| Resistor Model |
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.
| 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 |
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:
RTNOM = RSH · (L-NARROW)/(W-NARROW)
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:
RTEMP = RTNOM · R · 1.01TCE(TEMP-TNOM)
If TCE is not specified, then the resistance is given by:
RTEMP = RTNOM · R · (1+TC1(TEMP-TNOM)+TC2(TEMP-TNOM)2)
.MODEL RMOD R ( TC1=0.001 )
.MODEL RSEMI R ( RSH=100 NARROW=0.25u )