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
l	Inductor 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