTOF1 DISTOF2 0.001

N+ and N- are the positive and negative nodes, respec- tively. Note that voltage sources need not be grounded. Positive current is assumed to flow from the positive node, through the source, to the negative node. A current source of positive value forces current to flow out of the N+ node, through the source, and into the N- node. Voltage sources, in addition to being used for circuit excitation, are the 'ammeters' for SPICE, that is, zero valued voltage sources may be inserted into the circuit for the purpose of measur- ing current. They of course have no effect on circuit operation since they represent short-circuits.

DC/TRAN is the dc and transient analysis value of the source. If the source value is zero both for dc and tran- sient analyses, this value may be omitted. If the source value is time-invariant (e.g., a power supply), then the value may optionally be preceded by the letters DC.

ACMAG is the ac magnitude and ACPHASE is the ac phase. The source is set to this value in the ac analysis. If ACMAG is omitted following the keyword AC, a value of unity is assumed. If ACPHASE is omitted, a value of zero is assumed. If the source is not an ac small-signal input, the keyword AC and the ac values are omitted.

DISTOF1 and DISTOF2 are the keywords that specify that the independent source has distortion inputs at the frequen- cies F1 and F2 respectively (see the description of the .DISTO control line). The keywords may be followed by an optional magnitude and phase. The default values of the magnitude and phase are 1.0 and 0.0 respectively.

Any independent source can be assigned a time-dependent value for transient analysis. If a source is assigned a time-dependent value, the time-zero value is used for dc analysis. There are five independent source functions: pulse, exponential, sinusoidal, piece-wise linear, and single-frequency FM. If parameters other than source values are omitted or set to zero, the default values shown are assumed. (TSTEP is the printing increment and TSTOP is the final time (see the .TRAN control line for explanation)).

Pulse | Exponential | SingleFrequency FM | |

Sinusoidal | PieceWise Linear |

3.2.1.1.Pulse

Generalform:

PULSE(V1 V2 TD TR TF PW PER)

Examples:

VIN 3 0 PULSE(-1 1 2NS 2NS 2NS 50NS 100NS)

parameter default value units ----------------------------------------------------- V1 (initial value) Volts or Amps V2 (pulsed value) Volts or Amps TD (delay time) 0.0 seconds TR (rise time) TSTEP seconds TF (fall time) TSTEP seconds PW (pulse width) TSTOP seconds PER(period) TSTOP seconds

A single pulse so specified is described by the follow- ing table:

time value ------------------- 0 V1 TD V1 TD+TR V2 TD+TR+PW V2 TD+TR+PW+TF V1 TSTOP V1

Intermediate points are determined by linear interpola- tion.

3.2.1.2.Sinusoidal

Generalform:

SIN(VO VA FREQ TD THETA)

Examples:

VIN 3 0 SIN(0 1 100MEG 1NS 1E10)

parameters default value units ------------------------------------------------------- VO (offset) Volts or Amps VA (amplitude) Volts or Amps FREQ (frequency) 1/TSTOP Hz TD (delay) 0.0 seconds THETA (damping factor) 0.0 1/seconds

The shape of the waveform is described by the following table:

time value ------------------------------------------------------------ 0 to TD VO -(t - TD)THETA TD to TSTOP VO + VA e sin(2 J FREQ (t + TD))

3.2.1.3.Exponential

GeneralForm:

EXP(V1 V2 TD1 TAU1 TD2 TAU2)

Examples:

VIN 3 0 EXP(-4 -1 2NS 30NS 60NS 40NS)

parameter default value units --------------------------------------------------------- V1 (initial value) Volts or Amps V2 (pulsed value) Volts or Amps TD1 (rise delay time) 0.0 seconds TAU1 (rise time constant) TSTEP seconds TD2 (fall delay time) TD1+TSTEP seconds TAU2 (fall time constant) TSTEP seconds

The shape of the waveform is described by the following table:

time value ---------------------------------------------------------------------------- 0 to TD1 V1 | ------------| TAU1 | -(t - TD1) | -(t - TD2) TD1 to TD2 V1 + (V2 - V1) 1 - e | ----------| | ----------| | TAU1 | | TAU2 | TD2 to TSTOP V1 + (V2 - V1) - e + (V1 - V2) 1 - e

3.2.1.4.Piece-WiseLinear

GeneralForm:

PWL(T1 V1 <T2 V2 T3 V3 T4 V4 ...>)

Examples:

VCLOCK 7 5 PWL(0 -7 10NS -7 11NS -3 17NS -3 18NS -7 50NS -7)

Each pair of values (Ti, Vi) specifies that the value of the source is Vi (in Volts or Amps) at time=Ti. The value of the source at intermediate values of time is deter- mined by using linear interpolation on the input values.

3.2.1.5.Single-FrequencyFM

GeneralForm:

SFFM(VO VA FC MDI FS)

Examples:

V1 12 0 SFFM(0 1M 20K 5 1K)

parameter default value units ------------------------------------------------------- VO (offset) Volts or Amps VA (amplitude) Volts or Amps FC (carrier frequency) 1/TSTOP Hz MDI (modulation index) FS (signal frequency) 1/TSTOP Hz

The shape of the waveform is described by the following equation:

| | V(t)=V + V sin 2 J FC t + MDI sin(2 J FS t) O A | |

3.2.2.LinearDependentSources

SPICE allows circuits to contain linear dependent sources characterized by any of the four equations

i = g v v = e v i = f i v = h i

where g, e, f, and h are constants representing transconduc- tance, voltage gain, current gain, and transresistance, respectively.

Linear VoltageControlled Current Sources | Linear VoltageControlled Voltage Sources | Linear CurrentControlled Current Sources | Linear CurrentControlled Voltage Sources |

3.2.2.1.LinearVoltage-ControlledCurrentSources

Generalform:

GXXXXXXX N+ N- NC+ NC- VALUE

Examples:

G1 2 0 5 0 0.1MMHO

N+ and N- are the positive and negative nodes, respectively. Current flow is from the positive node, through the source, to the negative node. NC+ and NC- are the positive and negative controlling nodes, respec- tively. VALUE is the transconductance (in mhos).

3.2.2.2.LinearVoltage-ControlledVoltageSources

Generalform:

EXXXXXXX N+ N- NC+ NC- VALUE

Examples:

E1 2 3 14 1 2.0

N+ is the positive node, and N- is the negative node. NC+ and NC- are the positive and negative con- trolling nodes, respectively. VALUE is the voltage gain.

3.2.2.3.LinearCurrent-ControlledCurrentSources

Generalform:

FXXXXXXX N+ N- VNAM VALUE

Examples:

F1 13 5 VSENS 5

N+ and N- are the positive and negative nodes, respectively. Current flow is from the positive node, through the source, to the negative node. VNAM is the name of a voltage source through which the controlling current flows. The direction of positive controlling current flow is from the positive node, through the source, to the negative node of VNAM. VALUE is the current gain.

3.2.2.4.LinearCurrent-ControlledVoltageSources

Generalform:

HXXXXXXX N+ N- VNAM VALUE

Examples:

HX 5 17 VZ 0.5K

N+ and N- are the positive and negative nodes, respectively. VNAM is the name of a voltage source through which the controlling current flows. The direc- tion of positive controlling current flow is from the positive node, through the source, to the negative node of VNAM. VALUE is the transresistance (in ohms).

3.2.3.Non-linearDependentSources

Generalform:

BXXXXXXX N+ N- <I=EXPR> <V=EXPR>

Examples:

B1 0 1 I=cos(v(1))+sin(v(2)) B1 0 1 V=ln(cos(log(v(1,2)^2)))-v(3)^4+v(2)^v(1) B1 3 4 I=17 B1 3 4 V=exp(pi^i(vdd))

N+ is the positive node, andN- is the negative node. The values of the V and I parameters determine the voltages and currents across and through the device, respectively. If I is given then the device is a current source, and if V is given the device is a voltage source. One and only one of these parameters must be given.

The small-signal AC behavior of the nonlinear source is a linear dependent source (or sources) with a proportional- ity constant equal to the derivative (or derivatives) of the source at the DC operating point.

The expressions given for V and I may be any function of voltages and currents through voltage sources in the sys- tem. The following functions of real variables are defined:

abs asinh cosh sin acos atan exp sinh acosh atanh ln sqrt asin cos log tan

The function "u" is the unit step function, with a value of one for arguments greater than one and a value of zero for arguments less than zero. The function "uramp" is the integral of the unit step: for an inputx, the value is zero ifxis less than zero, or ifxis greater than zero the value isx. These two functions are useful in sythesiz- ing piece-wise non-linear functions, though convergence may be adversely affected.

The following standard operators are defined:

+ - * / ^ unary -

If the argument of log, ln, or sqrt becomes less than zero, the absolute value of the argument is used. If a divisor becomes zero or the argument of log or ln becomes zero, an error will result. Other problems may occur when the argument for a function in a partial derivative enters a region where that function is undefined.

To get time into the expression you can integrate the current from a constant current source with a capacitor and use the resulting voltage (don't forget to set the initial voltage across the capacitor). Non-linear resistors, capa- citors, and inductors may be synthesized with the nonlinear dependent source. Non-linear resistors are obvious. Non- linear capacitors and inductors are implemented with their linear counterparts by a change of variables implemented with the nonlinear dependent source. The following subcir- cuit will implement a nonlinear capacitor:

.Subckt nlcap pos neg * Bx: calculate f(input voltage) Bx 1 0 v = f(v(pos,neg)) * Cx: linear capacitance Cx 2 0 1 * Vx: Ammeter to measure current into the capacitor Vx 2 1 DC 0Volts * Drive the current through Cx back into the circuit Fx pos neg Vx 1 .ends

Non-linear inductors are similar.

3.3.TRANSMISSIONLINES

Lossless Transmission Lines | Lossy Transmission Line Model | Uniform Distributed RC Model | |

Lossy Transmission Lines | Uniform Distributed RC Lines |

3.3.1.LosslessTransmissionLines

Generalform:

TXXXXXXX N1 N2 N3 N4 Z0=VALUE <TD=VALUE> <F=FREQ <NL=NRMLEN>> + <IC=V1, I1, V2, I2>

Examples:

T1 1 0 2 0 Z0=50 TD=10NS

N1 and N2 are the nodes at port 1; N3 and N4 are the nodes at port 2. Z0 is the characteristic impedance. The length of the line may be expressed in either of two forms. The transmission delay, TD, may be specified directly (as TD=10ns, for example). Alternatively, a frequency F may be given, together with NL, the normalized electrical length of the transmission line with respect to the wavelength in the line at the frequency F. If a frequency is specified but NL is omitted, 0.25 is assumed (that is, the frequency is assumed to be the quarter-wave frequency). Note that although both forms for expressing the line length are indi- cated as optional, one of the two must be specified.

Note that this element models only one propagating mode. If all four nodes are distinct in the actual circuit, then two modes may be excited. To simulate such a situa- tion, two transmission-line elements are required. (see the example in Appendix A for further clarification.)

The (optional) initial condition specification consists of the voltage and current at each of the transmission line ports. Note that the initial conditions (if any) apply 'only' if the UIC option is specified on the .TRAN control line.

Note that a lossy transmission line (see below) with zero loss may be more accurate than than the lossless transmission line due to implementation details.

3.3.2.LossyTransmissionLines

Generalform:

OXXXXXXX N1 N2 N3 N4 MNAME

Examples:

O23 1 0 2 0 LOSSYMOD OCONNECT 10 5 20 5 INTERCONNECT

This is a two-port convolution model for single- conductor lossy transmission lines. N1 and N2 are the nodes at port 1; N3 and N4 are the nodes at port 2. Note that a lossy transmission line with zero loss may be more accurate than than the lossless transmission line due to implementa- tion details.

3.3.3.LossyTransmissionLineModel(LTRA)

The uniform RLC/RC/LC/RG transmission line model (re- ferred to as the LTRA model henceforth) models a uniform constant-parameter distributed transmission line. The RC and LC cases may also be modeled using the URC and TRA models; however, the newer LTRA model is usually faster and more accurate than the others. The operation of the LTRA model is based on the convolution of the transmission line's impulse responses with its inputs (see [8]).

The LTRA model takes a number of parameters, some of which must be given and some of which are optional.

name parameter units/type default example

R resistance/length Z/unit 0.0 0.2 L inductance/length henrys/unit 0.0 9.13e-9 G conductance/length mhos/unit 0.0 0.0 C capacitance/length farads/unit 0.0 3.65e-12 LEN length of line no default 1.0 REL breakpoint control arbitrary unit 1 0.5 ABS breakpoint control 1 5 NOSTEPLIMIT don't limit timestep to less than flag not set set line delay NOCONTROL don't do complex timestep control flag not set set LININTERP use linear interpolation flag not set set MIXEDINTERP use linear when quadratic seems bad not set set COMPACTREL special reltol for history compaction flag RELTOL 1.0e-3 COMPACTABS special abstol for history compaction ABSTOL 1.0e-9 TRUNCNR use Newton-Raphson method for flag not set set timestep control TRUNCDONTCUT don't limit timestep to keep flag not set set impulse-response errors low

The following types of lines have been implemented so far: RLC (uniform transmission line with series loss only), RC (uniform RC line), LC (lossless transmission line), and RG (distributed series resistance and parallel conductance only). Any other combination will yield erroneous results and should not be tried. The length LEN of the line must be specified.

NOSTEPLIMIT is a flag that will remove the default res- triction of limiting time-steps to less than the line delay in the RLC case. NOCONTROL is a flag that prevents the default limiting of the time-step based on convolution error criteria in the RLC and RC cases. This speeds up simulation but may in some cases reduce the accuracy of results. LININTERP is a flag that, when specified, will use linear interpolation instead of the default quadratic interpolation for calculating delayed signals. MIXEDINTERP is a flag that, when specified, uses a metric for judging whether qua- dratic interpolation is not applicable and if so uses linear interpolation; otherwise it uses the default quadratic interpolation. TRUNCDONTCUT is a flag that removes the default cutting of the time-step to limit errors in the actual calculation of impulse-response related quantities. COMPACTREL and COMPACTABS are quantities that control the compaction of the past history of values stored for convolu- tion. Larger values of these lower accuracy but usually increase simulation speed. These are to be used with the TRYTOCOMPACT option, described in the .OPTIONS section. TRUNCNR is a flag that turns on the use of Newton-Raphson iterations to determine an appropriate timestep in the timestep control routines. The default is a trial and error procedure by cutting the previous timestep in half. REL and ABS are quantities that control the setting of breakpoints.

The option most worth experimenting with for increasing the speed of simulation is REL. The default value of 1 is usually safe from the point of view of accuracy but occa- sionally increases computation time. A value greater than 2 eliminates all breakpoints and may be worth trying depending on the nature of the rest of the circuit, keeping in mind that it might not be safe from the viewpoint of accuracy. Breakpoints may usually be entirely eliminated if it is expected the circuit will not display sharp discontinuities. Values between 0 and 1 are usually not required but may be used for setting many breakpoints.

COMPACTREL may also be experimented with when the option TRYTOCOMPACT is specified in a .OPTIONS card. The legal range is between 0 and 1. Larger values usually decrease the accuracy of the simulation but in some cases improve speed. If TRYTOCOMPACT is not specified on a .OPTIONS card, history compaction is not attempted and accu- racy is high. NOCONTROL, TRUNCDONTCUT and NOSTEPLIMIT also tend to increase speed at the expense of accuracy.

3.3.4.UniformDistributedRCLines(Lossy)

Generalform:

UXXXXXXX N1 N2 N3 MNAME L=LEN <N=LUMPS>

Examples:

U1 1 2 0 URCMOD L=50U URC2 1 12 2 UMODL l=1MIL N=6

N1 and N2 are the two element nodes the RC line con- nects, while N3 is the node to which the capacitances are connected. MNAME is the model name, LEN is the length of the RC line in meters. LUMPS, if specified, is the number of lumped segments to use in modeling the RC line (see the model description for the action taken if this parameter is omitted).

3.3.5.UniformDistributedRCModel(URC)

The URC model is derived from a model proposed by L. Gertzberrg in 1974. The model is accomplished by a subcir- cuit type expansion of the URC line into a network of lumped RC segments with internally generated nodes. The RC seg- ments are in a geometric progression, increasing toward the middle of the URC line, with K as a proportionality con- stant. The number of lumped segments used, if not specified for the URC line device, is determined by the following for- mula: 2 | R C |(K-1)| | _ _ 2 log|F 2 J L |-----| | max | L L | K | |

N = ------------------------------ log K

The URC line is made up strictly of resistor and capa- citor segments unless the ISPERL parameter is given a non- zero value, in which case the capacitors are replaced with reverse biased diodes with a zero-bias junction capacitance equivalent to the capacitance replaced, and with a satura- tion current of ISPERL amps per meter of transmission line and an optional series resistance equivalent to RSPERL ohms per meter.

name parameter units default example area

1 K Propagation Constant - 2.0 1.2 - 2 FMAX Maximum Frequency of interest Hz 1.0G 6.5Meg - 3 RPERL Resistance per unit length Z/m 1000 10 - 4 CPERL Capacitance per unit length F/m 1.0e-15 1pF - 5 ISPERL Saturation Current per unit length A/m 0 - - 6 RSPERL Diode Resistance per unit length Z/m 0 - -

3.4.TRANSISTORSANDDIODES

The area factor used on the diode, BJT, JFET, and MES- FET devices determines the number of equivalent parallel devices of a specified model. The affected parameters are marked with an asterisk under the heading 'area' in the model descriptions below. Several geometric factors associ- ated with the channel and the drain and source diffusions can be specified on the MOSFET device line.

Two different forms of initial conditions may be speci- fied for some devices. The first form is included to improve the dc convergence for circuits that contain more than one stable state. If a device is specified OFF, the dc operating point is determined with the terminal voltages for that device set to zero. After convergence is obtained, the program continues to iterate to obtain the exact value for the terminal voltages. If a circuit has more than one dc stable state, the OFF option can be used to force the solu- tion to correspond to a desired state. If a device is specified OFF when in reality the device is conducting, the program still obtains the correct solution (assuming the solutions converge) but more iterations are required since the program must independently converge to two separate solutions. The .NODESET control line serves a similar pur- pose as the OFF option. The .NODESET option is easier to apply and is the preferred means to aid convergence.

The second form of initial conditions are specified for use with the transient analysis. These are true 'initial conditions' as opposed to the convergence aids above. See the description of the .IC control line and the .TRAN con- trol line for a detailed explanation of initial conditions.

Junction Diodes | BJT Models | MOSFETs | MESFET Models |

Diode Model | Junction FieldEffect Transistors | MOSFET Models | |

Bipolar Junction Transistors | JFET Models | MESFETs |

3.4.1.JunctionDiodes

Generalform:

DXXXXXXX N+ N- MNAME <AREA> <OFF> <IC=VD> <TEMP=T>

Examples:

DBRIDGE 2 10 DIODE1 DCLMP 3 7 DMOD 3.0 IC=0.2

N+ and N- are the positive and negative nodes, respec- tively. MNAME is the model name, AREA is the area factor, and OFF indicates an (optional) starting condition on the device for dc analysis. If the area factor is omitted, a value of 1.0 is assumed. The (optional) initial condition specification using IC=VD is intended for use with the UIC option on the .TRAN control line, when a transient analysis is desired starting from other than the quiescent operating point. The (optional) TEMP value is the temperature at which this device is to operate, and overrides the tempera- ture specification on the .OPTION control line.

3.4.2.DiodeModel(D)

The dc characteristics of the diode are determined by the parameters IS and N. An ohmic resistance, RS, is in- cluded. Charge storage effects are modeled by a transit time, TT, and a nonlinear depletion layer capacitance which is determined by the parameters CJO, VJ, and M. The tem- perature dependence of the saturation current is defined by the parameters EG, the energy and XTI, the saturation current temperature exponent. The nominal temperature at which these parameters were measured is TNOM, which defaults to the circuit-wide value specified on the .OPTIONS control line. Reverse breakdown is modeled by an exponential in- crease in the reverse diode current and is determined by the parameters BV and IBV (both of which are positive numbers).

name parameter units default example area

1 IS saturation current A 1.0e-14 1.0e-14 * 2 RS ohmic resistance Z 0 10 * 3 N emission coefficient - 1 1.0 4 TT transit-time sec 0 0.1ns 5 CJO zero-bias junction capacitance F 0 2pF * 6 VJ junction potential V 1 0.6 7 M grading coefficient - 0.5 0.5 8 EG activation energy eV 1.11 1.11 Si 0.69 Sbd 0.67 Ge 9 XTI saturation-current temp. exp - 3.0 3.0 jn 2.0 Sbd 10 KF flicker noise coefficient - 0 11 AF flicker noise exponent - 1 12 FC coefficient for forward-bias - 0.5 depletion capacitance formula 13 BV reverse breakdown voltage V infinite 40.0 14 IBV current at breakdown voltage A 1.0e-3 o 15 TNOM parameter measurement temperature C 27 50

3.4.3.BipolarJunctionTransistors(BJTs)

Generalform:

QXXXXXXX NC NB NE <NS> MNAME <AREA> <OFF> <IC=VBE, VCE> <TEMP=T>

Examples:

Q23 10 24 13 QMOD IC=0.6, 5.0 Q50A 11 26 4 20 MOD1

NC, NB, and NE are the collector, base, and emitter nodes, respectively. NS is the (optional) substrate node. If unspecified, ground is used. MNAME is the model name, AREA is the area factor, and OFF indicates an (optional) initial condition on the device for the dc analysis. If the area factor is omitted, a value of 1.0 is assumed. The (optional) initial condition specification using IC=VBE, VCE is intended for use with the UIC option on the .TRAN control line, when a transient analysis is desired starting from other than the quiescent operating point. See the .IC con- trol line description for a better way to set transient ini- tial conditions. The (optional) TEMP value is the tempera- ture at which this device is to operate, and overrides the temperature specification on the .OPTION control line.

3.4.4.BJTModels(NPN/PNP)

The bipolar junction transistor model in SPICE is an adaptation of the integral charge control model of Gummel and Poon. This modified Gummel-Poon model extends the ori- ginal model to include several effects at high bias levels. The model automatically simplifies to the simpler Ebers-Moll model when certain parameters are not specified. The param- eter names used in the modified Gummel-Poon model have been chosen to be more easily understood by the program user, and to reflect better both physical and circuit design thinking.

The dc model is defined by the parameters IS, BF, NF, ISE, IKF, and NE which determine the forward current gain characteristics, IS, BR, NR, ISC, IKR, and NC which deter- mine the reverse current gain characteristics, and VAF and VAR which determine the output conductance for forward and reverse regions. Three ohmic resistances RB, RC, and RE are included, where RB can be high current dependent. Base charge storage is modeled by forward and reverse transit times, TF and TR, the forward transit time TF being bias dependent if desired, and nonlinear depletion layer capaci- tances which are determined by CJE, VJE, and MJE for the B-E junction , CJC, VJC, and MJC for the B-C junction and CJS, VJS, and MJS for the C-S (Collector-Substrate) junction. The temperature dependence of the saturation current, IS, is determined by the energy-gap, EG, and the saturation current temperature exponent, XTI. Additionally base current tem- perature dependence is modeled by the beta temperature exponent XTB in the new model. The values specified are assumed to have been measured at the temperature TNOM, which can be specified on the .OPTIONS control line or overridden by a specification on the .MODEL line.

The BJT parameters used in the modified Gummel-Poon model are listed below. The parameter names used in earlier versions of SPICE2 are still accepted.

Modified Gummel-Poon BJT Parameters.

name parameter units default example area

1 IS transport saturation current A 1.0e-16 1.0e-15 * 2 BF ideal maximum forward beta - 100 100 3 NF forward current emission coefficient - 1.0 1 4 VAF forward Early voltage V infinite 200 5 IKF corner for forward beta high current roll-off A infinite 0.01 * 6 ISE B-E leakage saturation current A 0 1.0e-13 * 7 NE B-E leakage emission coefficient - 1.5 2 8 BR ideal maximum reverse beta - 1 0.1 9 NR reverse current emission coefficient - 1 1 10 VAR reverse Early voltage V infinite 200 11 IKR corner for reverse beta high current roll-off A infinite 0.01 * 12 ISC B-C leakage saturation current A 0 1.0e-13 * 13 NC B-C leakage emission coefficient - 2 1.5 14 RB zero bias base resistance Z 0 100 * 15 IRB current where base resistance falls halfway to its min value A infinite 0.1 * 16 RBM minimum base resistance at high currents Z RB 10 * 17 RE emitter resistance Z 0 1 * 18 RC collector resistance Z 0 10 * 19 CJE B-E zero-bias depletion capacitance F 0 2pF * 20 VJE B-E built-in potential V 0.75 0.6 21 MJE B-E junction exponential factor - 0.33 0.33 22 TF ideal forward transit time sec 0 0.1ns 23 XTF coefficient for bias dependence of TF - 0 24 VTF voltage describing VBC dependence of TF V infinite 25 ITF high-current parameter for effect on TF A 0 * 26 PTF excess phase at freq=1.0/(TF*2PI) Hz deg 0 27 CJC B-C zero-bias depletion capacitance F 0 2pF * 28 VJC B-C built-in potential V 0.75 0.5 29 MJC B-C junction exponential factor - 0.33 0.5 30 XCJC fraction of B-C depletion capacitance - 1 connected to internal base node 31 TR ideal reverse transit time sec 0 10ns 32 CJS zero-bias collector-substrate capacitance F 0 2pF * 33 VJS substrate junction built-in potential V 0.75 34 MJS substrate junction exponential factor - 0 0.5 35 XTB forward and reverse beta temperature exponent - 0 36 EG energy gap for temperature effect on IS eV 1.11 37 XTI temperature exponent for effect on IS - 3 38 KF flicker-noise coefficient - 0 39 AF flicker-noise exponent - 1 40 FC coefficient for forward-bias depletion capacitance formula - 0.5 o 41 TNOM Parameter measurement temperature C 27 50

3.4.5.JunctionField-EffectTransistors(JFETs)

Generalform:

JXXXXXXX ND NG NS MNAME <AREA> <OFF> <IC=VDS, VGS> <TEMP=T>

Examples:

J1 7 2 3 JM1 OFF

ND, NG, and NS are the drain, gate, and source nodes, respectively. MNAME is the model name, AREA is the area factor, and OFF indicates an (optional) initial condition on the device for dc analysis. If the area factor is omitted, a value of 1.0 is assumed. The (optional) initial condition specification, using IC=VDS, VGS is intended for use with the UIC option on the .TRAN control line, when a transient analysis is desired starting from other than the quiescent operating point. See the .IC control line for a better way to set initial conditions. The (optional) TEMP value is the temperature at which this device is to operate, and over- rides the temperature specification on the .OPTION control line.

3.4.6.JFETModels(NJF/PJF)

The JFET model is derived from the FET model of Shich- man and Hodges. The dc characteristics are defined by the parameters VTO and BETA, which determine the variation of drain current with gate voltage, LAMBDA, which determines the output conductance, and IS, the saturation current of the two gate junctions. Two ohmic resistances, RD and RS, are included. Charge storage is modeled by nonlinear deple- tion layer capacitances for both gate junctions which vary as the -1/2 power of junction voltage and are defined by the parameters CGS, CGD, and PB.

Note that in Spice3f and later, a fitting parameter B has been added. For details, see [9].

name parameter units default example area

1 VTO threshold voltage (V V -2.0 -2.0 TO 2 2 BETA transconductance parameter (B) A/V 1.0e-4 1.0e-3 * 3 LAMBDA channel-length modulation parameter (L) 1/V 0 1.0e-4 4 RD drain ohmic resistance Z 0 100 * 5 RS source ohmic resistance Z 0 100 * 6 CGS zero-bias G-S junction capacitance (C ) F 0 5pF * gs 7 CGD zero-bias G-D junction capacitance (C ) F 0 1pF * gs 8 PB gate junction potential V 1 0.6 9 IS gate junction saturation current (I ) A 1.0e-14 1.0e-14 * S 10 B doping tail parameter - 1 1.1 11 KF flicker noise coefficient - 0 12 AF flicker noise exponent - 1 13 FC coefficient for forward-bias - 0.5 depletion capacitance formula o 14 TNOM parameter measurement temperature C 27 50

3.4.7.MOSFETs

Generalform:

MXXXXXXX ND NG NS NB MNAME <L=VAL> <W=VAL> <AD=VAL> <AS=VAL> + <PD=VAL> <PS=VAL> <NRD=VAL> <NRS=VAL> <OFF> + <IC=VDS, VGS, VBS> <TEMP=T>

Examples:

M1 24 2 0 20 TYPE1 M31 2 17 6 10 MODM L=5U W=2U M1 2 9 3 0 MOD1 L=10U W=5U AD=100P AS=100P PD=40U PS=40U

ND, NG, NS, and NB are the drain, gate, source, and bulk (substrate) nodes, respectively. MNAME is the model name. L and W are the channel length and width, in meters. AD and AS are the areas of the drain and source diffusions, in 2 meters . Note that the suffix U specifies microns (1e-6 m) 2 and P sq-microns (1e-12 m ). If any of L, W, AD, or AS are not specified, default values are used. The use of defaults simplifies input file preparation, as well as the editing required if device geometries are to be changed. PD and PS are the perimeters of the drain and source junctions, in meters. NRD and NRS designate the equivalent number of squares of the drain and source diffusions; these values multiply the sheet resistance RSH specified on the .MODEL control line for an accurate representation of the parasitic series drain and source resistance of each transistor. PD and PS default to 0.0 while NRD and NRS to 1.0. OFF indi- cates an (optional) initial condition on the device for dc analysis. The (optional) initial condition specification using IC=VDS, VGS, VBS is intended for use with the UIC option on the .TRAN control line, when a transient analysis is desired starting from other than the quiescent operating point. See the .IC control line for a better and more con- venient way to specify transient initial conditions. The (optional) TEMP value is the temperature at which this dev- ice is to operate, and overrides the temperature specifica- tion on the .OPTION control line. The temperature specifi- cation is ONLY valid for level 1, 2, 3, and 6 MOSFETs, not for level 4 or 5 (BSIM) devices.

3.4.8.MOSFETModels(NMOS/PMOS)

SPICE provides four MOSFET device models, which differ in the formulation of the I-V characteristic. The variable LEVEL specifies the model to be used:

LEVEL=1 -> Shichman-Hodges LEVEL=2 -> MOS2 (as described in [1]) LEVEL=3 -> MOS3, a semi-empirical model(see [1]) LEVEL=4 -> BSIM (as described in [3]) LEVEL=5 -> new BSIM (BSIM2; as described in [5]) LEVEL=6 -> MOS6 (as described in [2])

The dc characteristics of the level 1 through level 3 MOS- FETs are defined by the device parameters VTO, KP, LAMBDA, PHI and GAMMA. These parameters are computed by SPICE if process parameters (NSUB, TOX, ...) are given, but user- specified values always override. VTO is positive (nega- tive) for enhancement mode and negative (positive) for depletion mode N-channel (P-channel) devices. Charge storage is modeled by three constant capacitors, CGSO, CGDO, and CGBO which represent overlap capacitances, by the non- linear thin-oxide capacitance which is distributed among the gate, source, drain, and bulk regions, and by the nonlinear depletion-layer capacitances for both substrate junctions divided into bottom and periphery, which vary as the MJ and MJSW power of junction voltage respectively, and are deter- mined by the parameters CBD, CBS, CJ, CJSW, MJ, MJSW and PB. Charge storage effects are modeled by the piecewise linear voltages-dependent capacitance model proposed by Meyer. The thin-oxide charge-storage effects are treated slightly dif- ferent for the LEVEL=1 model. These voltage-dependent capa- citances are included only if TOX is specified in the input description and they are represented using Meyer's formula- tion.

There is some overlap among the parameters describing the junctions, e.g. the reverse current can be input either 2 as IS (in A) or as JS (in A/m ). Whereas the first is an absolute value the second is multiplied by AD and AS to give the reverse current of the drain and source junctions respectively. This methodology has been chosen since there is no sense in relating always junction characteristics with AD and AS entered on the device line; the areas can be defaulted. The same idea applies also to the zero-bias junction capacitances CBD and CBS (in F) on one hand, and CJ 2 (in F/m ) on the other. The parasitic drain and source series resistance can be expressed as either RD and RS (in ohms) or RSH (in ohms/sq.), the latter being multiplied by the number of squares NRD and NRS input on the device line.

A discontinuity in the MOS level 3 model with respect to the KAPPA parameter has been detected (see [10]). The supplied fix has been implemented in Spice3f2 and later. Since this fix may affect parameter fitting, the option "BADMOS3" may be set to use the old implementation (see the section on simulation variables and the ".OPTIONS" line). SPICE level 1, 2, 3 and 6 parameters:

name parameter units default example

1 LEVEL model index - 1 2 VTO zero-bias threshold voltage (V ) V 0.0 1.0 TO 2 3 KP transconductance parameter A/V 2.0e-5 3.1e-5 1/2 4 GAMMA bulk threshold parameter (\) V 0.0 0.37 5 PHI surface potential (U) V 0.6 0.65 6 LAMBDA channel-length modulation (MOS1 and MOS2 only) (L) 1/V 0.0 0.02 7 RD drain ohmic resistance Z 0.0 1.0 8 RS source ohmic resistance Z 0.0 1.0 9 CBD zero-bias B-D junction capacitance F 0.0 20fF 10 CBS zero-bias B-S junction capacitance F 0.0 20fF 11 IS bulk junction saturation current (I ) A 1.0e-14 1.0e-15 S 12 PB bulk junction potential V 0.8 0.87 13 CGSO gate-source overlap capacitance per meter channel width F/m 0.0 4.0e-11 14 CGDO gate-drain overlap capacitance per meter channel width F/m 0.0 4.0e-11 15 CGBO gate-bulk overlap capacitance per meter channel length F/m 0.0 2.0e-10 16 RSH drain and source diffusion sheet resistance Z/[] 0.0 10.0 17 CJ zero-bias bulk junction bottom cap. 2 per sq-meter of junction area F/m 0.0 2.0e-4 18 MJ bulk junction bottom grading coeff. - 0.5 0.5 19 CJSW zero-bias bulk junction sidewall cap. per meter of junction perimeter F/m 0.0 1.0e-9 20 MJSW bulk junction sidewall grading coeff. - 0.50(level1) 0.33(level2, 3) 21 JS bulk junction saturation current 2 per sq-meter of junction area A/m 1.0e-8 22 TOX oxide thickness meter 1.0e-7 1.0e-7 3 23 NSUB substrate doping 1/cm 0.0 4.0e15 2 24 NSS surface state density 1/cm 0.0 1.0e10 2 25 NFS fast surface state density 1/cm 0.0 1.0e10

continued

name parameter units default example

26 TPG type of gate material: - 1.0 +1 opp. to substrate -1 same as substrate 0 Al gate 27 XJ metallurgical junction depth meter 0.0 1M 28 LD lateral diffusion meter 0.0 0.8M 2 29 UO surface mobility cm /Vs 600 700 30 UCRIT critical field for mobility degradation (MOS2 only) V/cm 1.0e4 1.0e4 31 UEXP critical field exponent in mobility degradation (MOS2 only) - 0.0 0.1 32 UTRA transverse field coeff. (mobility) (deleted for MOS2) - 0.0 0.3 33 VMAX maximum drift velocity of carriers m/s 0.0 5.0e4 34 NEFF total channel-charge (fixed and mobile) coefficient (MOS2 only) - 1.0 5.0 35 KF flicker noise coefficient - 0.0 1.0e-26 36 AF flicker noise exponent - 1.0 1.2 37 FC coefficient for forward-bias depletion capacitance formula - 0.5 38 DELTA width effect on threshold voltage (MOS2 and MOS3) - 0.0 1.0 39 THETA mobility modulation (MOS3 only) 1/V 0.0 0.1 40 ETA static feedback (MOS3 only) - 0.0 1.0 41 KAPPA saturation field factor (MOS3 only) - 0.2 0.5 o 42 TNOM parameter measurement temperature C 27 50

The level 4 and level 5 (BSIM1 and BSIM2) parameters are all values obtained from process characterization, and can be generated automatically. J. Pierret [4] describes a means of generating a 'process' file, and the program Proc2Mod provided with SPICE3 converts this file into a se- quence of BSIM1 ".MODEL" lines suitable for inclusion in a SPICE input file. Parameters marked below with an * in the l/w column also have corresponding parameters with a length and width dependency. For example, VFB is the basic parame- ter with units of Volts, and LVFB and WVFB also exist and have units of Volt-Mmeter The formula

P P L W P = P + ---------- + ---------- 0 L W effective effective

is used to evaluate the parameter for the actual device specified with

L = L - DL effective input and

W = W - DW effective input

Note that unlike the other models in SPICE, the BSIM model is designed for use with a process characterization system that provides all the parameters, thus there are no defaults for the parameters, and leaving one out is con- sidered an error. For an example set of parameters and the format of a process file, see the SPICE2 implementation notes[3].

For more information on BSIM2, see reference [5].

SPICE BSIM (level 4) parameters.

name parameter units l/w

VFB flat-band voltage V * PHI surface inversion potential V * 1/2 K1 body effect coefficient V * K2 drain/source depletion charge-sharing coefficient - * ETA zero-bias drain-induced barrier-lowering coefficient - * 2 MUZ zero-bias mobility cm /V-s DL shortening of channel Mm DW narrowing of channel Mm -1 U0 zero-bias transverse-field mobility degradation coefficient V * U1 zero-bias velocity saturation coefficient Mm/V * 2 2 X2MZ sens. of mobility to substrate bias at v =0 cm /V -s * ds -1 X2E sens. of drain-induced barrier lowering effect to substrate bias V * -1 X3E sens. of drain-induced barrier lowering effect to drain bias at V =V V * ds dd -2 X2U0 sens. of transverse field mobility degradation effect to substrate bias V * -2 X2U1 sens. of velocity saturation effect to substrate bias MmV * 2 2 MUS mobility at zero substrate bias and at V =V cm /V -s ds dd 2 2 X2MS sens. of mobility to substrate bias at V =V cm /V -s * ds dd 2 2 X3MS sens. of mobility to drain bias at V =V cm /V -s * ds dd -2 X3U1 sens. of velocity saturation effect on drain bias at V =V MmV * ds dd TOX gate oxide thickness Mm o TEMP temperature at which parameters were measured C VDD measurement bias range V CGDO gate-drain overlap capacitance per meter channel width F/m CGSO gate-source overlap capacitance per meter channel width F/m CGBO gate-bulk overlap capacitance per meter channel length F/m XPART gate-oxide capacitance-charge model flag - N0 zero-bias subthreshold slope coefficient - * NB sens. of subthreshold slope to substrate bias - * ND sens. of subthreshold slope to drain bias - * RSH drain and source diffusion sheet resistance Z/[] 2 JS source drain junction current density A/m PB built in potential of source drain junction V MJ Grading coefficient of source drain junction - PBSW built in potential of source, drain junction sidewall V MJSW grading coefficient of source drain junction sidewall - 2 CJ Source drain junction capacitance per unit area F/m CJSW source drain junction sidewall capacitance per unit length F/m WDF source drain junction default width m DELL Source drain junction length reduction m

XPART = 0 selects a 40/60 drain/source charge partition in saturation, while XPART=1 selects a 0/100 drain/source charge partition.

ND, NG, and NS are the drain, gate, and source nodes, respectively. MNAME is the model name, AREA is the area factor, and OFF indicates an (optional) initial condition on the device for dc analysis. If the area factor is omitted, a value of 1.0 is assumed. The (optional) initial condition specification, using IC=VDS, VGS is intended for use with the UIC option on the .TRAN control line, when a transient analysis is desired starting from other than the quiescent operating point. See the .IC control line for a better way to set initial conditions.

3.4.9.MESFETs

Generalform:

ZXXXXXXX ND NG NS MNAME <AREA> <OFF> <IC=VDS, VGS>

Examples:

Z1 7 2 3 ZM1 OFF

3.4.10.MESFETModels(NMF/PMF)

The MESFET model is derived from the GaAs FET model of Statz et al. as described in [11]. The dc characteristics are defined by the parameters VTO, B, and BETA, which deter- mine the variation of drain current with gate voltage, AL- PHA, which determines saturation voltage, and LAMBDA, which determines the output conductance. The formula are given by:

3 2 B (V -V ) | | V | | 3 gs T ds _ I = --------------- |1 - |1-A---| |(1 + L V ) for 0 < V < d ds ds 1 + b(V - V ) | | 3 | | A gs T 2 B (V -V ) 3 gs T _ I = ---------------(1 + L V ) for V > d ds ds 1 + b(V - V ) A gs T

Two ohmic resistances, RD and RS, are included. Charge storage is modeled by total gate charge as a function of gate-drain and gate-source voltages and is defined by the parameters CGS, CGD, and PB.

name parameter units default example area

1 VTO pinch-off voltage V -2.0 -2.0 2 2 BETA transconductance parameter A/V 1.0e-4 1.0e-3 * 3 B doping tail extending parameter 1/V 0.3 0.3 * 4 ALPHA saturation voltage parameter 1/V 2 2 * 5 LAMBDA channel-length modulation parameter 1/V 0 1.0e-4 6 RD drain ohmic resistance Z 0 100 * 7 RS source ohmic resistance Z 0 100 * 8 CGS zero-bias G-S junction capacitance F 0 5pF * 9 CGD zero-bias G-D junction capacitance F 0 1pF * 10 PB gate junction potential V 1 0.6 11 KF flicker noise coefficient - 0 12 AF flicker noise exponent - 1 13 FC coefficient for forward-bias - 0.5 depletion capacitance formula

4.ANALYSESANDOUTPUTCONTROL

The following command lines are for specifying analyses or plots within the circuit description file. Parallel com- mands exist in the interactive command interpreter (detailed in the following section). Specifying analyses and plots (or tables) in the input file is useful for batch runs. Batch mode is entered when either the -b option is given or when the default input source is redirected from a file. In batch mode, the analyses specified by the control lines in the input file (e.g. ".ac", ".tran", etc.) are immediately executed (unless ".control" lines exists; see the section on the interactive command interpretor). If the -rrawfileoption is given then all data generated is written to a Spice3 rawfile. The rawfile may be read by either the interactive mode of Spice3 or by nutmeg; see the previous section for details. In this case, the .SAVE line (see below) may be used to record the value of internal device variables (see Appendix B).

If a rawfile is not specified, then output plots (in "line-printer" form) and tables can be printed according to the .PRINT, .PLOT, and .FOUR control lines, described next. .PLOT, .PRINT, and .FOUR lines are meant for compatibility with Spice2.

SIMULATOR VARIABLES | INITIAL CONDITIONS | ANALYSES | BATCH OUTPUT |

4.1.SIMULATORVARIABLES(.OPTIONS)

Various parameters of the simulations available in Spice3 can be altered to control the accuracy, speed, or default values for some devices. These parameters may be changed via the "set" command (described later in the sec- tion on the interactive front-end) or via the ".OPTIONS" line:

Generalform:

.OPTIONS OPT1 OPT2 ... (or OPT=OPTVAL ...)

Examples:

.OPTIONS RELTOL=.005 TRTOL=8

The options line allows the user to reset program con- trol and user options for specific simulation purposes. Additional options for Nutmeg may be specified as well and take effect when Nutmeg reads the input file. Options specified to Nutmeg via the 'set' command are also passed on to SPICE3 as if specified on a .OPTIONS line. See the fol- lowing section on the interactive command interpreter for the parameters which may be set with a .OPTIONS line and the format of the 'set' command. Any combination of the follow- ing options may be included, in any order. 'x' (below) represents some positive number.

option effect

ABSTOL=x resets the absolute current error tolerance of the program. The default value is 1 picoamp. BADMOS3 Use the older version of the MOS3 model with the "kappa" discontinuity. CHGTOL=x resets the charge tolerance of the program. The default value is 1.0e-14. DEFAD=x resets the value for MOS drain diffusion area; the default is 0.0. DEFAS=x resets the value for MOS source diffusion area; the default is 0.0. DEFL=x resets the value for MOS channel length; the default is 100.0 micrometer. DEFW=x resets the value for MOS channel width; the default is 100.0 micrometer. GMIN=x resets the value of GMIN, the minimum conductance allowed by the program. The default value is 1.0e-12. ITL1=x resets the dc iteration limit. The default is 100. ITL2=x resets the dc transfer curve iteration limit. The default is 50. ITL3=x resets the lower transient analysis iteration limit. the default value is 4. (Note: not implemented in Spice3). ITL4=x resets the transient analysis timepoint iteration limit. the default is 10. ITL5=x resets the transient analysis total iteration limit. the default is 5000. Set ITL5=0 to omit this test. (Note: not implemented in Spice3). KEEPOPINFO Retain the operating point information when either an AC, Distortion, or Pole-Zero analysis is run. This is particularly useful if the circuit is large and you do not want to run a (redundant) ".OP" analysis. METHOD=name sets the numerical integration method used by SPICE. Possible names are "Gear" or "trapezoidal" (or just "trap"). The default is trapezoidal. PIVREL=x resets the relative ratio between the largest column entry and an acceptable pivot value. The default value is 1.0e-3. In the numerical pivoting algorithm the allowed minimum pivot value is determined by EPSREL=AMAX1(PIVREL*MAXVAL, PIVTOL) where MAXVAL is the maximum element in the column where a pivot is sought (partial pivoting). PIVTOL=x resets the absolute minimum value for a matrix entry to be accepted as a pivot. The default value is 1.0e-13. RELTOL=x resets the relative error tolerance of the program. The default value is 0.001 (0.1%). TEMP=x Resets the operating temperature of the circuit. The default value is 27 deg C (300 deg K). TEMP can be overridden by a temperature specification on any temperature dependent instance. TNOM=x resets the nominal temperature at which device parameters are measured. The default value is 27 deg C (300 deg K). TNOM can be overridden by a specification on any temperature dependent device model. TRTOL=x resets the transient error tolerance. The default value is 7.0. This parameter is an estimate of the factor by which SPICE overestimates the actual truncation error. TRYTOCOMPACT Applicable only to the LTRA model. When specified, the simulator tries to condense LTRA transmission lines' past history of input voltages and currents. VNTOL=x resets the absolute voltage error tolerance of the program. The default value is 1 microvolt.

In addition, the following options have the listed effect when operating in spice2 emulation mode:

option effect

option effect ACCT causes accounting and run time statistics to be printed LIST causes the summary listing of the input data to be printed NOMOD suppresses the printout of the model parameters NOPAGE suppresses page ejects NODE causes the printing of the node table. OPTS causes the option values to be printed.

4.2.INITIALCONDITIONS

.NODESET | .IC |

4.2.1. .NODESET:SpecifyInitialNodeVoltageGuesses

Generalform:

.NODESET V(NODNUM)=VAL V(NODNUM)=VAL ...

Examples:

.NODESET V(12)=4.5 V(4)=2.23

The Nodeset line helps the program find the dc or ini- tial transient solution by making a preliminary pass with the specified nodes held to the given voltages. The res- triction is then released and the iteration continues to the true solution. The .NODESET line may be necessary for con- vergence on bistable or a-stable circuits. In general, this line should not be necessary.

4.2.2. .IC:SetInitialConditions

Generalform:

.IC V(NODNUM)=VAL V(NODNUM)=VAL ...

Examples:

.IC V(11)=5 V(4)=-5 V(2)=2.2

The IC line is for setting transient initial condi- tions. It has two different interpretations, depending on whether the UIC parameter is specified on the .TRAN control line. Also, one should not confuse this line with the .NODESET line. The .NODESET line is only to help dc conver- gence, and does not affect final bias solution (except for multi-stable circuits). The two interpretations of this line are as follows:

1. When the UIC parameter is specified on the .TRAN line, then the node voltages specified on the .IC control line are used to compute the capacitor, diode, BJT, JFET, and MOSFET initial conditions. This is equivalent to specifying the IC=... parameter on each device line, but is much more con- venient. The IC=... parameter can still be specified and takes precedence over the .IC values. Since no dc bias (initial transient) solution is computed before the tran- sient analysis, one should take care to specify all dc source voltages on the .IC control line if they are to be used to compute device initial conditions.

2. When the UIC parameter is not specified on the .TRAN control line, the dc bias (initial transient) solution is computed before the transient analysis. In this case, the node voltages specified on the .IC control line is forced to the desired initial values during the bias solution. During transient analysis, the constraint on these node voltages is removed. This is the preferred method since it allows SPICE to compute a consistent dc solution.

4.3.ANALYSES

.AC | .NOISE | .SENS | |

.DC | .OP | .TF | |

.DISTO | .PZ | .TRAN |

4.3.1. .AC:Small-SignalACAnalysis

Generalform:

.AC DEC ND FSTART FSTOP .AC OCT NO FSTART FSTOP .AC LIN NP FSTART FSTOP

Examples:

.AC DEC 10 1 10K .AC DEC 10 1K 100MEG .AC LIN 100 1 100HZ

DEC stands for decade variation, and ND is the number of points per decade. OCT stands for octave variation, and NO is the number of points per octave. LIN stands for linear variation, and NP is the number of points. FSTART is the starting frequency, and FSTOP is the final frequency. If this line is included in the input file, SPICE performs an AC analysis of the circuit over the specified frequency range. Note that in order for this analysis to be meaning- ful, at least one independent source must have been speci- fied with an ac value.

4.3.2. .DC:DCTransferFunction

Generalform:

.DC SRCNAM VSTART VSTOP VINCR [SRC2 START2 STOP2 INCR2]

Examples:

.DC VIN 0.25 5.0 0.25 .DC VDS 0 10 .5 VGS 0 5 1 .DC VCE 0 10 .25 IB 0 10U 1U

The DC line defines the dc transfer curve source and sweep limits (again with capacitors open and inductors shorted). SRCNAM is the name of an independent voltage or current source. VSTART, VSTOP, and VINCR are the starting, final, and incrementing values respectively. The first example causes the value of the voltage source VIN to be swept from 0.25 Volts to 5.0 Volts in increments of 0.25 Volts. A second source (SRC2) may optionally be specified with associated sweep parameters. In this case, the first source is swept over its range for each value of the second source. This option can be useful for obtaining semiconduc- tor device output characteristics. See the second example circuit description in Appendix A.

4.3.3. .DISTO:DistortionAnalysis

Generalform:

.DISTO DEC ND FSTART FSTOP <F2OVERF1> .DISTO OCT NO FSTART FSTOP <F2OVERF1> .DISTO LIN NP FSTART FSTOP <F2OVERF1>

Examples:

.DISTO DEC 10 1kHz 100Mhz .DISTO DEC 10 1kHz 100Mhz 0.9

The Disto line does a small-signal distortion analysis of the circuit. A multi-dimensional Volterra series analysis is done using multi-dimensional Taylor series to represent the nonlinearities at the operating point. Terms of up to third order are used in the series expansions.

If the optional parameter F2OVERF1 is not specified, .DISTO does a harmonic analysis - i.e., it analyses distor- tion in the circuit using only a single input frequency F1, which is swept as specified by arguments of the .DISTO com- mand exactly as in the .AC command. Inputs at this fre- quency may be present at more than one input source, and their magnitudes and phases are specified by the arguments of the DISTOF1 keyword in the input file lines for the input sources (see the description for independent sources). (The arguments of the DISTOF2 keyword are not relevant in this case). The analysis produces information about the A.C. values of all node voltages and branch currents at the har- monic frequencies 2F1 and 3F1, vs. the input frequency F1 as it is swept. (A value of 1 (as a complex distortion output) signifies cos(2J(2F1)t) at 2F1 and cos(2J(3F1)t) at 3F1, using the convention that 1 at the input fundamental fre- quency is equivalent to cos(2JF1t).) The distortion com- ponent desired (2F1 or 3F1) can be selected using commands in nutmeg, and then printed or plotted. (Normally, one is interested primarily in the magnitude of the harmonic com- ponents, so the magnitude of the AC distortion value is looked at). It should be noted that these are the A.C. values of the actual harmonic components, and are not equal to HD2 and HD3. To obtain HD2 and HD3, one must divide by the corresponding A.C. values at F1, obtained from an .AC line. This division can be done using nutmeg commands.

If the optional F2OVERF1 parameter is specified, it should be a real number between (and not equal to) 0.0 and 1.0; in this case, .DISTO does a spectral analysis. It con- siders the circuit with sinusoidal inputs at two different frequencies F1 and F2. F1 is swept according to the .DISTO control line options exactly as in the .AC control line. F2 is kept fixed at a single frequency as F1 sweeps - the value at which it is kept fixed is equal to F2OVERF1 times FSTART. Each independent source in the circuit may potentially have two (superimposed) sinusoidal inputs for distortion, at the frequencies F1 and F2. The magnitude and phase of the F1 component are specified by the arguments of the DISTOF1 key- word in the source's input line (see the description of independent sources); the magnitude and phase of the F2 com- ponent are specified by the arguments of the DISTOF2 key- word. The analysis produces plots of all node voltages/branch currents at the intermodulation product fre- quencies F1 + F2, F1 - F2, and (2 F1) - F2, vs the swept frequency F1. The IM product of interest may be selected using the setplot command, and displayed with the print and plot commands. It is to be noted as in the harmonic analysis case, the results are the actual AC voltages and currents at the intermodulation frequencies, and need to be normalized with respect to .AC values to obtain the IM parameters.

If the DISTOF1 or DISTOF2 keywords are missing from the description of an independent source, then that source is assumed to have no input at the corresponding frequency. The default values of the magnitude and phase are 1.0 and 0.0 respectively. The phase should be specified in degrees.

It should be carefully noted that the number F2OVERF1 should ideally be an irrational number, and that since this is not possible in practice, efforts should be made to keep the denominator in its fractional representation as large as possible, certainly above 3, for accurate results (i.e., if F2OVERF1 is represented as a fraction A/B, where A and B are integers with no common factors, B should be as large as possible; note that A < B because F2OVERF1 is constrained to be < 1). To illustrate why, consider the cases where F2OVERF1 is 49/100 and 1/2. In a spectral analysis, the outputs produced are at F1 + F2, F1 - F2 and 2 F1 - F2. In the latter case, F1 - F2 = F2, so the result at the F1-F2 component is erroneous because there is the strong fundamen- tal F2 component at the same frequency. Also, F1 + F2 = 2 F1 - F2 in the latter case, and each result is erroneous individually. This problem is not there in the case where F2OVERF1 = 49/100, because F1-F2 = 51/100 F1 < > 49/100 F1 = F2. In this case, there are two very closely spaced fre- quency components at F2 and F1 - F2. One of the advantages of the Volterra series technique is that it computes distor- tions at mix frequencies expressed symbolically (i.e. n F1 + m F2), therefore one is able to obtain the strengths of dis- tortion components accurately even if the separation between them is very small, as opposed to transient analysis for example. The disadvantage is of course that if two of the mix frequencies coincide, the results are not merged together and presented (though this could presumably be done as a postprocessing step). Currently, the interested user should keep track of the mix frequencies himself or herself and add the distortions at coinciding mix frequencies together should it be necessary.

4.3.4. .NOISE:NoiseAnalysis

Generalform:

.NOISE V(OUTPUT <,REF>) SRC ( DEC | LIN | OCT ) PTS FSTART FSTOP + <PTS_PER_SUMMARY>

Examples:

.NOISE V(5) VIN DEC 10 1kHZ 100Mhz .NOISE V(5,3) V1 OCT 8 1.0 1.0e6 1

The Noise line does a noise analysis of the circuit. OUTPUT is the node at which the total output noise is desired; if REF is specified, then the noise voltage V(OUTPUT) - V(REF) is calculated. By default, REF is assumed to be ground. SRC is the name of an independent source to which input noise is referred. PTS, FSTART and FSTOP are .AC type parameters that specify the frequency range over which plots are desired. PTS_PER_SUMMARY is an optional integer; if specified, the noise contributions of each noise generator is produced every PTS_PER_SUMMARY fre- quency points.

The .NOISE control line produces two plots - one for the Noise Spectral Density curves and one for the total Integrated Noise over the specified frequency range. All 2 noise voltages/currents are in squared units (V /Hz and 2 2 2 A /Hz for spectral density, V and A for integrated noise).

4.3.5. .OP:OperatingPointAnalysis

Generalform:

.OP

The inclusion of this line in an input file directs SPICE to determine the dc operating point of the circuit with inductors shorted and capacitors opened. Note: a DC analysis is automatically performed prior to a transient analysis to determine the transient initial conditions, and prior to an AC small-signal, Noise, and Pole-Zero analysis to determine the linearized, small-signal models for non- linear devices (see the KEEPOPINFO variable above).

4.3.6. .PZ:Pole-ZeroAnalysis

Generalform:

.PZ NODE1 NODE2 NODE3 NODE4 CUR POL .PZ NODE1 NODE2 NODE3 NODE4 CUR ZER .PZ NODE1 NODE2 NODE3 NODE4 CUR PZ .PZ NODE1 NODE2 NODE3 NODE4 VOL POL .PZ NODE1 NODE2 NODE3 NODE4 VOL ZER .PZ NODE1 NODE2 NODE3 NODE4 VOL PZ

Examples:

.PZ 1 0 3 0 CUR POL .PZ 2 3 5 0 VOL ZER .PZ 4 1 4 1 CUR PZ

CUR stands for a transfer function of the type (output voltage)/(input current) while VOL stands for a transfer function of the type (output voltage)/(input voltage). POL stands for pole analysis only, ZER for zero analysis only and PZ for both. This feature is provided mainly because if there is a nonconvergence in finding poles or zeros, then, at least the other can be found. Finally, NODE1 and NODE2 are the two input nodes and NODE3 and NODE4 are the two out- put nodes. Thus, there is complete freedom regarding the output and input ports and the type of transfer function.

In interactive mode, the command syntax is the same except that the first field is PZ instead of .PZ. To print the results, one should use the command 'print all'.

4.3.7. .SENS:DCorSmall-SignalACSensitivityAnalysis

Generalform:

.SENS OUTVAR .SENS OUTVAR AC DEC ND FSTART FSTOP .SENS OUTVAR AC OCT NO FSTART FSTOP .SENS OUTVAR AC LIN NP FSTART FSTOP

Examples:

.SENS V(1,OUT) .SENS V(OUT) AC DEC 10 100 100k .SENS I(VTEST)

The sensitivity of OUTVAR to all non-zero device param- eters is calculated when the SENS analysis is specified. OUTVAR is a circuit variable (node voltage or voltage-source branch current). The first form calculates sensitivity of the DC operating-point value of OUTVAR. The second form calculates sensitivity of the AC values of OUTVAR. The parameters listed for AC sensitivity are the same as in an AC analysis (see ".AC" above). The output values are in dimensions of change in output per unit change of input (as opposed to percent change in output or per percent change of input).

4.3.8. .TF:TransferFunctionAnalysis

Generalform:

.TF OUTVAR INSRC

Examples:

.TF V(5, 3) VIN .TF I(VLOAD) VIN

The TF line defines the small-signal output and input for the dc small-signal analysis. OUTVAR is the small- signal output variable and INSRC is the small-signal input source. If this line is included, SPICE computes the dc small-signal value of the transfer function (output/input), input resistance, and output resistance. For the first example, SPICE would compute the ratio of V(5, 3) to VIN, the small-signal input resistance at VIN, and the small- signal output resistance measured across nodes 5 and 3.

4.3.9. .TRAN:TransientAnalysis

Generalform:

.TRAN TSTEP TSTOP <TSTART <TMAX>>

Examples:

.TRAN 1NS 100NS .TRAN 1NS 1000NS 500NS .TRAN 10NS 1US

TSTEP is the printing or plotting increment for line- printer output. For use with the post-processor, TSTEP is the suggested computing increment. TSTOP is the final time, and TSTART is the initial time. If TSTART is omitted, it is assumed to be zero. The transient analysis always begins at time zero. In the interval <zero, TSTART>, the circuit is analyzed (to reach a steady state), but no outputs are stored. In the interval <TSTART, TSTOP>, the circuit is analyzed and outputs are stored. TMAX is the maximum step- size that SPICE uses; for default, the program chooses either TSTEP or (TSTOP-TSTART)/50.0, whichever is smaller. TMAX is useful when one wishes to guarantee a computing interval which is smaller than the printer increment, TSTEP.

UIC (use initial conditions) is an optional keyword which indicates that the user does not want SPICE to solve for the quiescent operating point before beginning the tran- sient analysis. If this keyword is specified, SPICE uses the values specified using IC=... on the various elements as the initial transient condition and proceeds with the analysis. If the .IC control line has been specified, then the node voltages on the .IC line are used to compute the initial conditions for the devices. Look at the description on the .IC control line for its interpretation when UIC is not specified.

4.4.BATCHOUTPUT

.SAVE Lines | .PRINT Lines | .PLOT Lines | .FOUR |

4.4.1. .SAVELines

Generalform:

.SAVEvectorvectorvector...

Examples:

.SAVE i(vin) input output .SAVE @m1[id]

The vectors listed on the .SAVE line are recorded in the rawfile for use later with spice3 or nutmeg (nutmeg is just the data-analysis half of spice3, without the ability to simulate). The standard vector names are accepted. If no .SAVE line is given, then the default set of vectors are saved (node voltages and voltage source branch currents). If .SAVE lines are given, only those vectors specified are saved. For more discussion on internal device data, see Appendix B. See also the section on the interactive command interpretor for information on how to use the rawfile.

4.4.2. .Lines

Generalform:

.PRINT PRTYPE OV1 <OV2 ... OV8>

Examples:

.PRINT TRAN V(4) I(VIN) .PRINT DC V(2) I(VSRC) V(23, 17) .PRINT AC VM(4, 2) VR(7) VP(8, 3)

The Print line defines the contents of a tabular list- ing of one to eight output variables. PRTYPE is the type of the analysis (DC, AC, TRAN, NOISE, or DISTO) for which the specified outputs are desired. The form for voltage or current output variables is the same as given in the previ- ous section for the print command; Spice2 restricts the out- put variable to the following forms (though this restriction is not enforced by Spice3):

V(N1<,N2>) specifies the voltage difference between nodes N1 and N2. If N2 (and the preceding comma) is omit- ted, ground (0) is assumed. See the print command in the previous section for more details. For compatibility with spice2, the following five additional values can be accessed for the ac analysis by replacing the "V" in V(N1,N2) with:

VR - real part VI - imaginary part VM - magnitude VP - phase VDB - 20 log10(magnitude)

I(VXXXXXXX) specifies the current flowing in the independent voltage source named VXXXXXXX. Positive current flows from the positive node, through the source, to the negative node. For the ac analysis, the corresponding replacements for the letter I may be made in the same way as described for voltage out- puts.

Output variables for the noise and distortion analyses have a different general form from that of the other ana- lyses.

There is no limit on the number of .PRINT lines for each type of analysis.

4.4.3. .PLOTLines

Generalform:

.PLOT PLTYPE OV1 <(PLO1, PHI1)> <OV2 <(PLO2, PHI2)> ... OV8>

Examples:

.PLOT DC V(4) V(5) V(1) .PLOT TRAN V(17, 5) (2, 5) I(VIN) V(17) (1, 9) .PLOT AC VM(5) VM(31, 24) VDB(5) VP(5) .PLOT DISTO HD2 HD3(R) SIM2 .PLOT TRAN V(5, 3) V(4) (0, 5) V(7) (0, 10)

The Plot line defines the contents of one plot of from one to eight output variables. PLTYPE is the type of analysis (DC, AC, TRAN, NOISE, or DISTO) for which the specified outputs are desired. The syntax for the OVI is identical to that for the .PRINT line and for the plot command in the interactive mode.

The overlap of two or more traces on any plot is indi- cated by the letter X.

When more than one output variable appears on the same plot, the first variable specified is printed as well as plotted. If a printout of all variables is desired, then a companion .PRINT line should be included.

There is no limit on the number of .PLOT lines speci- fied for each type of analysis.

4.4.4. .FOUR:FourierAnalysisofTransientAnalysisOut-put

Generalform:

.FOUR FREQ OV1 <OV2 OV3 ...>

Examples:

.FOUR 100K V(5)

The Four (or Fourier) line controls whether SPICE performs a Fourier analysis as a part of the transient analysis. FREQ is the fundamental frequency, and OV1, desired. The Fourier analysis is performed over the in- terval <TSTOP-period, TSTOP>, where TSTOP is the final time specified for the transient analysis, and period is one period of the fundamental frequency. The dc com- ponent and the first nine harmonics are determined. For maximum accuracy, TMAX (see the .TRAN line) should be set to period/100.0 (or less for very high-Q circuits).

5.INTERACTIVEINTERPRETER

Spice3 consists of a simulator and a front-end for data analysis and plotting. The front-end may be run as a separate "stand-alone" program under the name Nutmeg.

Nutmegwill read in the "raw" data output file created by spice -r or with the write command in an interactive Spice3 session. Nutmeg or interactive Spice3 can plot data from a simulation on a graphics terminal or a workstation display. Most of the commands available in the interactive Spice3 front end are available in nutmeg; where this is not the case, Spice-only commands have been marked with an asterisk ("*"). Note that the raw output file is different from the data that Spice2 writes to the standard output, which may also be produced by spice3 with the "-b" command line option.

Spice and Nutmeg use the X Window System for plotting if they find the environment variable DISPLAY. Otherwise, a graphics-terminal independent interface (MFB) is used. If you are using X on a workstation, the DISPLAY variable should already be set; if you want to display graphics on a system different from the one you are running Spice3 or Nut- meg on, DISPLAY should be of the form "machine:0.0". See the appropriate documentation on the X Window Sytem for more details.

CommandSynopsis

spice [ -n ] [ -t term ] [ -r rawfile] [ -b ] [ -i ] [ input file ... ]

nutmeg [ - ] [ -n ] [ -t term ] [ datafile ... ]

Options are:

- Don't try to load the default data file ("rawspice.raw") if no other files are given. Nutmeg only.

-n (or -N) Don't try to source the file ".spiceinit" upon startup. Normally spice and nutmeg try to find the file in the current directory, and if it is not found then in the user's home directory.

-t term (or -T term) The program is being run on a terminal withmfbname term.

-b (or -B) Run in batch mode. Spice3 reads the default input source (e.g. keyboard) or reads the given input file and performs the analyses specified; output is either Spice2-like line-printer plots ("ascii plots") or a spice rawfile. See the following section for details. Note that if the input source is not a terminal (e.g. using the IO redirection notation of "<") Spice3 de- faults to batch mode (-i overrides). This option is valid for Spice3 only.

-s (or -S) Run in server mode. This is like batch mode, except that a temporary rawfile is used and then written to the standard output, preceded by a line with a single "@", after the simulation is done. This mode is used by the spice daemon. This option is valid for Spice3 only.

-i (or -I) Run in interactive mode. This is useful if the stan- dard input is not a terminal but interactive mode is desired. Command completion is not available unless the standard input is a terminal, however. This option is valid for Spice3 only.

-rrawfile(or -Prawfile) Userawfileas the default file into which the results of the simulation are saved. This option is valid for Spice3 only.

Further arguments to spice are taken to be Spice3 input files, which are read and saved (if running in batch mode then they are run immediately). Spice3 accepts most Spice2 input file, and output ascii plots, fourier analyses, and node printouts as specified in .plot, .four, and .print cards. If an out parameter is given on a .width card, the effect is the same as set width = .... Since Spice3 ascii plots do not use multiple ranges, however, if vectors together on a .plot card have different ranges they are not provide as much information as they would in Spice2. The output of Spice3 is also much less verbose than Spice2, in that the only data printed is that requested by the above cards.

For nutmeg, further arguments are taken to be data files in binary or ascii format (see sconvert(1)) which are loaded into nutmeg. If the file is in binary format, it may be only partially completed (useful for examining Spice2 output before the simulation is finished). One file may contain any number of data sets from different analyses.

EXPRESSIONS FUNCTIONS AND CONSTANTS | COMMANDS | VARIABLES | BUGS |

COMMAND INTERPRETATION | CONTROL STRUCTURES | MISCELLANEOUS |

5.1.EXPRESSIONS,FUNCTIONS,ANDCONSTANTS

Spice and Nutmeg data is in the form of vectors: time, voltage, etc. Each vector has a type, and vectors can be operated on and combined algebraicly in ways consistent with their types. Vectors are normally created when a data file is read in (see theloadcommand below), and when the ini- tial datafile is loaded. They can also be created with theletcommand.

An expression is an algebraic formula involving vectors and scalars (a scalar is a vector of length 1) and the fol- lowing operations:

+ - * / ^ %

% is the modulo operator, and the comma operator has two meanings: if it is present in the argument list of a user- definable function, it serves to separate the arguments. Otherwise, the term x , y is synonymous with x + j(y).

Also available are the logical operations & (and), | (or), ! (not), and the relational operations <, >, >=, <=, =, and <> (not equal). If used in an algebraic expression they work like they would in C, producing values of 0 or 1. The relational operators have the following synonyms:

gt > lt < ge >= le <= ne <> eq = and & or | not !

These are useful when < and > might be confused with IO redirection (which is almost always).

The following functions are available:

mag(vector) The magnitude of vector ph(vector) The phase of vector j(vector)i(sqrt(-1)) times vector real(vector) The real component of vector imag(vector) The imaginary part of vector db(vector) 20 log10(mag(vector)) log(vector) The logarithm (base 10) of vector ln(vector) The natural logarithm (base e) of vector exp(vector) e to the vector power abs(vector) The absolute value of vector. sqrt(vector) The square root of vector. sin(vector) The sine of vector. cos(vector) The cosine of vector. tan(vector) The tangent of vector. atan(vector) The inverse tangent of vector. norm(vector) The vector normalized to 1 (i.e, the largest magnitude of any component is 1). rnd(vector) A vector with each component a random integer between 0 and the absolute value of the vectors's corresponding com- ponent. mean(vector) The result is a scalar (a length 1 vec- tor) that is the mean of the elements of vector. vector(number) The result is a vector of length number, with elements 0, 1, ... number - 1. If number is a vector then just the first element is taken, and if it isn't an in- teger then the floor of the magnitude is used. length(vector) The length of vector. interpolate(plot.vector) The result of interpolating the named vector onto the scale of the current plot. This function uses the variable polydegree to determine the degree of interpolation. deriv(vector) Calculates the derivative of the given vector. This uses numeric differentia- tion by interpolating a polynomial and may not produce satisfactory results (particularly with iterated differentia- tion). The implementation only cacu- lates the dirivative with respect to the real componant of that vector's scale.

A vector may be either the name of a vector already defined or a floating-point number (a scalar). A number may be written in any format acceptable to SPICE, such as 14.6Meg or -1.231e-4. Note that you can either use scien- tific notation or one of the abbreviations likeMEGorG, but not both. As with SPICE, a number may have trailing alphabetic characters after it.

The notation expr [num] denotes the num'th element of expr. For multi-dimensional vectors, a vector of one less dimension is returned. Also for multi-dimensional vectors, the notation expr[m][n] will return thenth element of the mth subvector. To get a subrange of a vector, use the form expr[lower, upper].

To reference vectors in a plot that is not thecurrentplot(see the setplot command, below), the notation plotname.vecname can be used.

Either a plotname or a vector name may be the wildcard all. If the plotname is all, matching vectors from all plots are specified, and if the vector name is all, all vec- tors in the specified plots are referenced. Note that you may not use binary operations on expressions involving wild- cards - it is not obvious what all + all should denote, for instance. Thus some (contrived) examples of expressions are:

cos(TIME) + db(v(3)) sin(cos(log([1 2 3 4 5 6 7 8 9 10]))) TIME * rnd(v(9)) - 15 * cos(vin#branch) ^ [7.9e5 8] not ((ac3.FREQ[32] & tran1.TIME[10]) gt 3)

Vector names in spice may have a name such as @name[param], where name is either the name of a device instance or model. This denotes the value of the param parameter of the device or model. See Appendix B for details of what parameters are available. The value is a vector of length 1. This function is also available with the show command, and is available with variables for con- venience for command scripts.

There are a number of pre-defined constants in nutmeg. They are:

pi J (3.14159...) e The base of natural logarithms (2.71828...) c The speed of light (299,792,500 m/sec) i The square root of -1 o kelvin Absolute 0 in Centigrade (-273.15 C) echarge The charge on an electron (1.6021918e-19 C) boltz Boltzman's constant (1.3806226e-23) planck Planck's constant (h = 6.626200e-34)

These are all in MKS units. If you have another vari- able with a name that conflicts with one of these then it takes precedence.

5.2.COMMANDINTERPRETATION

If a word is typed as a command, and there is no built-in command with that name, the directories in thesourcepathlist are searched in order for the file. If it is found, it is read in as a command file (as if it were sourced). Before it is read, however, the variablesargcandargvare set to the number of words following the filename on the command line, and a list of those words respectively. After the file is finished, these variables are unset. Note that if a command file calls another, it must save itsargvandargcsince they are altered. Also, command files may not be re-entrant since there are no local variables. (Of course, the procedures may explicitly mani- pulate a stack...) This way one can write scripts analogous to shell scripts for nutmeg and Spice3.

Note that for the script to work with Spice3, it must begin with a blank line (or whatever else, since it is thrown away) and then a line with .control on it. This is an unfortunate result of the source command being used for both circuit input and command file execution. Note also that this allows the user to merely type the name of a cir- cuit file as a command and it is automatically run. The commands are executed immediately, without running any ana- lyses that may be spicified in the circuit (to execute the analyses before the script executes, include a "run" command in the script).

There are various command scripts installed in /usr/local/lib/spice/scripts(or whatever the path is on your machine), and the defaultsourcepathincludes this directory, so you can use these command files (almost) like builtin commands.

5.3.COMMANDS

5.3.1.Ac*:PerformanAC,small-signalfrequencyresponseanalysis

GeneralForm

ac ( DEC | OCT | LIN )NFstartFstop

Do an ac analysis. See the previous sections of this manual for more details.

5.3.2.Alias:Createanaliasforacommand

GeneralForm

alias [word] [text ...]

Causes word to be aliased to text. History substi- tutions may be used, as in C-shell aliases.

5.3.3.Alter*:Changeadeviceormodelparameter

GeneralForm

alterdevicevaluealterdeviceparametervalue[parametervalue]

Alter changes the value for a device or a specified parameter of a device or model. The first form is used by simple devices which have one principal value (resis- tors, capacitors, etc.) where the second form is for more complex devices (bjt's, etc.). Model parameters can be changed with the second form if the name contains a "#".

For specifying vectors as values, start the vector with "[", followed by the values in the vector, and end with "]". Be sure to place a space between each of the values and before and after the "[" and "]".

5.3.4.Asciiplot:Plotvaluesusingold-stylecharacterplots

GeneralForm

asciiplotplotargs

Produce a line printer plot of the vectors. The plot is sent to the standard output, so you can put it into a file withasciiplotargs... >file. The set op- tions width, height, and nobreak determine the width and height of the plot, and whether there are page breaks, respectively. Note that you will have problems if you try to asciiplot something with an X-scale that isn't monotonic (i.e, something likesin(TIME) ), because as- ciiplot uses a simple-minded linear interpolation.

5.3.5.Aspice:Asynchronousspicerun

GeneralForm

aspice input-file [output-file]

Start a SPICE-3 run, and when it is finished load the resulting data. The raw data is kept in a temporary file. Ifoutput-fileis specified then the diagnostic output is directed into that file, otherwise it is thrown away.

5.3.6.Bug:abugreport

GeneralForm

bug

Send a bug report. Please include a short summary of the problem, the version number and name of the operating system that you are running, the version of Spice that you are running, and the relevant spice input file. (If you have defined BUGADDR, the mail is delivered to there.)

5.3.7.Cd:Changedirectory

GeneralForm

cd [directory]

Change the current working directory to directory, or to the user's home directory if none is given.

5.3.8.Destroy:Deleteadataset

GeneralForm

destroy [plotnames| all]

Release the memory holding the data for the speci- fied runs.

5.3.9.Dc*:PerformaDC-sweepanalysis

GeneralForm

dcSource-NameVstartVstopVincr[Source2Vstart2Vstop2Vincr2]

Do a dc transfer curve analysis. See the previous sections of this manual for more details.

5.3.10.Define:Defineafunction

GeneralForm

define function(arg1, arg2, ...) expression

Define theuser-definablefunctionwith the namefunctionand argumentsarg1,arg2, ... to beexpression, which may involve the arguments. When the function is later used, the arguments it is given are substituted for the formal arguments when it is parsed. Ifexpres-sionis not present, any definition forfunctionis printed, and if there are no arguments todefinethen all currently active definitions are printed. Note that you may have different functions defined with the same name but different arities.

Some useful definitions are:

define max(x,y) (x > y) * x + (x <= y) * y define min(x,y) (x < y) * x + (x >= y) * y

5.3.11.Delete*:Removeatraceorbreakpoint

GeneralForm

delete [debug-number... ]

Delete the specified breakpoints and traces. The debug numbers are those shown by the status command (un- less you do status > file, in which case the debug numbers are not printed).

5.3.12.Diff:Comparevectors

GeneralForm

diff plot1 plot2 [vec ...]

Compare all the vectors in the specifiedplots, or only the named vectors if any are given. There are dif- ferent vectors in the two plots, or any values in the vectors differ significantly the difference is reported. The variable diff_abstol, diff_reltol, and diff_vntol are used to determine a significant difference.

5.3.13.Display:Listknownvectorsandtypes

GeneralForm

display [varname ...]

Prints a summary of currently defined vectors, or of the names specified. The vectors are sorted by name unless the variable nosort is set. The information given is the name of the vector, the length, the type of the vector, and whether it is real or complex data. Ad- ditionally, one vector is labeled [scale]. When a com- mand such asplotis given without avsargument, this scale is used for the X-axis. It is always the first vector in a rawfile, or the first vector defined in a new plot. If you undefine the scale (i.e,letTIME= []), one of the remaining vectors becomes the new scale (which is undetermined).

5.3.14.Echo:text

GeneralForm

echo [text...]

Echos the given text to the screen.

5.3.15.Edit*:Editthecurrentcircuit

GeneralForm

edit [file]

Print the current Spice3 input file into a file, call up the editor on that file and allow the user to modify it, and then read it back in, replacing the ori- ginal file. If afilenameis given, then edit that file and load it, making the circuit the current one.

5.3.16.Fourier:Performafouriertransform

GeneralForm

fourier fundamental_frequency [value ...]

Does a fourier analysis of each of the given values, using the first 10 multiples of the fundamental frequency (or the firstnfreqs, if that variable is set - see below). The output is like that of the .four Spice3 line. The values may be any valid expression. The values are interpolated onto a fixed-space grid with the number of points given by the fourgridsize variable, or 200 if it is not set. The interpolation is of degree polydegree if that variable is set, or 1. If polydegree is 0, then no interpolation is done. This is likely to give erroneous results if the time scale is not monoton- ic, though.

5.3.17.Hardcopy:Saveaplottoafileforprinting

GeneralForm

hardcopy fileplotargs

Just like plot, except creates a file calledfilecontaining the plot. The file is an image inplot(5) format, and can be printed by either the plot(1) program or lpr with the -g flag.

5.3.18.Help:summariesofSpice3commands

GeneralForm

help [all] [command ...]

Prints help. If the argument all is given, a short description of everything you could possibly type is printed. If commands are given, descriptions of those commands are printed. Otherwise help for only a few ma- jor commands is printed.

5.3.19.History:Reviewpreviouscommands

GeneralForm

history [number]

Print out the history, or the last number commands typed at the keyboard.Note: in Spice3 version 3a7 and earlier, all commands (including ones read from files) were saved.

5.3.20.Iplot*:Incrementalplot

GeneralForm

iplot [ node ...]

Incrementally plot the values of the nodes while Spice3 runs. The iplot command can be used with the where command to find trouble spots in a transient simu- lation.

5.3.21.Jobs:Listactiveasynchronousspiceruns

GeneralForm

jobs

Report on the asynchronous SPICE-3 jobs currently running. Nutmeg checks to see if the jobs are finished every time you execute a command. If it is done then the data is loaded and becomes available.

5.3.22.Let:Assignavaluetoavector

GeneralForm

let name = expr

Creates a new vector callednamewith the value specified byexpr, an expression as described above. If expr is [] (a zero-length vector) then the vector be- comes undefined. Individual elements of a vector may be modified by appending a subscript to name (ex. name[0]). If there are no arguments, let is the same as display.

5.3.23.Linearize*:Interpolatetoalinearscale

GeneralForm

linearize vec ...

Create a new plot with all of the vectors in the current plot, or only those mentioned if arguments are given. The new vectors are interpolated onto a linear time scale, which is determined by the values of tstep, tstart, and tstop in the currently active transient analysis. The currently loaded input file must include a transient analysis (a tran command may be run interac- tively before the last reset, alternately), and the current plot must be from this transient analysis. This command is needed because Spice3 doesn't output the results from a transient analysis in the same manner that Spice2 did.

5.3.24.Listing*:alistingofthecurrentcircuit

GeneralForm

listing [logical] [physical] [deck] [expand]

If the logical argument is given, the listing is with all continuation lines collapsed into one line, and if the physical argument is given the lines are printed out as they were found in the file. The default is log- ical. A deck listing is just like the physical listing, except without the line numbers it recreates the input file verbatim (except that it does not preserve case). If the word expand is present, the circuit is printed with all subcircuits expanded.

5.3.25.Load:Loadrawfiledata

GeneralForm

load [filename] ...

Loads either binary or ascii format rawfile data from the files named. The default filename is rawspice.raw, or the argument to the -r flag if there was one.

5.3.26.Op*:Performanoperatingpointanalysis

GeneralForm

op

Do an operating point analysis. See the previous sections of this manual for more details.

5.3.27.Plot:Plotvaluesonthedisplay

GeneralForm

plot exprs [ylimit ylo yhi] [xlimit xlo xhi] [xindices xilo xihi] [xcompress comp] [xdelta xdel] [ydelta ydel] [xlog] [ylog] [loglog] [vs xname] [xlabel word] [ylabel word] [title word] [samep] [linear]

Plot the givenexprson the screen (if you are on a graphics terminal). Thexlimitandylimitarguments deter- mine the high and low x- and y-limits of the axes, respec- tively. Thexindicesarguments determine what range of points are to be plotted - everything between the xilo'th point and the xihi'th point is plotted. Thexcompressargu- ment specifies that only one out of every comp points should be plotted. If an xdelta or a ydelta parameter is present, it specifies the spacing between grid lines on the X- and Y-axis. These parameter names may be abbreviated toxl,yl,xind,xcomp,xdel, andydelrespectively.

Thexnameargument is an expression to use as the scale on the x-axis. If xlog or ylog are present then the X or Y scale, respectively, is logarithmic (loglog is the same as specifying both). The xlabel and ylabel arguments cause the specified labels to be used for the X and Y axes, respec- tively.

If samep is given, the values of the other parameters (other than xname) from the previous plot, hardcopy, or asciiplot command is used unless re-defined on the command line.

The title argument is used in the place of the plot name at the bottom of the graph.

The linear keyword is used to override a default log- scale plot (as in the output for an AC analysis).

Finally, the keyword polar to generate a polar plot. To produce a smith plot, use the keyword smith. Note that the data is transformed, so for smith plots you will see the data transformed by the function (x-1)/(x+1). To produce a polar plot with a smith grid but without performing the smith transform, use the keyword smithgrid.

5.3.28.values

GeneralForm

print [col] [line] expr ...

Prints the vector described by the expressionexpr. If thecolargument is present, print the vectors named side by side. If line is given, the vectors are printed horizontally. col is the default, unless all the vec- tors named have a length of one, in which case line is the default. The options width, length, and nobreak are effective for this command (see asciiplot). If the ex- pression is all, all of the vectors available are print- ed. Thus print col all > file prints everything in the file in SPICE2 format. The scale vector (time, frequen- cy) is always in the first column unless the variable noprintscale is true.

5.3.29.Quit:LeaveSpice3orNutmeg

GeneralForm

quit

Quit nutmeg or spice.

5.3.30.Rehash:Resetinternalhashtables

GeneralForm

rehash

Recalculate the internal hash tables used when looking up UNIX commands, and make all UNIX commands in the user's PATH available for command completion. This is useless unless you have set unixcom first (see above).

5.3.31.Reset*:Resetananalysis

GeneralForm

reset

Throw out any intermediate data in the circuit (e.g, after a breakpoint or after one or more analyses have been done already), and re-parse the input file. The circuit can then be re-run from it's initial state, overriding the affect of any set or alter commands. In Spice-3e and earlier versions this was done automatical- ly by the run command.

5.3.32.Reshape:Alterthedimensionalityordimensionsofavector

GeneralForm

reshapevectorvector... or reshapevectorvector... [dimension,dimension, ... ] or reshapevectorvector... [dimension][dimension] ...

This command changes the dimensions of a vector or a set of vectors. The final dimension may be left off and it will be filled in automatically. If no dimen- sions are specified, then the dimensions of the first vector are copied to the other vectors. An error mes- sage of the form 'dimensions ofxwere inconsistent' can be ignored.

5.3.33.Resume*:Continueasimulationafterastop

GeneralForm

resume

Resume a simulation after a stop or interruption (control-C).

5.3.34.Rspice:Remotespicesubmission

GeneralForm

rspiceinputfile

Runs a SPICE-3 remotely taking the input file as a SPICE-3 input file, or the current circuit if no argu- ment is given. Nutmeg or Spice3 waits for the job to complete, and passes output from the remote job to the user's standard output. When the job is finished the data is loaded in as with aspice. If the variablerhostis set, nutmeg connects to this host instead of the de- fault remote Spice3 server machine. This command uses the "rsh" command and thereby requires authentication via a ".rhosts" file or other equivalent method. Note that "rsh" refers to the "remote shell" program, which may be "remsh" on your system; to override the default name of "rsh", set the variableremote_shell. If the variablerprogramis set, then rspice uses this as the pathname to the program to run on the remote system.

Note: rspice will not acknowledge elements that have been changed via the "alter" or "altermod" com- mands.

5.3.35.Run*:Runanalysisfromtheinputfile

GeneralForm

run [rawfile]

Run the simulation as specified in the input file. If there were any of the control lines .ac, .op, .tran, or .dc, they are executed. The output is put in rawfile if it was given, in addition to being available interac- tively. In Spice-3e and earlier versions, the input file would be re-read and any affects of the set or alter commands would be reversed. This is no longer the affect.

5.3.36.Rusage:Resourceusage

GeneralForm

rusage [resource ...]

Print resource usage statistics. If any resources are given, just print the usage of that resource. Most resources require that a circuit be loaded. Currently valid resources are:

elapsed The amount of time elapsed since the last rusage elaped call. faults Number of page faults and context switches (BSD only). space Data space used. time CPU time used so far.

temp Operating temperature. tnom Temperature at which device parameters were measured. equations Circuit Equations

time Total Analysis Time totiter Total iterations accept Accepted timepoints rejected Rejected timepoints

loadtime Time spent loading the circuit matrix and RHS. reordertime Matrix reordering time lutime L-U decomposition time solvetime Matrix solve time

trantime Transient analysis time tranpoints Transient timepoints traniter Transient iterations trancuriters Transient iterations for the last time point* tranlutime Transient L-U decomposition time transolvetime Transient matrix solve time

everything All of the above.

* listed incorrectly as "Transient iterations per point".

5.3.37.Save*:Saveasetofoutputs

GeneralForm

save [all |output...] .save [all |output...]

Save a set of outputs, discarding the rest. If a node has been mentioned in a save command, it appears in the working plot after a run has completed, or in the rawfile if spice is run in batch mode. If a node is traced or plotted (see below) it is also saved. For backward compatibility, if there are no save commands given, all outputs are saved.

When the keyword "all" appears in the save command, all default values (node voltages and voltage source currents) are saved in addition to any other values listed.

5.3.38.Sens*:Runasensitivityanalysis

GeneralForm

sensoutput_variablesensoutput_variableac ( DEC | OCT | LIN )NFstartFstop

Perform a Sensitivity analysis.output_variableis either a node voltage (ex. "v(1)" or "v(A,out)") or a current through a voltage source (ex. "i(vtest)"). The first form calculates DC sensitivities, the second form calculates AC sensitivies. The output values are in di- mensions of change in output per unit change of input (as opposed to percent change in output or per percent change of input).

5.3.39.Set:Setthevalueofavariable

GeneralForm

set [word] set [word = value] ...

Set the value of word to be value, if it is present. You can set any word to be any value, numeric or string. If no value is given then the value is the boolean 'true'.

The value ofwordmay be inserted into a command by writing $word. If a variable is set to a list of values that are enclosed in parentheses (which must be separated from their values by white space), the value of the variable is the list.

The variables used by nutmeg are listed in the follow- ing section.

5.3.40.Setcirc*:Changethecurrentcircuit

GeneralForm

setcirc [circuit name]

The current circuit is the one that is used for the simulation commands below. When a circuit is loaded with the source command (see below) it becomes the current circuit.

5.3.41.Setplot:Switchthecurrentsetofvectors

GeneralForm

setplot [plotname]

Set the current plot to the plot with the given name, or if no name is given, prompt the user with a menu. (Note that the plots are named as they are loaded, with names like tran1 or op2. These names are shown by the setplot and display commands and are used by diff, below.) If the "New plot" item is selected, the current plot becomes one with no vectors defined.

Note that here the word "plot" refers to a group of vectors that are the result of one SPICE run. When more than one file is loaded in, or more than one plot is present in one file, nutmeg keeps them separate and only shows you the vectors in the current plot.

5.3.42.Settype:Setthetypeofavector

GeneralForm

settype type vector ...

Change the type of the named vectors to type. Type names can be found in the manual page for sconvert.

5.3.43.Shell:Callthecommandinterpreter

GeneralForm

shell [command]

Call the operating system's command interpreter; execute the specified command or call for interactive use.

5.3.44.Shift:Alteralistvariable

GeneralForm

shift [varname] [number]

Ifvarnameis the name of a list variable, it is shifted to the left bynumberelements (i.e, thenumberleftmost elements are removed). The defaultvarnameis argv, and the defaultnumberis 1.

5.3.45.Show*:Listdevicestate

GeneralForm

showdevices[ :parameters] , ...

OldForm

show -v @device[ [name] ]

The show command prints out tables summarizing the operating condition of selected devices (much like the spice2 operation point summary). Ifdeviceis missing, a default set of devices are listed, ifdeviceis a sin- gle letter, devices of that type are listed; ifdeviceis a subcircuit name (beginning and ending in ":") only devices in that subcircuit are shown (end the name in a double-":" to get devices within sub-subcircuits recur- sively). The second and third forms may be combined ("letter:subcircuit:") or "letter:subcircuit::") to select a specific type of device from a subcircuit. A device's full name may be specified to list only that device. Finally, devices may be selected by model by using the form "#modelname" or ":subcircuit#modelname" or "letter:subcircuit#modelname".

If noparametersare specified, the values for a standard set of parameters are listed. If the list ofparameterscontains a "+", the default set of parameters is listed along with any other specified parameters.

For bothdevicesandparameters, the word "all" has the obvious meaning. Note: there must be spaces separating the ":" that divides thedevicelist from theparameterlist.

The "old form" (with "-v") prints the data in a older, more verbose pre-spice3f format.

5.3.46.Showmod*:Listmodelparametervalues

GeneralForm

showmodmodels[ :parameters] , ...

The showmod command operates like the show command (above) but prints out model parameter values. The ap- plicable forms formodelsare a single letter specifying the device type letter, "letter:subckt:", "modelname", ":subckt:modelname", or "letter:subcircuit:modelname".

5.3.47.Source:ReadaSpice3inputfile

GeneralForm

sourcefile

For Spice3: Read the Spice3 input file file. Nut- meg and Spice3 commands may be included in the file, and must be enclosed between the lines .controland .endc. These commands are executed immediately after the cir- cuit is loaded, so a control line ofac... works the same as the corresponding .accard. The first line in any input file is considered a title line and not parsed but kept as the name of the circuit. The exception to this rule is the file .spiceinit. Thus, a Spice3 com- mand script must begin with a blank line and then with a acters *# is considered a control line. This makes it possible to imbed commands in Spice3 input files that are ignored by earlier versions of Spice2

For Nutmeg: Reads commands from the filefilename. Lines beginning with the character * are considered com- ments and ignored.

5.3.48.Status*:Displaybreakpointinformation

GeneralForm

status

Display all of the traces and breakpoints currently in effect.

5.3.49.Step*:Runafixednumberoftimepoints

GeneralForm

step [number]

Iterate number times, or once, and then stop.

5.3.50.Stop*:Setabreakpoint

GeneralForm

stop [ after n] [ whenvaluecondvalue] ...

Set a breakpoint. The argument after n means stop after n iteration number n, and the argument whenvaluecondvaluemeans stop when the firstvalueis in the given relation with the secondvalue, the possible rela- tions being

eq or = equal to ne or <> not equal to gt or > greater than lt or < less than ge or >= greater than or equal to le or <= less than or equal to

IO redirection is disabled for the stop command, since the relational operations conflict with it (it doesn't produce any output anyway). Thevalues above may be node names in the running circuit, or real values. If more than one con- dition is given, e.g. stop after 4 when v(1) > 4 when v(2) < 2, the conjunction of the conditions is implied.

5.3.51.Tf*:RunaTransferFunctionanalysis

GeneralForm

tfoutput_nodeinput_source

The tf command performs a transfer function analysis, returning the transfer function (output/input), output resistance, and input resistance between the given output node and the given input source. The analysis assumes a small-signal DC (slowly varying) input.

5.3.52.Trace*:Tracenodes

GeneralForm

trace [ node ...]

For every step of an analysis, the value of the node is printed. Several traces may be active at once. Tracing is not applicable for all analyses. To remove a trace, use the delete command.

5.3.53.Tran*:Performatransientanalysis

GeneralForm

tranTstepTstop[Tstart[Tmax] ] [ UIC ]

Perform a transient analysis. See the previous sections of this manual for more details.

5.3.54.Transpose:Swaptheelementsinamulti-dimensionaldataset

GeneralForm

transposevectorvector...

This command transposes a multidimensional vector. No analysis in Spice3 produces multidimensional vectors, although the DC transfer curve may be run with two vary- ing sources. You must use the "reshape" command to re- form the one-dimensional vectors into two dimensional vectors. In addition, the default scale is incorrect for plotting. You must plot versus the vector corresponding to the second source, but you must also refer only to the first segment of this second source vector. For example (circuit to produce the tranfer characteristic of a MOS transistor):

spice3 > dc vgg 0 5 1 vdd 0 5 1 spice3 > plot i(vdd) spice3 > reshape all [6,6] spice3 > transpose i(vdd) v(drain) spice3 > plot i(vdd) vs v(drain)[0]

5.3.55.Unalias:Retractanalias

GeneralForm

unalias [word ...]

Removes any aliases present for the words.

5.3.56.Undefine:Retractadefinition

GeneralForm

undefine function

Definitions for the named user-defined functions are deleted.

5.3.57.Unset:Clearavariable

GeneralForm

unset [word...]

Clear the value of the specified variable(s) (word).

5.3.58.Version:theversionofSpice

GeneralForm

version [version id]

Print out the version of nutmeg that is running. If there are arguments, it checks to make sure that the arguments match the current version of SPICE. (This is mainly used as a Command: line in rawfiles.)

5.3.59.Where:Identifytroublesomenodeordevice

GeneralForm

where

When performing a transient or operating point analysis, the name of the last node or device to cause non-convergence is saved. The where command prints out this information so that you can examine the circuit and either correct the problem or make a bug report. You may do this either in the middle of a run or after the simulator has given up on the analysis. For transient simulation, the iplot command can be used to monitor the progress of the analysis. When the analysis slows down severly or hangs, interrupt the simulator (with control-C) and issue the where command. Note that only one node or device is printed; there may be problems with more than one node.

5.3.60.Write:Writedatatoafile

GeneralForm

write [file] [exprs]

Writes out the expressions tofile.

First vectors are grouped together by plots, and written out as such (i.e, if the expression list con- tained three vectors from one plot and two from another, then two plots are written, one with three vectors and one with two). Additionally, if the scale for a vector isn't present, it is automatically written out as well.

The default format is ascii, but this can be changed with the set filetype command. The default filename is rawspice.raw, or the argument to the -r flag on the command line, if there was one, and the default expression list is all.

5.3.61.Xgraph:usethexgraph(1)programforplotting.

GeneralForm

xgraphfile[exprs] [plot options]

The spice3/nutmeg xgraph command plots data like the plot command but via xgraph, a popular X11 plotting program.

Iffileis either "temp" or "tmp" a temporary file is used to hold the data while being plotted. For available plot options, see the plot command. All op- tions except for polar or smith plots are supported.

5.4.CONTROLSTRUCTURES

While End | Foreach End | Goto | |

Repeat End | If Then Else | Continue | |

Dowhile End | Label | Break |

5.4.1.While-End

GeneralForm

whileconditionstatement ... end

Whilecondition, an arbitrary algebraic expression, is true, execute the statements.

5.4.2.Repeat-End

GeneralForm

repeat [number] statement ... end

Execute the statementsnumbertimes, or forever if no argument is given.

5.4.3.Dowhile-End

GeneralForm

dowhileconditionstatement ... end

The same as while, except that theconditionis tested after the statements are executed.

5.4.4.Foreach-End

GeneralForm

foreachvarvalue... statement ... end

The statements are executed once for each of thevalues, each time with the variablevarset to the current one. (varcan be accessed by the $varnotation - see below).

5.4.5.If-Then-Else

GeneralForm

ifconditionstatement ... else statement ... end

If theconditionis non-zero then the first set of statements are executed, otherwise the second set. The else and the second set of statements may be omitted.

5.4.6.Label

GeneralForm

labelword

If a statement of the form gotowordis encoun- tered, control is transferred to this point, otherwise this is a no-op.

5.4.7.Goto

GeneralForm

gotoword

If a statement of the form labelwordis present in the block or an enclosing block, control is transferred there. Note that if the label is at the top level, itmustbe before the gotostatement(i.e,aforwardgotomay occur only within a block).

5.4.8.ContinueGeneralForm

continue

If there is a while, dowhile, or foreach block en- closing this statement, control passes to the test, or in the case of foreach, the next value is taken. Other- wise an error results.

5.4.9.Break

GeneralForm

break

If there is a while, dowhile, or foreach block en- closing this statement, control passes out of the block. Otherwise an error results.

Of course, control structures may be nested. When a block is entered and the input is the terminal, the prompt becomes a number of >'s corresponding to the number of blocks the user has entered. The current con- trol structures may be examined with the debugging com- mandcdump.

5.5.VARIABLES

The operation of both Nutmeg and Spice3 may be affected by setting variables with the "set" command. In addition to the variables mentioned below, the set command in Spice3 also affect the behaviour of the simulator via the options previously described under the section on ".OPTIONS".

The variables meaningful to nutmeg which may be altered by the set command are:

diff_abstol The absolute tolerance used by the diff command. appendwrite Append to the file when a write command is is- sued, if one already exists. colorNThese variables determine the colors used, if X is being run on a color display.Nmay be between 0 and 15. Color 0 is the background, color 1 is the grid and text color, and colors 2 through 15 are used in order for vectors plot- ted. The value of the color variables should be names of colors, which may be found in the file /usr/lib/rgb.txt. combplot Plot vectors by drawing a vertical line from each point to the X-axis, as opposed to joining the points. Note that this option is subsumed in theplottypeoption, below. cpdebug Printcshpardebugging information (must be com- plied with the -DCPDEBUG flag). Unsupported in the current release.

debug If set then a lot of debugging information is printed (must be compiled with the -DFTEDEBUG flag). Unsupported in the current release. device The name (/dev/tty??) of the graphics device. If this variable isn't set then the user's terminal is used. To do plotting on another monitor you probably have to set both the device and term variables. (If device is set to the name of a file, nutmeg dumps the graphics control codes into this file -- this is useful for saving plots.) echo Print out each command before it is executed. filetype This can be eitherasciiorbinary, and determines what format are. The default isascii.

fourgridsize How many points to use for interpolating into when doing fourier analysis. gridsize If this variable is set to an integer, this number is used as the number of equally spaced points to use for the Y- axis when plotting. Otherwise the current scale is used (which may not have equally spaced points). If the current scale isn't strictly monotonic, then this option has no effect. hcopydev If this is set, when the hardcopy com- mand is run the resulting file is au- tomatically printed on the printer named hcopydev with the commandlpr-Phcopydev -gfile.

hcopyfont This variable specifies the font name for hardcopy output plots. The value is device dependent. hcopyfontsize This is a scaling factor for the font used in hardcopy plots. hcopydevtype This variable specifies the type of the printer output to use in the hardcopy command. If hcopydevtype is not set, plot (5) format is assumed. The stan- dard distribution currently recognizes postscript as an alternative output for- mat. When used in conjunction with hcopydev, hcopydevtype should specify a format supported by the printer. height The length of the page for asciiplot and print col. history The number of events to save in the his- tory list. lprplot5 This is a printf(3s) style format string used to specify the command to use for sending plot(5)-style plots to a printer or plotter. The first parameter sup- plied is the printer name, the second parameter supplied is a file name con- taining the plot. Both parameters are strings. It is trivial to cause Spice3 to abort by supplying a unreasonable format string. lprps This is a printf(3s) style format string used to specify the command to use for sending PostScript plots to a printer or plotter. The first parameter supplied is the printer name, the second parame- ter supplied is a file name containing the plot. Both parameters are strings. It is trivial to cause Spice3 to abort by supplying a unreasonable format string. nfreqs The number of frequencies to compute in thefouriercommand. (Defaults to 10.) nobreak Don't have asciiplot and print col break between pages.

noasciiplotvalue Don't print the first vector plotted to the left when doing an asciiplot. noclobber Don't overwrite existing files when do- ing IO redirection. noglob Don't expand the global characters `*', `?', `[', and `]'. This is the default. nogrid Don't plot a grid when graphing curves (but do label the axes). nomoremode If nomoremode is not set, whenever a large amount of data is being printed to the screen (e.g, the print or asciiplot commands), the output is stopped every screenful and continues when a carriage return is typed. If nomoremode is set then data scrolls off the screen without check. nonomatch If noglob is unset and a global expres- sion cannot be matched, use the global characters literally instead of com- plaining.

nosort Don't have display sort the variable names. noprintscale Don't print the scale in the leftmost column when a print col command is given. numdgt The number of digits to print when printing tables of data (fourier, print col). The default precision is 6 digits. On the VAX, approximately 16 decimal digits are avail- able using double precision, so numdgt should not be more than 16. If the number is negative, one fewer digit is printed to ensure constant widths in tables. plottype This should be one of normal, comb, or point:chars. normal, the default, causes points to be plotted as parts of connected lines. comb causes a comb plot to be done (see the description of the combplot vari- able above). point causes each point to be plotted separately - the chars are a list of characters that are used for each vector plotted. If they are omitted then a de- fault set is used. polydegree The degree of the polynomial that the plot command should fit to the data. Ifpolyde-greeis N, then nutmeg fits a degree N po- lynomial to every set of N points and draw 10 intermediate points in between each end- point. If the points aren't monotonic, then it tries rotating the curve and reduc- ing the degree until a fit is achieved. polysteps The number of points to interpolate between every pair of points available when doing curve fitting. The default is 10. program The name of the current program (argv[0]). prompt The prompt, with the character `!' replaced by the current event number.

rawfile The default name for rawfiles created. diff_reltol The relative tolerance used by the diff command. remote_shell Overrides the name used for generating rspice runs (default is "rsh"). rhost The machine to use for remote SPICE-3 runs, in- stead of the default one (see the description of the rspice command, below). rprogram The name of the remote program to use in the rspice command. slowplot Stop between each graph plotted and wait for the user to type return before continuing. sourcepath A list of the directories to search when a source command is given. The default is the current directory and the standard spice library (/usr/local/lib/spice, or whatever LIBPATH is #defined to in the Spice3 source. spicepath The program to use for the aspice command. The default is /cad/bin/spice. term Themfbname of the current terminal. units If this is degrees, then all the trig functions will use degrees instead of radians. unixcom If a command isn't defined, try to execute it as a UNIX command. Setting this option has the ef- fect of giving a rehash command, below. This is useful for people who want to use nutmeg as a login shell. verbose Be verbose. This is midway between echo and de- bug / cpdebug. diff_vntol The absolute voltage tolerance used by the diff command.

width The width of the page for asciiplot and print col. x11lineararcs Some X11 implementations have poor arc drawing. If you set this option, Spice3 will plot using an approximation to the curve using straight lines. xbrushheight The height of the brush to use if X is being run. xbrushwidth The width of the brush to use if X is being run. xfont The name of the X font to use when plot- ting data and entering labels. The plot may not look good if this is a variable-width font.

There are several set variables that Spice3 uses but Nutmeg does not. They are:

editor The editor to use for the edit command. modelcard The name of the model card (normally May.in -432u noaskquit Do not check to make sure that there are no circuits suspended and no plots un- saved. Normally Spice3 warns the user when he tries to quit if this is the case. nobjthack Assume that BJTs have 4 nodes. noparse Don't attempt to parse input files when they are read in (useful for debugging). Of course, they cannot be run if they are not parsed. nosubckt Don't expand subcircuits. renumber Renumber input lines when an input file has .include's. subend The card to end subcircuits (normally subinvoke The prefix to invoke subcircuits (nor- mally x). substart The card to begin subcircuits (normally

5.6.MISCELLANEOUS

If there are subcircuits in the input file, Spice3 expands instances of them. A subcircuit is delimited by the cards .subcktand .ends, or whatever the value of the vari- ablessubstartandsubendis, respectively. An instance of a subcircuit is created by specifying a device with type 'x' - the device line is written

xname node1 node2 ... subcktname

where the nodes are the node names that replace the formal parameters on the .subckt line. All nodes that are not for- mal parameters are prepended with the name given to the instance and a ':', as are the names of the devices in the subcircuit. If there are several nested subcircuits, node and device names look like subckt1:subckt2:...:name. If the variable subinvoke is set, then it is used as the prefix that specifies instances of subcircuits, instead of 'x'.

Nutmeg occasionally checks to see if it is getting close to running out of space, and warns the user if this is the case. (This is more likely to be useful with the SPICE front end.)

C-shell type quoting with "" and '', and backquote sub- stitution may be used. Within single quotes, no further substitution (like history substitution) is done, and within double quotes, the words are kept together but further sub- stitution is done. Any text between backquotes is replaced by the result of executing the text as a command to the shell.

Tenex-style ('set filec' in the 4.3 C-shell) command, filename, and keyword completion is possible: If EOF (control-D) is typed after the first character on the line, a list of the commands or possible arguments is printed (If it is alone on the line it exits nutmeg). If escape is typed, then nutmeg trys to complete what the user has already typed. To get a list of all commands, the user should type <space> ^D.

The values of variables may be used in commands by writing $varname where the value of the variable is to appear. The special variables $$ and $< refer to the pro- cess ID of the program and a line of input which is read from the terminal when the variable is evaluated, respec- tively. If a variable has a name of the form $&word, then word is considered a vector (see above), and its value is taken to be the value of the variable. If $foois a valid variable, and is of type list, then the expression $foo[low-high] represents a range of elements. Either the upper index or the lower may be left out, and the reverse of a list may be obtained with $foo[len-0]. Also, the notation $?fooevaluates to 1 if the variablefoois defined, 0 oth- erwise, and $#fooevaluates to the number of elements infooif it is a list, 1 if it is a number or string, and 0 if it is a boolean variable.

History substitutions, similar to C-shell history sub- stitutions, are also available - see the C-shell manual page for all of the details.

The characters ~, {, and } have the same effects as they do in the C-Shell, i.e., home directory and alternative expansion. It is possible to use the wildcard characters *, ?, [, and ] also, but only if you unset noglob first. This makes them rather useless for typing algebraic expressions, so you should set noglob again after you are done with wild- card expansion. Note that the pattern [^abc] matchs all charactersexcepta, b,andc.

IO redirection is available - the symbols >, >>, >&, >>&, and < have the same effects as in the C-shell.

You may type multiple commands on one line, separated by semicolons.

If you want to use a different mfbcap file than the default (usually ~cad/lib/mfbcap), you have to set the environment variable SPICE_MFBCAP before you start nutmeg or spice. The -m option and the mfbcap variable no longer work.

If X is being used, the cursor may be positioned at any point on the screen when the window is up and characters typed at the keyboard are added to the window at that point. The window may then be sent to a printer using the xpr(1) program.

Nutmeg can be run under VAX/VMS, as well as several other operating systems. Some features like command comple- tion, expansion of *, ?, and [], backquote substitution, the shell command, and so forth do not work.

On some systems you have to respond to the -more- prompt during plot with a carriage return instead of any key as you can do on UNIX.

5.7.BUGS

The label entry facilities are primitive. You must be careful to type slowly when entering labels -- nutmeg checks for input once every second, and can get confused if charac- ters arrive faster.

If you redefine colors after creating a plot window with X, and then cause the window to be redrawn, it does not redraw in the correct colors.

When defining aliases like

alias pdb plot db( '!:1' - '!:2' )

you must be careful to quote the argument list substitu- tions in this manner. If you quote the whole argument it might not work properly.

In a user-defined function, the arguments cannot be part of a name that uses theplot.vecsyntax. For example:

define check(v(1)) cos(tran1.v(1))

does not work.

If you type plot all all, or otherwise use a wildcard reference for one plot twice in a command, the effect is unpredictable.

The asciiplot command doesn't deal with log scales or the delta keywords.

Often the names of terminals recognized by MFB are dif- ferent from those in /etc/termcap. Thus you may have to reset your terminal type with the command

set term = termname

where termname is the name in the mfbcap file.

The hardcopy command is useless on VMS and other sys- tems without the plot command, unless the user has a program that understandsplot(5) format.

Spice3 recognizes all the notations used in SPICE2 .plot cards, and translates vp(1) into ph(v(1)), and so forth. However, if there are spaces in these names it won't work. Hence v(1, 2) and (-.5, .5) aren't recognized.

BJTs can have either 3 or 4 nodes, which makes it dif- ficult for the subcircuit expansion routines to decide what to rename. If the fourth parameter has been declared as a model name, then it is assumed that there are 3 nodes, oth- erwise it is considered a node. To disable this, you can set the variable "nobjthack" which forces BJTs to have 4 nodes (for the purposes of subcircuit expansion, at least).

The @name[param] notation might not work with trace, iplot, etc. yet.

The first line of a command file (except for the .spi-ceinitfile) should be a comment, otherwise SPICE may create an empty circuit.

Files specified on the command line are read before .spiceinit is read.

6.BIBLIOGRAPHY

[1] A. Vladimirescu and S. Liu,TheSimulationofMOSIntegratedCircuitsUsingSPICE2ERL Memo No. ERL M80/7, Electronics Research Laboratory University of California, Berkeley, October 1980

[2] T. Sakurai and A. R. Newton,ASimpleMOSFETModelforCircuitAnalysisanditsapplicationtoCMOSgatedelayanalysisandseries-connectedMOSFETStructureERL Memo No. ERL M90/19, Electronics Research Labora- tory, University of California, Berkeley, March 1990

[3] B. J. Sheu, D. L. Scharfetter, and P. K. Ko,SPICE2ImplementationofBSIMERL Memo No. ERL M85/42, Electronics Research Labora- tory University of California, Berkeley, May 1985

[4] J. R. Pierret,AMOSParameterExtractionProgramfortheBSIMModelERL Memo Nos. ERL M84/99 and M84/100, Electronics Research Laboratory University of California, Berkeley, November 1984

[5] Min-Chie Jeng,DesignandModelingofDeep-SubmicrometerMOSFETSsERL Memo Nos. ERL M90/90, Electronics Research Labora- tory University of California, Berkeley, October 1990

[6] Soyeon Park,AnalysisandSPICEimplementationofHighTemperatureEffectsonMOSFET, Master's thesis, University of California, Berkeley, December 1986.

[7] Clement Szeto,SimulatorofTemperatureEffectsinMOS-FETs(STEIM), Master's thesis, University of California, Berkeley, May 1988.

[8] J.S. Roychowdhury and D.O. Pederson,EfficientTran-sientSimulationofLossyInterconnect, Proc. of the 28th ACM/IEEE Design Automation Confer- ence, June 17-21 1991, San Francisco

[9] A. E. Parker and D. J. Skellern,AnImprovedFETModelforComputerSimulators, IEEE Trans CAD, vol. 9, no. 5, pp. 551-553, May 1990.

[10] R. Saleh and A. Yang, Editors,SimulationandModeling, IEEE Circuits and Devices, vol. 8, no. 3, pp. 7-8 and 49, May 1992

[11] H.Statz et al.,GaAsFETDeviceandCircuitSimulationinSPICE, IEEE Transactions on Electron Devices, V34, Number 2, February, 1987 pp160-169.

A.APPENDIXA:EXAMPLECIRCUITS

Circuit 1 | Circuit 3 | Circuit 5 | |

Circuit 2 | Circuit 4 |

A.1.Circuit1:DifferentialPair

The following deck determines the dc operating point of a simple differential pair. In addition, the ac small-signal response is computed over the frequency range 1Hz to 100MEGHz.

SIMPLE DIFFERENTIAL PAIR VCC 7 0 12 VEE 8 0 -12 VIN 1 0 AC 1 RS1 1 2 1K RS2 6 0 1K Q1 3 2 4 MOD1 Q2 5 6 4 MOD1 RC1 7 3 10K RC2 7 5 10K RE 4 8 10K .MODEL MOD1 NPN BF=50 VAF=50 IS=1.E-12 RB=100 CJC=.5PF TF=.6NS .TF V(5) VIN .AC DEC 10 1 100MEG .END

A.2.Circuit2:MOSFETCharacterization

The following deck computes the output characteristics of a MOSFET device over the range 0-10V for VDS and 0-5V for VGS.

MOS OUTPUT CHARACTERISTICS .OPTIONS NODE NOPAGE VDS 3 0 VGS 2 0 M1 1 2 0 0 MOD1 L=4U W=6U AD=10P AS=10P * VIDS MEASURES ID, WE COULD HAVE USED VDS, BUT ID WOULD BE NEGATIVE VIDS 3 1 .MODEL MOD1 NMOS VTO=-2 NSUB=1.0E15 UO=550 .DC VDS 0 10 .5 VGS 0 5 1 .END

A.3.Circuit3:RTLInverter

The following deck determines the dc transfer curve and the transient pulse response of a simple RTL inverter. The input is a pulse from 0 to 5 Volts with delay, rise, and fall times of 2ns and a pulse width of 30ns. The transient interval is 0 to 100ns, with printing to be done every nanosecond.

SIMPLE RTL INVERTER VCC 4 0 5 VIN 1 0 PULSE 0 5 2NS 2NS 2NS 30NS RB 1 2 10K Q1 3 2 0 Q1 RC 3 4 1K .MODEL Q1 NPN BF 20 RB 100 TF .1NS CJC 2PF .DC VIN 0 5 0.1 .TRAN 1NS 100NS .END

A.4.Circuit4:Four-BitBinaryAdder

The following deck simulates a four-bit binary adder, using several subcircuits to describe various pieces of the overall circuit.

ADDER - 4 BIT ALL-NAND-GATE BINARY ADDER

*** SUBCIRCUIT DEFINITIONS .SUBCKT NAND 1 2 3 4 * NODES: INPUT(2), OUTPUT, VCC Q1 9 5 1 QMOD D1CLAMP 0 1 DMOD Q2 9 5 2 QMOD D2CLAMP 0 2 DMOD RB 4 5 4K R1 4 6 1.6K Q3 6 9 8 QMOD R2 8 0 1K RC 4 7 130 Q4 7 6 10 QMOD DVBEDROP 10 3 DMOD Q5 3 8 0 QMOD .ENDS NAND

.SUBCKT ONEBIT 1 2 3 4 5 6 * NODES: INPUT(2), CARRY-IN, OUTPUT, CARRY-OUT, VCC X1 1 2 7 6 NAND X2 1 7 8 6 NAND X3 2 7 9 6 NAND X4 8 9 10 6 NAND X5 3 10 11 6 NAND X6 3 11 12 6 NAND X7 10 11 13 6 NAND X8 12 13 4 6 NAND X9 11 7 5 6 NAND .ENDS ONEBIT

.SUBCKT TWOBIT 1 2 3 4 5 6 7 8 9 * NODES: INPUT - BIT0(2) / BIT1(2), OUTPUT - BIT0 / BIT1, * CARRY-IN, CARRY-OUT, VCC X1 1 2 7 5 10 9 ONEBIT X2 3 4 10 6 8 9 ONEBIT .ENDS TWOBIT

.SUBCKT FOURBIT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 * NODES: INPUT - BIT0(2) / BIT1(2) / BIT2(2) / BIT3(2), * OUTPUT - BIT0 / BIT1 / BIT2 / BIT3, CARRY-IN, CARRY-OUT, VCC X1 1 2 3 4 9 10 13 16 15 TWOBIT X2 5 6 7 8 11 12 16 14 15 TWOBIT .ENDS FOURBIT

*** DEFINE NOMINAL CIRCUIT .MODEL DMOD D .MODEL QMOD NPN(BF=75 RB=100 CJE=1PF CJC=3PF) VCC 99 0 DC 5V VIN1A 1 0 PULSE(0 3 0 10NS 10NS 10NS 50NS) VIN1B 2 0 PULSE(0 3 0 10NS 10NS 20NS 100NS) VIN2A 3 0 PULSE(0 3 0 10NS 10NS 40NS 200NS) VIN2B 4 0 PULSE(0 3 0 10NS 10NS 80NS 400NS) VIN3A 5 0 PULSE(0 3 0 10NS 10NS 160NS 800NS) VIN3B 6 0 PULSE(0 3 0 10NS 10NS 320NS 1600NS) VIN4A 7 0 PULSE(0 3 0 10NS 10NS 640NS 3200NS) VIN4B 8 0 PULSE(0 3 0 10NS 10NS 1280NS 6400NS) X1 1 2 3 4 5 6 7 8 9 10 11 12 0 13 99 FOURBIT RBIT0 9 0 1K RBIT1 10 0 1K RBIT2 11 0 1K RBIT3 12 0 1K RCOUT 13 0 1K

*** (FOR THOSE WITH MONEY (AND MEMORY) TO BURN) .TRAN 1NS 6400NS .END

A.5.Circuit5:Transmission-LineInverter

The following deck simulates a transmission-line in- verter. Two transmission-line elements are required since two propagation modes are excited. In the case of a coaxial line, the first line (T1) models the inner conductor with respect to the shield, and the second line (T2) models the shield with respect to the outside world.

TRANSMISSION-LINE INVERTER V1 1 0 PULSE(0 1 0 0.1N) R1 1 2 50 X1 2 0 0 4 TLINE R2 4 0 50

.SUBCKT TLINE 1 2 3 4 T1 1 2 3 4 Z0=50 TD=1.5NS T2 2 0 4 0 Z0=100 TD=1NS .ENDS TLINE

.TRAN 0.1NS 20NS .END

B.APPENDIXB:MODELANDDEVICEPARAMETERS

The following tables summarize the parameters available on each of the devices and models in (note that for some systems with limited memory, output parameters are not available). There are several tables for each type of dev- ice supported by . Input parameters to instances and models are parameters that can occur on an instance or model defin- ition line in the form "keyword=value" where "keyword" is the parameter name as given in the tables. Default input parameters (such as the resistance of a resistor or the capacitance of a capacitor) obviously do not need the key- word specified.

Output parameters are those additional parameters which are available for many types of instances for the output of operating point and debugging information. These parameters are specified as "@device[keyword]" and are available for the most recent point computed or, if specified in a ".save" statement, for an entire simulation as a normal output vec- tor. Thus, to monitor the gate-to-source capacitance of a MOSFET, a command

save @m1[cgs]

given before a transient simulation causes the specified capacitance value to be saved at each timepoint, and a sub- sequent command such as

plot @m1[cgs]

produces the desired plot. (Note that the show command does not use this format).

Some variables are listed as both input and output, and their output simply returns the previously input value, or the default value after the simulation has been run. Some parameter are input only because the output system can not handle variables of the given type yet, or the need for them as output variables has not been apparent. Many such input variables are available as output variables in a different format, such as the initial condition vectors that can be retrieved as individual initial condition values. Finally, internally derived values are output only and are provided for debugging and operating point output purposes.

Please note that these tables do not provide the detailed information available about the parameters provided in the section on each device and model, but are provided as a quick reference guide.

URC | CCVS | LTRA | Switch |

ASRC | CSwitch | MES | Tranline |

BJT | Diode | Mos1 | VCCS |

BSIM1 | Inductor | Mos2 | VCVS |

BSIM2 | mutual | Mos3 | Vsource |

Capacitor | Isource | Mos6 | |

CCCS | JFET | Resistor |

B.1.URC:UniformR.C.line------------------------------------------------------------ | URC - instance parameters (input-output) | |-----------------------------------------------------------+ | l Length of transmission line | | n Number of lumps | ------------------------------------------------------------

------------------------------------------------------------ | URC - instance parameters (output-only) | |-----------------------------------------------------------+ | pos_node Positive node of URC | | neg_node Negative node of URC | | gnd Ground node of URC | ------------------------------------------------------------

------------------------------------------------------------ | URC - model parameters (input-only) | |-----------------------------------------------------------+ | urc Uniform R.C. line model | ------------------------------------------------------------

------------------------------------------------------------ | URC - model parameters (input-output) | |-----------------------------------------------------------+ | k Propagation constant | | fmax Maximum frequency of interest | | rperl Resistance per unit length | | cperl Capacitance per unit length | | isperl Saturation current per length | | rsperl Diode resistance per length | ------------------------------------------------------------

B.2.ASRC:ArbitrarySource------------------------------------------------------------ | ASRC - instance parameters (input-only) | |-----------------------------------------------------------+ | i Current source | | v Voltage source | ------------------------------------------------------------

------------------------------------------------------------ | ASRC - instance parameters (output-only) | |-----------------------------------------------------------+ | i Current through source | | v Voltage across source | | pos_node Positive Node | | neg_node Negative Node | ------------------------------------------------------------

B.3.BJT:BipolarJunctionTransistor------------------------------------------------------------ | BJT - instance parameters (input-only) | |-----------------------------------------------------------+ | ic Initial condition vector | ------------------------------------------------------------

------------------------------------------------------------ | BJT - instance parameters (input-output) | |-----------------------------------------------------------+ | off Device initially off | | icvbe Initial B-E voltage | | icvce Initial C-E voltage | | area Area factor | | temp instance temperature | ------------------------------------------------------------

------------------------------------------------------------ | BJT - instance parameters (output-only) | |-----------------------------------------------------------+ | colnode Number of collector node | | basenode Number of base node | | emitnode Number of emitter node | | substnode Number of substrate node | ------------------------------------------------------------ | colprimenode Internal collector node | | baseprimenode Internal base node | | emitprimenode Internal emitter node | | ic Current at collector node | |-----------------------------------------------------------+ ib Current at base node | ie Emitter current | | is Substrate current | | vbe B-E voltage | ------------------------------------------------------------ | vbc B-C voltage | | gm Small signal transconductance | | gpi Small signal input conductance - pi | | gmu Small signal conductance - mu | |-----------------------------------------------------------+ | gx Conductance from base to internal base | | go Small signal output conductance | | geqcb d(Ibe)/d(Vbc) | | gccs Internal C-S cap. equiv. cond. | ------------------------------------------------------------ | geqbx Internal C-B-base cap. equiv. cond. | | cpi Internal base to emitter capactance | | cmu Internal base to collector capactiance | | cbx Base to collector capacitance | |-----------------------------------------------------------+ | ccs Collector to substrate capacitance | | cqbe Cap. due to charge storage in B-E jct. | | cqbc Cap. due to charge storage in B-C jct. | | cqcs Cap. due to charge storage in C-S jct. | | cqbx Cap. due to charge storage in B-X jct. | |continued| ------------------------------------------------------------

------------------------------------------------------------ | BJT - instance output-only parameters -continued|-----------------------------------------------------------+ | cexbc Total Capacitance in B-X junction | | qbe Charge storage B-E junction | | qbc Charge storage B-C junction | | qcs Charge storage C-S junction | | qbx Charge storage B-X junction | | p Power dissipation | ------------------------------------------------------------

------------------------------------------------------------ | BJT - model parameters (input-output) | |-----------------------------------------------------------+ | npn NPN type device | | pnp PNP type device | | is Saturation Current | | bf Ideal forward beta | ------------------------------------------------------------ | nf Forward emission coefficient | | vaf Forward Early voltage | | va (null) | | ikf Forward beta roll-off corner current | |-----------------------------------------------------------+ | ik (null) | | ise B-E leakage saturation current | | ne B-E leakage emission coefficient | | br Ideal reverse beta | ------------------------------------------------------------ | nr Reverse emission coefficient | | var Reverse Early voltage | | vb (null) | | ikr reverse beta roll-off corner current | |-----------------------------------------------------------+ | isc B-C leakage saturation current | | nc B-C leakage emission coefficient | | rb Zero bias base resistance | | irb Current for base resistance=(rb+rbm)/2 | ------------------------------------------------------------ | rbm Minimum base resistance | | re Emitter resistance | | rc Collector resistance | | cje Zero bias B-E depletion capacitance | |-----------------------------------------------------------+ | vje B-E built in potential | | pe (null) | | mje B-E junction grading coefficient | | me (null) | ------------------------------------------------------------ | tf Ideal forward transit time | | xtf Coefficient for bias dependence of TF | | vtf Voltage giving VBC dependence of TF | | itf High current dependence of TF | |-----------------------------------------------------------+ | ptf Excess phase | | cjc Zero bias B-C depletion capacitance | | vjc B-C built in potential | |continued| ------------------------------------------------------------

------------------------------------------------------------ | BJT - model input-output parameters -continued|-----------------------------------------------------------+ | pc (null) | | mjc B-C junction grading coefficient | | mc (null) | | xcjc Fraction of B-C cap to internal base | ------------------------------------------------------------ | tr Ideal reverse transit time | | cjs Zero bias C-S capacitance | | ccs Zero bias C-S capacitance | | vjs Substrate junction built in potential | |-----------------------------------------------------------+ | ps (null) | | mjs Substrate junction grading coefficient | | ms (null) | | xtb Forward and reverse beta temp. exp. | ------------------------------------------------------------ | eg Energy gap for IS temp. dependency | | xti Temp. exponent for IS | | fc Forward bias junction fit parameter | | tnom Parameter measurement temperature | | kf Flicker Noise Coefficient | | af Flicker Noise Exponent | ------------------------------------------------------------

------------------------------------------------------------ | BJT - model parameters (output-only) | |-----------------------------------------------------------+ | type NPN or PNP | | invearlyvoltf Inverse early voltage:forward | | invearlyvoltr Inverse early voltage:reverse | | invrollofff Inverse roll off - forward | ------------------------------------------------------------ | invrolloffr Inverse roll off - reverse | | collectorconduct Collector conductance | | emitterconduct Emitter conductance | | transtimevbcfact Transit time VBC factor | | excessphasefactor Excess phase fact. | ------------------------------------------------------------

B.4.BSIM1:BerkeleyShortChannelIGFETModel------------------------------------------------------------ | BSIM1 - instance parameters (input-only) | |-----------------------------------------------------------+ | ic Vector of DS,GS,BS initial voltages | ------------------------------------------------------------

------------------------------------------------------------ | BSIM1 - instance parameters (input-output) | |-----------------------------------------------------------+ | l Length | | w Width | | ad Drain area | | as Source area | ------------------------------------------------------------ | pd Drain perimeter | | ps Source perimeter | | nrd Number of squares in drain | | nrs Number of squares in source | |-----------------------------------------------------------+ | off Device is initially off | | vds Initial D-S voltage | | vgs Initial G-S voltage | | vbs Initial B-S voltage | ------------------------------------------------------------

------------------------------------------------------------ | BSIM1 - model parameters (input-only) | |-----------------------------------------------------------+ | nmos Flag to indicate NMOS | | pmos Flag to indicate PMOS | ------------------------------------------------------------

------------------------------------------------------------ | BSIM1 - model parameters (input-output) | |-----------------------------------------------------------+ | vfb Flat band voltage | lvfb Length dependence of vfb | wvfb Width dependence of vfb | | phi Strong inversion surface potential | ------------------------------------------------------------ | lphi Length dependence of phi | | wphi Width dependence of phi | | k1 Bulk effect coefficient 1 | | lk1 Length dependence of k1 | |-----------------------------------------------------------+ | wk1 Width dependence of k1 | | k2 Bulk effect coefficient 2 | | lk2 Length dependence of k2 | | wk2 Width dependence of k2 | ------------------------------------------------------------ | eta VDS dependence of threshold voltage | | leta Length dependence of eta | | weta Width dependence of eta | | x2e VBS dependence of eta | | lx2e Length dependence of x2e | |continued| ------------------------------------------------------------

--------------------------------------------------------------------- | BSIM1 - model input-output parameters -continued| |--------------------------------------------------------------------+ |wx2e Width dependence of x2e | |x3e VDS dependence of eta | |lx3e Length dependence of x3e | |wx3e Width dependence of x3e | --------------------------------------------------------------------- |dl Channel length reduction in um | |dw Channel width reduction in um | |muz Zero field mobility at VDS=0 VGS=VTH | |x2mz VBS dependence of muz | |--------------------------------------------------------------------+ |lx2mz Length dependence of x2mz | |wx2mz Width dependence of x2mz | mus Mobility at VDS=VDD VGS=VTH, channel length modulation |lmus Length dependence of mus | --------------------------------------------------------------------- |wmus Width dependence of mus | |x2ms VBS dependence of mus | |lx2ms Length dependence of x2ms | |wx2ms Width dependence of x2ms | |--------------------------------------------------------------------+ |x3ms VDS dependence of mus | |lx3ms Length dependence of x3ms | |wx3ms Width dependence of x3ms | |u0 VGS dependence of mobility | --------------------------------------------------------------------- |lu0 Length dependence of u0 | |wu0 Width dependence of u0 | |x2u0 VBS dependence of u0 | |lx2u0 Length dependence of x2u0 | |--------------------------------------------------------------------+ |wx2u0 Width dependence of x2u0 | |u1 VDS depence of mobility, velocity saturation | |lu1 Length dependence of u1 | |wu1 Width dependence of u1 | --------------------------------------------------------------------- |x2u1 VBS depence of u1 | |lx2u1 Length depence of x2u1 | |wx2u1 Width depence of x2u1 | |x3u1 VDS depence of u1 | |--------------------------------------------------------------------+ |lx3u1 Length dependence of x3u1 | |wx3u1 Width depence of x3u1 | |n0 Subthreshold slope | ln0 Length dependence of n0 --------------------------------------------------------------------- |wn0 Width dependence of n0 | |nb VBS dependence of subthreshold slope | |lnb Length dependence of nb | |wnb Width dependence of nb | |--------------------------------------------------------------------+ |nd VDS dependence of subthreshold slope | |lnd Length dependence of nd | |wnd Width dependence of nd | |continued| ---------------------------------------------------------------------

--------------------------------------------------------------------------- | BSIM1 - model input-output parameters -continued| |--------------------------------------------------------------------------+ |tox Gate oxide thickness in um | |temp Temperature in degree Celcius | |vdd Supply voltage to specify mus | |cgso Gate source overlap capacitance per unit channel width(m) | --------------------------------------------------------------------------- |cgdo Gate drain overlap capacitance per unit channel width(m) | |cgbo Gate bulk overlap capacitance per unit channel length(m) | |xpart Flag for channel charge partitioning | |rsh Source drain diffusion sheet resistance in ohm per square | |--------------------------------------------------------------------------+ |js Source drain junction saturation current per unit area | |pb Source drain junction built in potential | mj Source drain bottom junction capacitance grading coefficient |pbsw Source drain side junction capacitance built in potential | --------------------------------------------------------------------------- |mjsw Source drain side junction capacitance grading coefficient | |cj Source drain bottom junction capacitance per unit area | |cjsw Source drain side junction capacitance per unit area | |wdf Default width of source drain diffusion in um | |dell Length reduction of source drain diffusion | ---------------------------------------------------------------------------

B.5.BSIM2:BerkeleyShortChannelIGFETModel------------------------------------------------------------ | BSIM2 - instance parameters (input-only) | |-----------------------------------------------------------+ | ic Vector of DS,GS,BS initial voltages | ------------------------------------------------------------

------------------------------------------------------------ | BSIM2 - instance parameters (input-output) | |-----------------------------------------------------------+ | l Length | | w Width | | ad Drain area | | as Source area | ------------------------------------------------------------ | pd Drain perimeter | | ps Source perimeter | | nrd Number of squares in drain | | nrs Number of squares in source | |-----------------------------------------------------------+ | off Device is initially off | | vds Initial D-S voltage | | vgs Initial G-S voltage | | vbs Initial B-S voltage | ------------------------------------------------------------

------------------------------------------------------------ | BSIM2 - model parameters (input-only) | |-----------------------------------------------------------+ | nmos Flag to indicate NMOS | | pmos Flag to indicate PMOS | ------------------------------------------------------------

------------------------------------------------------------ | BSIM2 - model parameters (input-output) | |-----------------------------------------------------------+ |vfb Flat band voltage | |lvfb Length dependence of vfb | |wvfb Width dependence of vfb | |phi Strong inversion surface potential | ------------------------------------------------------------ |lphi Length dependence of phi | |wphi Width dependence of phi | |k1 Bulk effect coefficient 1 | |lk1 Length dependence of k1 | |-----------------------------------------------------------+ |wk1 Width dependence of k1 | |k2 Bulk effect coefficient 2 | |lk2 Length dependence of k2 | |wk2 Width dependence of k2 | ------------------------------------------------------------ |eta0 VDS dependence of threshold voltage at VDD=0 |leta0 Length dependence of eta0 | |weta0 Width dependence of eta0 | |etab VBS dependence of eta | |-----------------------------------------------------------+ |letab Length dependence of etab | |wetab Width dependence of etab | |dl Channel length reduction in um | |dw Channel width reduction in um | ------------------------------------------------------------ |mu0 Low-field mobility, at VDS=0 VGS=VTH | |mu0b VBS dependence of low-field mobility | |lmu0b Length dependence of mu0b | |wmu0b Width dependence of mu0b | |-----------------------------------------------------------+ |mus0 Mobility at VDS=VDD VGS=VTH | |lmus0 Length dependence of mus0 | |wmus0 Width dependence of mus | |musb VBS dependence of mus | ------------------------------------------------------------ |lmusb Length dependence of musb | |wmusb Width dependence of musb | |mu20 VDS dependence of mu in tanh term | |lmu20 Length dependence of mu20 | |-----------------------------------------------------------+ |wmu20 Width dependence of mu20 | |mu2b VBS dependence of mu2 | |lmu2b Length dependence of mu2b | |wmu2b Width dependence of mu2b | ------------------------------------------------------------ |mu2g VGS dependence of mu2 | |continued| ------------------------------------------------------------

------------------------------------------------------------ | BSIM2 - model input-output parameters -continued|-----------------------------------------------------------+ | lmu2g Length dependence of mu2g | | wmu2g Width dependence of mu2g | | mu30 VDS dependence of mu in linear term | | lmu30 Length dependence of mu30 | ------------------------------------------------------------ | wmu30 Width dependence of mu30 | | mu3b VBS dependence of mu3 | | lmu3b Length dependence of mu3b | | wmu3b Width dependence of mu3b | |-----------------------------------------------------------+ | mu3g VGS dependence of mu3 | | lmu3g Length dependence of mu3g | | wmu3g Width dependence of mu3g | | mu40 VDS dependence of mu in linear term | ------------------------------------------------------------ | lmu40 Length dependence of mu40 | | wmu40 Width dependence of mu40 | | mu4b VBS dependence of mu4 | | lmu4b Length dependence of mu4b | |-----------------------------------------------------------+ | wmu4b Width dependence of mu4b | | mu4g VGS dependence of mu4 | | lmu4g Length dependence of mu4g | | wmu4g Width dependence of mu4g | ------------------------------------------------------------ | ua0 Linear VGS dependence of mobility | | lua0 Length dependence of ua0 | | wua0 Width dependence of ua0 | | uab VBS dependence of ua | |-----------------------------------------------------------+ | luab Length dependence of uab | | wuab Width dependence of uab | | ub0 Quadratic VGS dependence of mobility | | lub0 Length dependence of ub0 | ------------------------------------------------------------ | wub0 Width dependence of ub0 | | ubb VBS dependence of ub | | lubb Length dependence of ubb | | wubb Width dependence of ubb | |-----------------------------------------------------------+ | u10 VDS depence of mobility | | lu10 Length dependence of u10 | wu10 Width dependence of u10 | u1b VBS depence of u1 | ------------------------------------------------------------ | lu1b Length depence of u1b | | wu1b Width depence of u1b | | u1d VDS depence of u1 | | lu1d Length depence of u1d | |-----------------------------------------------------------+ | wu1d Width depence of u1d | | n0 Subthreshold slope at VDS=0 VBS=0 | | ln0 Length dependence of n0 | |continued| ------------------------------------------------------------

------------------------------------------------------------------------ | BSIM2 - model input-output parameters -continued| |-----------------------------------------------------------------------+ |wn0 Width dependence of n0 | |nb VBS dependence of n | |lnb Length dependence of nb | |wnb Width dependence of nb | ------------------------------------------------------------------------ |nd VDS dependence of n | |lnd Length dependence of nd | |wnd Width dependence of nd | |vof0 Threshold voltage offset AT VDS=0 VBS=0 | |-----------------------------------------------------------------------+ |lvof0 Length dependence of vof0 | |wvof0 Width dependence of vof0 | |vofb VBS dependence of vof | |lvofb Length dependence of vofb | ------------------------------------------------------------------------ |wvofb Width dependence of vofb | |vofd VDS dependence of vof | |lvofd Length dependence of vofd | |wvofd Width dependence of vofd | |-----------------------------------------------------------------------+ |ai0 Pre-factor of hot-electron effect. | |lai0 Length dependence of ai0 | |wai0 Width dependence of ai0 | |aib VBS dependence of ai | ------------------------------------------------------------------------ |laib Length dependence of aib | |waib Width dependence of aib | |bi0 Exponential factor of hot-electron effect. | |lbi0 Length dependence of bi0 | |-----------------------------------------------------------------------+ |wbi0 Width dependence of bi0 | |bib VBS dependence of bi | |lbib Length dependence of bib | |wbib Width dependence of bib | ------------------------------------------------------------------------ |vghigh Upper bound of the cubic spline function. | |lvghigh Length dependence of vghigh | |wvghigh Width dependence of vghigh | |vglow Lower bound of the cubic spline function. | |-----------------------------------------------------------------------+ |lvglow Length dependence of vglow | |wvglow Width dependence of vglow | |tox Gate oxide thickness in um | |temp Temperature in degree Celcius | ------------------------------------------------------------------------ |vdd Maximum Vds | |vgg Maximum Vgs | |vbb Maximum Vbs | |cgso Gate source overlap capacitance per unit channel width(m) |-----------------------------------------------------------------------+ |cgdo Gate drain overlap capacitance per unit channel width(m)| |cgbo Gate bulk overlap capacitance per unit channel length(m)| |xpart Flag for channel charge partitioning | |continued| ------------------------------------------------------------------------

--------------------------------------------------------------------------- | BSIM2 - model input-output parameters -continued| |--------------------------------------------------------------------------+ |rsh Source drain diffusion sheet resistance in ohm per square | |js Source drain junction saturation current per unit area | |pb Source drain junction built in potential | mj Source drain bottom junction capacitance grading coefficient | | --------------------------------------------------------------------------- |pbsw Source drain side junction capacitance built in potential | |mjsw Source drain side junction capacitance grading coefficient | |cj Source drain bottom junction capacitance per unit area | |cjsw Source drain side junction capacitance per unit area | |wdf Default width of source drain diffusion in um | |dell Length reduction of source drain diffusion | ---------------------------------------------------------------------------

B.6.Capacitor:Fixedcapacitor------------------------------------------------------------ | Capacitor - instance parameters (input-output) | |-----------------------------------------------------------+ | capacitance Device capacitance | | ic Initial capacitor voltage | | w Device width | | l Device length | ------------------------------------------------------------

------------------------------------------------------------ | Capacitor - instance parameters (output-only) | |-----------------------------------------------------------+ | i Device current | | p Instantaneous device power | ------------------------------------------------------------

------------------------------------------------------------ | Capacitor - model parameters (input-only) | |-----------------------------------------------------------+ | c Capacitor model | ------------------------------------------------------------

------------------------------------------------------------ | Capacitor - model parameters (input-output) | |-----------------------------------------------------------+ | cj Bottom Capacitance per area | | cjsw Sidewall capacitance per meter | | defw Default width | | narrow width correction factor | ------------------------------------------------------------

B.7.CCCS:Currentcontrolledcurrentsource------------------------------------------------------------ | CCCS - instance parameters (input-output) | |-----------------------------------------------------------+ | gain Gain of source | | control Name of controlling source | ------------------------------------------------------------

------------------------------------------------------------ | CCCS - instance parameters (output-only) | |-----------------------------------------------------------+ | neg_node Negative node of source | | pos_node Positive node of source | | i CCCS output current | | v CCCS voltage at output | | p CCCS power | ------------------------------------------------------------

B.8.CCVS:Linearcurrentcontrolledcurrentsource------------------------------------------------------------ | CCVS - instance parameters (input-output) | |-----------------------------------------------------------+ | gain Transresistance (gain) | | control Controlling voltage source | ------------------------------------------------------------

------------------------------------------------------------ | CCVS - instance parameters (output-only) | |-----------------------------------------------------------+ | pos_node Positive node of source | | neg_node Negative node of source | | i CCVS output current | | v CCVS output voltage | | p CCVS power | ------------------------------------------------------------

B.9.CSwitch:Currentcontrolledidealswitch------------------------------------------------------------ | CSwitch - instance parameters (input-only) | |-----------------------------------------------------------+ | on Initially closed | | off Initially open | ------------------------------------------------------------

------------------------------------------------------------ | CSwitch - instance parameters (input-output) | |-----------------------------------------------------------+ | control Name of controlling source | ------------------------------------------------------------

------------------------------------------------------------ | CSwitch - instance parameters (output-only) | |-----------------------------------------------------------+ | pos_node Positive node of switch | | neg_node Negative node of switch | | i Switch current | | p Instantaneous power | ------------------------------------------------------------

------------------------------------------------------------ | CSwitch - model parameters (input-output) | |-----------------------------------------------------------+ | csw Current controlled switch model | | it Threshold current | | ih Hysterisis current | | ron Closed resistance | | roff Open resistance | ------------------------------------------------------------

------------------------------------------------------------ | CSwitch - model parameters (output-only) | |-----------------------------------------------------------+ | gon Closed conductance | | goff Open conductance | ------------------------------------------------------------

B.10.Diode:JunctionDiodemodel------------------------------------------------------------ | Diode - instance parameters (input-output) | |-----------------------------------------------------------+ | off Initially off | | temp Instance temperature | | ic Initial device voltage | | area Area factor | ------------------------------------------------------------

------------------------------------------------------------ | Diode - instance parameters (output-only) | |-----------------------------------------------------------+ | vd Diode voltage | | id Diode current | | c Diode current | | gd Diode conductance | ------------------------------------------------------------ | cd Diode capacitance | | charge Diode capacitor charge | | capcur Diode capacitor current | | p Diode power | ------------------------------------------------------------

------------------------------------------------------------ | Diode - model parameters (input-only) | |-----------------------------------------------------------+ | d Diode model | ------------------------------------------------------------

------------------------------------------------------------ | Diode - model parameters (input-output) | |-----------------------------------------------------------+ | is Saturation current | | tnom Parameter measurement temperature | | rs Ohmic resistance | | n Emission Coefficient | ------------------------------------------------------------ | tt Transit Time | | cjo Junction capacitance | | cj0 (null) | | vj Junction potential | |-----------------------------------------------------------+ | m Grading coefficient | | eg Activation energy | | xti Saturation current temperature exp. | | kf flicker noise coefficient | ------------------------------------------------------------ | af flicker noise exponent | | fc Forward bias junction fit parameter | | bv Reverse breakdown voltage | | ibv Current at reverse breakdown voltage | ------------------------------------------------------------

------------------------------------------------------------ | Diode - model parameters (output-only) | |-----------------------------------------------------------+ | cond Ohmic conductance | ------------------------------------------------------------

B.11.Inductor:Inductors------------------------------------------------------------ | Inductor - instance parameters (input-output) | |-----------------------------------------------------------+ | inductance Inductance of inductor | | ic Initial current through inductor | ------------------------------------------------------------

------------------------------------------------------------- | Inductor - instance parameters (output-only) | |------------------------------------------------------------+ |flux Flux through inductor | |v Terminal voltage of inductor | |volt | |i Current through the inductor | |current | p instantaneous power dissipated by the inductor | | -------------------------------------------------------------

B.12.mutual:Mutualinductors------------------------------------------------------------ | mutual - instance parameters (input-output) | |-----------------------------------------------------------+ | k Mutual inductance | | coefficient (null) | | inductor1 First coupled inductor | | inductor2 Second coupled inductor | ------------------------------------------------------------

B.13.Isource:Independentcurrentsource------------------------------------------------------------ | Isource - instance parameters (input-only) | |-----------------------------------------------------------+ | pulse Pulse description | | sine Sinusoidal source description | | sin Sinusoidal source description | | exp Exponential source description | ------------------------------------------------------------ | pwl Piecewise linear description | | sffm single freq. FM description | | ac AC magnitude,phase vector | | c Current through current source | | distof1 f1 input for distortion | | distof2 f2 input for distortion | ------------------------------------------------------------

------------------------------------------------------------ | Isource - instance parameters (input-output) | |-----------------------------------------------------------+ | dc DC value of source | | acmag AC magnitude | | acphase AC phase | ------------------------------------------------------------

------------------------------------------------------------ | Isource - instance parameters (output-only) | |-----------------------------------------------------------+ | neg_node Negative node of source | | pos_node Positive node of source | acreal AC real part | acimag AC imaginary part | ------------------------------------------------------------ | function Function of the source | | order Order of the source function | | coeffs Coefficients of the source | | v Voltage across the supply | | p Power supplied by the source | ------------------------------------------------------------

B.14.JFET:JunctionFieldeffecttransistor------------------------------------------------------------ | JFET - instance parameters (input-output) | |-----------------------------------------------------------+ | off Device initially off | | ic Initial VDS,VGS vector | | area Area factor | | ic-vds Initial D-S voltage | | ic-vgs Initial G-S volrage | | temp Instance temperature | ------------------------------------------------------------

--------------------------------------------------------------- | JFET - instance parameters (output-only) | |--------------------------------------------------------------+ |drain-node Number of drain node | |gate-node Number of gate node | |source-node Number of source node | |drain-prime-node Internal drain node | --------------------------------------------------------------- |source-prime-nodeInternal source node | |vgs Voltage G-S | |vgd Voltage G-D | |ig Current at gate node | |--------------------------------------------------------------+ |id Current at drain node | |is Source current | |igd Current G-D | |gm Transconductance | --------------------------------------------------------------- |gds Conductance D-S | |ggs Conductance G-S | |ggd Conductance G-D | |qgs Charge storage G-S junction | |--------------------------------------------------------------+ |qgd Charge storage G-D junction | cqgs Capacitance due to charge storage G-S junction | | cqgd Capacitance due to charge storage G-D junction |p Power dissipated by the JFET | ---------------------------------------------------------------

------------------------------------------------------------ | JFET - model parameters (input-output) | |-----------------------------------------------------------+ | njf N type JFET model | | pjf P type JFET model | | vt0 Threshold voltage | | vto (null) | ------------------------------------------------------------ | beta Transconductance parameter | | lambda Channel length modulation param. | | rd Drain ohmic resistance | | rs Source ohmic resistance | | cgs G-S junction capactance | |continued| ------------------------------------------------------------

------------------------------------------------------------ | JFET - model input-output parameters -continued|-----------------------------------------------------------+ | cgd G-D junction cap | | pb Gate junction potential | | is Gate junction saturation current | | fc Forward bias junction fit parm. | ------------------------------------------------------------ | b Doping tail parameter | | tnom parameter measurement temperature | | kf Flicker Noise Coefficient | | af Flicker Noise Exponent | ------------------------------------------------------------

------------------------------------------------------------ | JFET - model parameters (output-only) | |-----------------------------------------------------------+ | type N-type or P-type JFET model | | gd Drain conductance | | gs Source conductance | ------------------------------------------------------------

B.15.LTRA:Lossytransmissionline------------------------------------------------------------ | LTRA - instance parameters (input-only) | |-----------------------------------------------------------+ | ic Initial condition vector:v1,i1,v2,i2 | ------------------------------------------------------------

------------------------------------------------------------ | LTRA - instance parameters (input-output) | |-----------------------------------------------------------+ | v1 Initial voltage at end 1 | | v2 Initial voltage at end 2 | | i1 Initial current at end 1 | | i2 Initial current at end 2 | ------------------------------------------------------------

------------------------------------------------------------ | LTRA - instance parameters (output-only) | |-----------------------------------------------------------+ | pos_node1 Positive node of end 1 of t-line | | neg_node1 Negative node of end 1 of t.line | | pos_node2 Positive node of end 2 of t-line | | neg_node2 Negative node of end 2 of t-line | ------------------------------------------------------------

------------------------------------------------------------ | LTRA - model parameters (input-output) | |-----------------------------------------------------------+ |ltra LTRA model | |r Resistance per metre | |l Inductance per metre | |g (null) | ------------------------------------------------------------ |c Capacitance per metre | |len length of line | |nocontrol No timestep control | |steplimit always limit timestep to 0.8*(delay of line) |continued| ------------------------------------------------------------

----------------------------------------------------------------------------------- | LTRA - model input-output parameters -continued| |----------------------------------------------------------------------------------+ |nosteplimit don't always limit timestep to 0.8*(delay of line) | |lininterp use linear interpolation | |quadinterp use quadratic interpolation | |mixedinterp use linear interpolation if quadratic results look unacceptable | ----------------------------------------------------------------------------------- |truncnr use N-R iterations for step calculation in LTRAtrunc | |truncdontcut don't limit timestep to keep impulse response calculation errors low |compactrel special reltol for straight line checking | |compactabs special abstol for straight line checking | -----------------------------------------------------------------------------------

------------------------------------------------------------ | LTRA - model parameters (output-only) | |-----------------------------------------------------------+ | rel Rel. rate of change of deriv. for bkpt | | abs Abs. rate of change of deriv. for bkpt | ------------------------------------------------------------

B.16.MES:GaAsMESFETmodel------------------------------------------------------------ | MES - instance parameters (input-output) | |-----------------------------------------------------------+ | area Area factor | | icvds Initial D-S voltage | | icvgs Initial G-S voltage | ------------------------------------------------------------

------------------------------------------------------------ | MES - instance parameters (output-only) | |-----------------------------------------------------------+ |off Device initially off | |dnode Number of drain node | |gnode Number of gate node | |snode Number of source node | ------------------------------------------------------------ |dprimenode Number of internal drain node | |sprimenode Number of internal source node | |vgs Gate-Source voltage | |vgd Gate-Drain voltage | |-----------------------------------------------------------+ |cg Gate capacitance | |cd Drain capacitance | |cgd Gate-Drain capacitance | |gm Transconductance | ------------------------------------------------------------ |gds Drain-Source conductance | |ggs Gate-Source conductance | |ggd Gate-Drain conductance | |cqgs Capacitance due to gate-source charge storage |-----------------------------------------------------------+ |cqgd Capacitance due to gate-drain charge storage| |qgs Gate-Source charge storage | |qgd Gate-Drain charge storage | |is Source current | |continued| ------------------------------------------------------------

------------------------------------------------------------ | MES - instance output-only parameters -continued|-----------------------------------------------------------+ | p Power dissipated by the mesfet | ------------------------------------------------------------ ------------------------------------------------------------ | MES - model parameters (input-only) | |-----------------------------------------------------------+ | nmf N type MESfet model | | pmf P type MESfet model | ------------------------------------------------------------

------------------------------------------------------------ | MES - model parameters (input-output) | |-----------------------------------------------------------+ | vt0 Pinch-off voltage | | vto (null) | | alpha Saturation voltage parameter | | beta Transconductance parameter | ------------------------------------------------------------ | lambda Channel length modulation parm. | | b Doping tail extending parameter | | rd Drain ohmic resistance | | rs Source ohmic resistance | |-----------------------------------------------------------+ | cgs G-S junction capacitance | | cgd G-D junction capacitance | | pb Gate junction potential | | is Junction saturation current | ------------------------------------------------------------ | fc Forward bias junction fit parm. | | kf Flicker noise coefficient | | af Flicker noise exponent | ------------------------------------------------------------

------------------------------------------------------------ | MES - model parameters (output-only) | |-----------------------------------------------------------+ | type N-type or P-type MESfet model | | gd Drain conductance | | gs Source conductance | | depl_cap Depletion capacitance | | vcrit Critical voltage | ------------------------------------------------------------

B.17.Mos1:Level1MOSfetmodelwithMeyercapacitancemodel------------------------------------------------------------ | Mos1 - instance parameters (input-only) | |-----------------------------------------------------------+ | off Device initially off | | ic Vector of D-S, G-S, B-S voltages | ------------------------------------------------------------

------------------------------------------------------------ | Mos1 - instance parameters (input-output) | |-----------------------------------------------------------+ | l Length | | w Width | | ad Drain area | | as Source area | ------------------------------------------------------------ | pd Drain perimeter | | ps Source perimeter | | nrd Drain squares | | nrs Source squares | |-----------------------------------------------------------+ | icvds Initial D-S voltage | | icvgs Initial G-S voltage | | icvbs Initial B-S voltage | | temp Instance temperature | ------------------------------------------------------------

------------------------------------------------------------ | Mos1 - instance parameters (output-only) | |-----------------------------------------------------------+ | id Drain current | | is Source current | | ig Gate current | | ib Bulk current | ------------------------------------------------------------ | ibd B-D junction current | | ibs B-S junction current | | vgs Gate-Source voltage | | vds Drain-Source voltage | |-----------------------------------------------------------+ | vbs Bulk-Source voltage | | vbd Bulk-Drain voltage | | dnode Number of the drain node | | gnode Number of the gate node | ------------------------------------------------------------ | snode Number of the source node | | bnode Number of the node | | dnodeprime Number of int. drain node | | snodeprime Number of int. source node | |-----------------------------------------------------------+ | von | | vdsat Saturation drain voltage | | sourcevcrit Critical source voltage | | drainvcrit Critical drain voltage | | rs Source resistance | |continued| ------------------------------------------------------------

-------------------------------------------------------------- | Mos1 - instance output-only parameters -continued|-------------------------------------------------------------+ |sourceconductanceConductance of source | |rd Drain conductance | |drainconductance Conductance of drain | |gm Transconductance | -------------------------------------------------------------- |gds Drain-Source conductance | |gmb Bulk-Source transconductance | |gmbs | |gbd Bulk-Drain conductance | |-------------------------------------------------------------+ |gbs Bulk-Source conductance | |cbd Bulk-Drain capacitance | |cbs Bulk-Source capacitance | |cgs Gate-Source capacitance | -------------------------------------------------------------- |cgd Gate-Drain capacitance | |cgb Gate-Bulk capacitance | |cqgs Capacitance due to gate-source charge storage |cqgd Capacitance due to gate-drain charge storage| |-------------------------------------------------------------+ |cqgb Capacitance due to gate-bulk charge storage | |cqbd Capacitance due to bulk-drain charge storage| cqbs Capacitance due to bulk-source charge storage |cbd0 Zero-Bias B-D junction capacitance | -------------------------------------------------------------- |cbdsw0 | |cbs0 Zero-Bias B-S junction capacitance | |cbssw0 | |qgs Gate-Source charge storage | |-------------------------------------------------------------+ |qgd Gate-Drain charge storage | |qgb Gate-Bulk charge storage | |qbd Bulk-Drain charge storage | |qbs Bulk-Source charge storage | |p Instaneous power | --------------------------------------------------------------

------------------------------------------------------------ | Mos1 - model parameters (input-only) | |-----------------------------------------------------------+ | nmos N type MOSfet model | | pmos P type MOSfet model | ------------------------------------------------------------

------------------------------------------------------------ | Mos1 - model parameters (input-output) | |-----------------------------------------------------------+ | vto Threshold voltage | | vt0 (null) | | kp Transconductance parameter | | gamma Bulk threshold parameter | ------------------------------------------------------------ | phi Surface potential | | lambda Channel length modulation | | rd Drain ohmic resistance | |continued| ------------------------------------------------------------

------------------------------------------------------------ | Mos1 - model input-output parameters -continued|-----------------------------------------------------------+ | rs Source ohmic resistance | | cbd B-D junction capacitance | | cbs B-S junction capacitance | | is Bulk junction sat. current | ------------------------------------------------------------ | pb Bulk junction potential | | cgso Gate-source overlap cap. | | cgdo Gate-drain overlap cap. | | cgbo Gate-bulk overlap cap. | |-----------------------------------------------------------+ | rsh Sheet resistance | | cj Bottom junction cap per area | | mj Bottom grading coefficient | | cjsw Side junction cap per area | ------------------------------------------------------------ | mjsw Side grading coefficient | | js Bulk jct. sat. current density | | tox Oxide thickness | | ld Lateral diffusion | |-----------------------------------------------------------+ | u0 Surface mobility | | uo (null) | | fc Forward bias jct. fit parm. | | nsub Substrate doping | ------------------------------------------------------------ | tpg Gate type | | nss Surface state density | | tnom Parameter measurement temperature | | kf Flicker noise coefficient | | af Flicker noise exponent | ------------------------------------------------------------

------------------------------------------------------------ | Mos1 - model parameters (output-only) | |-----------------------------------------------------------+ | type N-channel or P-channel MOS | ------------------------------------------------------------

B.18.Mos2:Level2MOSfetmodelwithMeyercapacitancemodel------------------------------------------------------------ | Mos2 - instance parameters (input-only) | |-----------------------------------------------------------+ | off Device initially off | | ic Vector of D-S, G-S, B-S voltages | ------------------------------------------------------------

------------------------------------------------------------ | Mos2 - instance parameters (input-output) | |-----------------------------------------------------------+ | l Length | | w Width | | ad Drain area | | as Source area | ------------------------------------------------------------ | pd Drain perimeter | | ps Source perimeter | | nrd Drain squares | | nrs Source squares | |-----------------------------------------------------------+ | icvds Initial D-S voltage | | icvgs Initial G-S voltage | | icvbs Initial B-S voltage | | temp Instance operating temperature | ------------------------------------------------------------

------------------------------------------------------------ | Mos2 - instance parameters (output-only) | |-----------------------------------------------------------+ | id Drain current | | cd | | ibd B-D junction current | | ibs B-S junction current | ------------------------------------------------------------ | is Source current | | ig Gate current | | ib Bulk current | | vgs Gate-Source voltage | |-----------------------------------------------------------+ | vds Drain-Source voltage | | vbs Bulk-Source voltage | | vbd Bulk-Drain voltage | | dnode Number of drain node | ------------------------------------------------------------ | gnode Number of gate node | | snode Number of source node | | bnode Number of bulk node | | dnodeprime Number of internal drain node | |-----------------------------------------------------------+ | snodeprime Number of internal source node | | von | | vdsat Saturation drain voltage | | sourcevcrit Critical source voltage | | drainvcrit Critical drain voltage | |continued| ------------------------------------------------------------

-------------------------------------------------------------- | Mos2 - instance output-only parameters -continued|-------------------------------------------------------------+ |rs Source resistance | |sourceconductanceSource conductance | |rd Drain resistance | |drainconductance Drain conductance | -------------------------------------------------------------- |gm Transconductance | |gds Drain-Source conductance | |gmb Bulk-Source transconductance | |gmbs | |-------------------------------------------------------------+ |gbd Bulk-Drain conductance | |gbs Bulk-Source conductance | |cbd Bulk-Drain capacitance | |cbs Bulk-Source capacitance | -------------------------------------------------------------- |cgs Gate-Source capacitance | |cgd Gate-Drain capacitance | |cgb Gate-Bulk capacitance | |cbd0 Zero-Bias B-D junction capacitance | |-------------------------------------------------------------+ |cbdsw0 | |cbs0 Zero-Bias B-S junction capacitance | |cbssw0 | cqgs Capacitance due to gate-source charge storage | | -------------------------------------------------------------- |cqgd Capacitance due to gate-drain charge storage| |cqgb Capacitance due to gate-bulk charge storage | |cqbd Capacitance due to bulk-drain charge storage| |cqbs Capacitance due to bulk-source charge storage |-------------------------------------------------------------+ |qgs Gate-Source charge storage | |qgd Gate-Drain charge storage | |qgb Gate-Bulk charge storage | |qbd Bulk-Drain charge storage | |qbs Bulk-Source charge storage | |p Instantaneous power | --------------------------------------------------------------

------------------------------------------------------------ | Mos2 - model parameters (input-only) | |-----------------------------------------------------------+ | nmos N type MOSfet model | | pmos P type MOSfet model | ------------------------------------------------------------

------------------------------------------------------------ | Mos2 - model parameters (input-output) | |-----------------------------------------------------------+ | vto Threshold voltage | | vt0 (null) | | kp Transconductance parameter | | gamma Bulk threshold parameter | ------------------------------------------------------------ | phi Surface potential | | lambda Channel length modulation | | rd Drain ohmic resistance | | rs Source ohmic resistance | |-----------------------------------------------------------+ | cbd B-D junction capacitance | | cbs B-S junction capacitance | | is Bulk junction sat. current | | pb Bulk junction potential | ------------------------------------------------------------ | cgso Gate-source overlap cap. | | cgdo Gate-drain overlap cap. | | cgbo Gate-bulk overlap cap. | | rsh Sheet resistance | |-----------------------------------------------------------+ | cj Bottom junction cap per area | | mj Bottom grading coefficient | | cjsw Side junction cap per area | | mjsw Side grading coefficient | ------------------------------------------------------------ | js Bulk jct. sat. current density | | tox Oxide thickness | | ld Lateral diffusion | | u0 Surface mobility | |-----------------------------------------------------------+ | uo (null) | | fc Forward bias jct. fit parm. | | nsub Substrate doping | | tpg Gate type | ------------------------------------------------------------ | nss Surface state density | | delta Width effect on threshold | | uexp Crit. field exp for mob. deg. | | ucrit Crit. field for mob. degradation | |-----------------------------------------------------------+ | vmax Maximum carrier drift velocity | | xj Junction depth | | neff Total channel charge coeff. | | nfs Fast surface state density | ------------------------------------------------------------ | tnom Parameter measurement temperature | | kf Flicker noise coefficient | | af Flicker noise exponent | ------------------------------------------------------------

------------------------------------------------------------ | Mos2 - model parameters (output-only) | |-----------------------------------------------------------+ | type N-channel or P-channel MOS | ------------------------------------------------------------

B.19.Mos3:Level3MOSfetmodelwithMeyercapacitancemodel------------------------------------------------------------ | Mos3 - instance parameters (input-only) | |-----------------------------------------------------------+ | off Device initially off | ------------------------------------------------------------

------------------------------------------------------------ | Mos3 - instance parameters (input-output) | |-----------------------------------------------------------+ | l Length | | w Width | | ad Drain area | | as Source area | ------------------------------------------------------------ | pd Drain perimeter | | ps Source perimeter | | nrd Drain squares | | nrs Source squares | |-----------------------------------------------------------+ | icvds Initial D-S voltage | | icvgs Initial G-S voltage | | icvbs Initial B-S voltage | | ic Vector of D-S, G-S, B-S voltages | | temp Instance operating temperature | ------------------------------------------------------------

------------------------------------------------------------ | Mos3 - instance parameters (output-only) | |-----------------------------------------------------------+ | id Drain current | | cd Drain current | | ibd B-D junction current | | ibs B-S junction current | ------------------------------------------------------------ | is Source current | | ig Gate current | | ib Bulk current | | vgs Gate-Source voltage | |-----------------------------------------------------------+ | vds Drain-Source voltage | | vbs Bulk-Source voltage | | vbd Bulk-Drain voltage | | dnode Number of drain node | ------------------------------------------------------------ | gnode Number of gate node | | snode Number of source node | | bnode Number of bulk node | | dnodeprime Number of internal drain node | | snodeprime Number of internal source node | |continued| ------------------------------------------------------------

-------------------------------------------------------------- | Mos3 - instance output-only parameters -continued|-------------------------------------------------------------+ |von Turn-on voltage | |vdsat Saturation drain voltage | |sourcevcrit Critical source voltage | |drainvcrit Critical drain voltage | -------------------------------------------------------------- |rs Source resistance | |sourceconductanceSource conductance | |rd Drain resistance | |drainconductance Drain conductance | |-------------------------------------------------------------+ |gm Transconductance | |gds Drain-Source conductance | |gmb Bulk-Source transconductance | |gmbs Bulk-Source transconductance | -------------------------------------------------------------- |gbd Bulk-Drain conductance | |gbs Bulk-Source conductance | |cbd Bulk-Drain capacitance | |cbs Bulk-Source capacitance | |-------------------------------------------------------------+ |cgs Gate-Source capacitance | |cgd Gate-Drain capacitance | |cgb Gate-Bulk capacitance | cqgs Capacitance due to gate-source charge storage | | -------------------------------------------------------------- |cqgd Capacitance due to gate-drain charge storage| |cqgb Capacitance due to gate-bulk charge storage | |cqbd Capacitance due to bulk-drain charge storage| |cqbs Capacitance due to bulk-source charge storage |-------------------------------------------------------------+ |cbd0 Zero-Bias B-D junction capacitance | |cbdsw0 Zero-Bias B-D sidewall capacitance | |cbs0 Zero-Bias B-S junction capacitance | |cbssw0 Zero-Bias B-S sidewall capacitance | -------------------------------------------------------------- |qbs Bulk-Source charge storage | |qgs Gate-Source charge storage | |qgd Gate-Drain charge storage | |qgb Gate-Bulk charge storage | |qbd Bulk-Drain charge storage | |p Instantaneous power | --------------------------------------------------------------

------------------------------------------------------------ | Mos3 - model parameters (input-only) | |-----------------------------------------------------------+ | nmos N type MOSfet model | | pmos P type MOSfet model | ------------------------------------------------------------

------------------------------------------------------------ | Mos3 - model parameters (input-output) | |-----------------------------------------------------------+ | vto Threshold voltage | | vt0 (null) | | kp Transconductance parameter | | gamma Bulk threshold parameter | ------------------------------------------------------------ | phi Surface potential | | rd Drain ohmic resistance | | rs Source ohmic resistance | | cbd B-D junction capacitance | |-----------------------------------------------------------+ | cbs B-S junction capacitance | | is Bulk junction sat. current | | pb Bulk junction potential | | cgso Gate-source overlap cap. | ------------------------------------------------------------ | cgdo Gate-drain overlap cap. | | cgbo Gate-bulk overlap cap. | | rsh Sheet resistance | | cj Bottom junction cap per area | |-----------------------------------------------------------+ | mj Bottom grading coefficient | | cjsw Side junction cap per area | | mjsw Side grading coefficient | | js Bulk jct. sat. current density | ------------------------------------------------------------ | tox Oxide thickness | | ld Lateral diffusion | | u0 Surface mobility | | uo (null) | |-----------------------------------------------------------+ | fc Forward bias jct. fit parm. | | nsub Substrate doping | | tpg Gate type | | nss Surface state density | ------------------------------------------------------------ | vmax Maximum carrier drift velocity | | xj Junction depth | | nfs Fast surface state density | | xd Depletion layer width | |-----------------------------------------------------------+ | alpha Alpha | | eta Vds dependence of threshold voltage | | delta Width effect on threshold | | input_delta (null) | ------------------------------------------------------------ | theta Vgs dependence on mobility | | kappa Kappa | | tnom Parameter measurement temperature | | kf Flicker noise coefficient | | af Flicker noise exponent | ------------------------------------------------------------

------------------------------------------------------------ | Mos3 - model parameters (output-only) | |-----------------------------------------------------------+ | type N-channel or P-channel MOS | ------------------------------------------------------------

B.20.Mos6:Level6MOSfetmodelwithMeyercapacitancemodel------------------------------------------------------------ | Mos6 - instance parameters (input-only) | |-----------------------------------------------------------+ | off Device initially off | | ic Vector of D-S, G-S, B-S voltages | ------------------------------------------------------------

------------------------------------------------------------ | Mos6 - instance parameters (input-output) | |-----------------------------------------------------------+ | l Length | | w Width | | ad Drain area | | as Source area | ------------------------------------------------------------ | pd Drain perimeter | | ps Source perimeter | | nrd Drain squares | | nrs Source squares | |-----------------------------------------------------------+ | icvds Initial D-S voltage | | icvgs Initial G-S voltage | | icvbs Initial B-S voltage | | temp Instance temperature | ------------------------------------------------------------

------------------------------------------------------------ | Mos6 - instance parameters (output-only) | |-----------------------------------------------------------+ | id Drain current | | cd Drain current | | is Source current | | ig Gate current | ------------------------------------------------------------ | ib Bulk current | | ibs B-S junction capacitance | | ibd B-D junction capacitance | | vgs Gate-Source voltage | |-----------------------------------------------------------+ | vds Drain-Source voltage | | vbs Bulk-Source voltage | | vbd Bulk-Drain voltage | | dnode Number of the drain node | ------------------------------------------------------------ | gnode Number of the gate node | | snode Number of the source node | | bnode Number of the node | | dnodeprime Number of int. drain node | | snodeprime Number of int. source node | |continued| ------------------------------------------------------------

-------------------------------------------------------------- | Mos6 - instance output-only parameters -continued|-------------------------------------------------------------+ |rs Source resistance | |sourceconductanceSource conductance | |rd Drain resistance | |drainconductance Drain conductance | -------------------------------------------------------------- |von Turn-on voltage | |vdsat Saturation drain voltage | |sourcevcrit Critical source voltage | |drainvcrit Critical drain voltage | |-------------------------------------------------------------+ |gmbs Bulk-Source transconductance | |gm Transconductance | |gds Drain-Source conductance | |gbd Bulk-Drain conductance | -------------------------------------------------------------- |gbs Bulk-Source conductance | |cgs Gate-Source capacitance | |cgd Gate-Drain capacitance | |cgb Gate-Bulk capacitance | |-------------------------------------------------------------+ |cbd Bulk-Drain capacitance | |cbs Bulk-Source capacitance | |cbd0 Zero-Bias B-D junction capacitance | |cbdsw0 | -------------------------------------------------------------- |cbs0 Zero-Bias B-S junction capacitance | |cbssw0 | |cqgs Capacitance due to gate-source charge storage |cqgd Capacitance due to gate-drain charge storage| |-------------------------------------------------------------+ |cqgb Capacitance due to gate-bulk charge storage | |cqbd Capacitance due to bulk-drain charge storage| cqbs Capacitance due to bulk-source charge storage |qgs Gate-Source charge storage | -------------------------------------------------------------- |qgd Gate-Drain charge storage | |qgb Gate-Bulk charge storage | |qbd Bulk-Drain charge storage | |qbs Bulk-Source charge storage | |p Instaneous power | --------------------------------------------------------------

------------------------------------------------------------ | Mos6 - model parameters (input-only) | |-----------------------------------------------------------+ | nmos N type MOSfet model | | pmos P type MOSfet model | ------------------------------------------------------------

------------------------------------------------------------ | Mos6 - model parameters (input-output) | |-----------------------------------------------------------+ | vto Threshold voltage | | vt0 (null) | | kv Saturation voltage factor | | nv Saturation voltage coeff. | ------------------------------------------------------------ | kc Saturation current factor | | nc Saturation current coeff. | | nvth Threshold voltage coeff. | | ps Sat. current modification par. | |-----------------------------------------------------------+ | gamma Bulk threshold parameter | | gamma1 Bulk threshold parameter 1 | | sigma Static feedback effect par. | | phi Surface potential | ------------------------------------------------------------ | lambda Channel length modulation param. | | lambda0 Channel length modulation param. 0 | | lambda1 Channel length modulation param. 1 | | rd Drain ohmic resistance | |-----------------------------------------------------------+ | rs Source ohmic resistance | | cbd B-D junction capacitance | | cbs B-S junction capacitance | | is Bulk junction sat. current | ------------------------------------------------------------ | pb Bulk junction potential | | cgso Gate-source overlap cap. | | cgdo Gate-drain overlap cap. | | cgbo Gate-bulk overlap cap. | |-----------------------------------------------------------+ | rsh Sheet resistance | | cj Bottom junction cap per area | | mj Bottom grading coefficient | | cjsw Side junction cap per area | ------------------------------------------------------------ | mjsw Side grading coefficient | | js Bulk jct. sat. current density | | ld Lateral diffusion | | tox Oxide thickness | |-----------------------------------------------------------+ | u0 Surface mobility | | uo (null) | | fc Forward bias jct. fit parm. | | tpg Gate type | ------------------------------------------------------------ | nsub Substrate doping | | nss Surface state density | | tnom Parameter measurement temperature | ------------------------------------------------------------

------------------------------------------------------------ | Mos6 - model parameters (output-only) | |-----------------------------------------------------------+ | type N-channel or P-channel MOS | ------------------------------------------------------------

B.21.Resistor:Simplelinearresistor------------------------------------------------------------ | Resistor - instance parameters (input-output) | |-----------------------------------------------------------+ | resistance Resistance | | temp Instance operating temperature | | l Length | | w Width | ------------------------------------------------------------

------------------------------------------------------------ | Resistor - instance parameters (output-only) | |-----------------------------------------------------------+ | i Current | | p Power | ------------------------------------------------------------

------------------------------------------------------------ | Resistor - model parameters (input-only) | |-----------------------------------------------------------+ | r Device is a resistor model | ------------------------------------------------------------

------------------------------------------------------------ | Resistor - model parameters (input-output) | |-----------------------------------------------------------+ | rsh Sheet resistance | | narrow Narrowing of resistor | | tc1 First order temp. coefficient | | tc2 Second order temp. coefficient | | defw Default device width | | tnom Parameter measurement temperature | ------------------------------------------------------------

B.22.Switch:Idealvoltagecontrolledswitch------------------------------------------------------------ | Switch - instance parameters (input-only) | |-----------------------------------------------------------+ | on Switch initially closed | | off Switch initially open | ------------------------------------------------------------

------------------------------------------------------------ | Switch - instance parameters (input-output) | |-----------------------------------------------------------+ | pos_node Positive node of switch | | neg_node Negative node of switch | ------------------------------------------------------------

------------------------------------------------------------ | Switch - instance parameters (output-only) | |-----------------------------------------------------------+ | cont_p_node Positive contr. node of switch | | cont_n_node Positive contr. node of switch | | i Switch current | | p Switch power | ------------------------------------------------------------

------------------------------------------------------------ | Switch - model parameters (input-output) | |-----------------------------------------------------------+ | sw Switch model | | vt Threshold voltage | | vh Hysteresis voltage | | ron Resistance when closed | | roff Resistance when open | ------------------------------------------------------------

------------------------------------------------------------ | Switch - model parameters (output-only) | |-----------------------------------------------------------+ | gon Conductance when closed | | goff Conductance when open | ------------------------------------------------------------

B.23.Tranline:Losslesstransmissionline------------------------------------------------------------ | Tranline - instance parameters (input-only) | |-----------------------------------------------------------+ | ic Initial condition vector:v1,i1,v2,i2 | ------------------------------------------------------------

------------------------------------------------------------ | Tranline - instance parameters (input-output) | |-----------------------------------------------------------+ | z0 Characteristic impedance | | zo (null) | | f Frequency | | td Transmission delay | ------------------------------------------------------------ | nl Normalized length at frequency given | | v1 Initial voltage at end 1 | | v2 Initial voltage at end 2 | | i1 Initial current at end 1 | | i2 Initial current at end 2 | ------------------------------------------------------------

------------------------------------------------------------ | Tranline - instance parameters (output-only) | |-----------------------------------------------------------+ | rel Rel. rate of change of deriv. for bkpt | | abs Abs. rate of change of deriv. for bkpt | | pos_node1 Positive node of end 1 of t. line | | neg_node1 Negative node of end 1 of t. line | ------------------------------------------------------------ | pos_node2 Positive node of end 2 of t. line | | neg_node2 Negative node of end 2 of t. line | | delays Delayed values of excitation | ------------------------------------------------------------

B.24.VCCS:Voltagecontrolledcurrentsource------------------------------------------------------------ | VCCS - instance parameters (input-only) | |-----------------------------------------------------------+ | ic Initial condition of controlling source | ------------------------------------------------------------

------------------------------------------------------------ | VCCS - instance parameters (input-output) | |-----------------------------------------------------------+ | gain Transconductance of source (gain) | ------------------------------------------------------------

------------------------------------------------------------ | VCCS - instance parameters (output-only) | |-----------------------------------------------------------+ | pos_node Positive node of source | | neg_node Negative node of source | | cont_p_node Positive node of contr. source | | cont_n_node Negative node of contr. source | ------------------------------------------------------------ | i Output current | | v Voltage across output | | p Power | ------------------------------------------------------------

B.25.VCVS:Voltagecontrolledvoltagesource------------------------------------------------------------ | VCVS - instance parameters (input-only) | |-----------------------------------------------------------+ | ic Initial condition of controlling source | ------------------------------------------------------------

------------------------------------------------------------ | VCVS - instance parameters (input-output) | |-----------------------------------------------------------+ | gain Voltage gain | ------------------------------------------------------------

------------------------------------------------------------ | VCVS - instance parameters (output-only) | |-----------------------------------------------------------+ | pos_node Positive node of source | | neg_node Negative node of source | | cont_p_node Positive node of contr. source | cont_n_node Negative node of contr. source ------------------------------------------------------------ | i Output current | | v Output voltage | | p Power | ------------------------------------------------------------

B.26.Vsource:Independentvoltagesource------------------------------------------------------------ | Vsource - instance parameters (input-only) | |-----------------------------------------------------------+ | pulse Pulse description | | sine Sinusoidal source description | | sin Sinusoidal source description | | exp Exponential source description | ------------------------------------------------------------ | pwl Piecewise linear description | | sffm Single freq. FM descripton | | ac AC magnitude, phase vector | | distof1 f1 input for distortion | | distof2 f2 input for distortion | ------------------------------------------------------------

------------------------------------------------------------ | Vsource - instance parameters (input-output) | |-----------------------------------------------------------+ | dc D.C. source value | | acmag A.C. Magnitude | | acphase A.C. Phase | ------------------------------------------------------------

------------------------------------------------------------ | Vsource - instance parameters (output-only) | |-----------------------------------------------------------+ | pos_node Positive node of source | | neg_node Negative node of source | | function Function of the source | | order Order of the source function | ------------------------------------------------------------ | coeffs Coefficients for the function | | acreal AC real part | | acimag AC imaginary part | | i Voltage source current | | p Instantaneous power | ------------------------------------------------------------

- INTRODUCTION
- CIRCUIT DESCRIPTION
- CIRCUIT ELEMENTS AND MODELS
- ANALYSES AND OUTPUT CONTROL
- INTERACTIVE INTERPRETER
- EXPRESSIONS FUNCTIONS AND CONSTANTS
- COMMAND INTERPRETATION
- COMMANDS
- CONTROL STRUCTURES
- VARIABLES
- MISCELLANEOUS
- BUGS

- BIBLIOGRAPHY
- APPENDIX A
- APPENDIX B