The model accepts, for compatibility with other simulation software, either R
or RES.

.MODEL <model name> R [model parameters] .MODEL <model name> RES [model parameters]

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.

Parameters

Parameter

Description

Default

Units

R

Resistance multiplier.

1.0

RSH

Sheet resistance.

0.0

Ω/square

DEFW

Default width. If width is not specified on device
line, then it is taken from the default width given in the model.

10e-6

m

NARROW

Narrowing due to side etching.

0.0

m

TC1

Is the linear temperature coefficient and is
sometimes given in data sheets as parts per million per °C. To convert
ppm specs to TC1 divide by 1E6.

0.0

Ω/°C

TC2

Quadratic temperature coefficient.

0.0

Ω/°C²

TCE

Exponential temperature coefficient.

0.0

%/°C

TNOM

Temperature at which the model parameters were
measured. If this value is specified overrides the nominal TNOM value
which is set in the options.

°C

TABS

Specifies the temperature at which the component
operates. This value, if specified, takes precedence over the analysis
temperature.

°C

TREL

Device temperature relative to current temperature.
If this parameter is specified but not the parameter TABS then the
current temperature of the component is equal to the current temperature
plus TREL.

°C

Semiconductor resistors

If resistance value is omitted from device line, then the sheet resistance is
used with the narrowing parameter and L and W from the resistor device to
determine the nominal resistance:

R_{TNOM} = RSH · (L-NARROW)/(W-NARROW)

Temperature effects

There are two different temperature factors, a quadratic factor and an
exponential factor. The quadratic factor is characterized by the model
parameters TC1 and TC2, or tc1 and tc2 from the device line. The exponential
factor is characterized by the model parameter TCE.

If TCE is specified, then the resistance is given by:

R_{TEMP} = R_{TNOM} · R · 1.01^{TCE(TEMP-TNOM)}

If TCE is not specified, then the resistance is given by:

R_{TEMP} = R_{TNOM} · R ·
(1+TC1(TEMP-TNOM)+TC2(TEMP-TNOM)^{2})

Examples

.MODEL RMOD R ( TC1=0.001 )
.MODEL RSEMI R ( RSH=100 NARROW=0.25u )