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Device Models

Many devices reference models, which contain values for the numerous parameters describing the device, which would be cumbersome to include in each device reference. Device models are specified on a .model line. The model can be referenced by any number of devices of the corresponding type.

General Form:
.model modname type (pname1=pval1 pname2=pval2 ... )
Examples:
.model mod1 npn (bf=50 is=1e-13 vbf=50)
.model intercon ltra (r=0.2 l=9.13nh c=3.65pf len=5 rel=.002 compactrel=1.0E-4)

The .model line specifies a set of model parameters that will be used by one or more devices. The modname is the model name, which is case insensitive in matching references, and type is one of the following types:

c Capacitor model
r Resistor model
sw Voltage-controlled switch model
csw Current-controlled switch model
tra General transmission line model
ltra Lossy transmission line model
urc Uniform RC line model
d Diode model
npn NPN BJT model
pnp PNP BJT model
njf N-channel JFET model
pjf P-channel JFET model
nmf N-channel MESFET model
pmf P-channel MESFET model
nmos N-channel MOSFET model
pmos P-channel MOSFET model
jj Josephson junction model

Parameter values are defined by appending the parameter name, as given for each model type, followed by an equal sign and the parameter value. Model parameters that are not given a value are generally assigned default values.

The show command with the -M option is useful for listing the parameters that can be specified to a model. Only the parameters not listed as ``RO'' (read-only) can appear in a .model line.

In the tables that follow, the various model parameters are listed. The ``units'' field of the tables provides the assumed units of measure for the parameter, which is expressed using symbols from the following table.

M meters
cM centimeters
$ \mu$M microns
S seconds
Hz hertz
F farads
H henries
$ \Omega$ ohms
C degrees Celsius
$ \Box$ square
A amperes
V volts
eV electron-volts
deg degrees



Subsections
next up previous contents index
Next: Analysis at Different Temperatures Up: WRspice Input Format Previous: Circuit Elements   Contents   Index
Stephen R. Whiteley 2017-11-08