Type Name: 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 (multiple names are aliases) available are:
Resistor Model Parameters name parameter units default example tc1, tc, tc1r first order temperature coeff. /C
0.0 - tc2, tc2r second order temperature coeff. /C2
0.0 - rsh sheet resistance /
- 50 defl, l default length M 0 2e-6 defw, w default width M 0 2e-6 dl, dlr length reduction due to etching M 0 1e-7 narrow, dw narrowing due to side etching M 0 1e-7 tnom, tref parameter measurement temperature C 25 50 temp default instance temperature C 25 50 kf flicker noise coefficient 0 af flicker noise exponent of current 2 ef flicker noise exponent of frequency 1 wf flicker noise exponent of width 1 lf flicker noise exponent of length 1
The sheet resistance is used with the etch reduction parameters and l and w from the resistor element line to determine the nominal resistance by the formula
R = rsh . (l - dl)/(w - narrow).
The parameters defw and defl are used to supply default values for element w and l if not specified on the device line. A fatal error is produced if the resistance can't be determined from given parameters.
After the nominal resistance is calculated, it is adjusted for temperature by the formula:
R(temp) = R(tnom) . (1 + tc1 . (temp-tnom) + tc2 . (temp-tnom)2)
The flicker noise capability can be used in noise analysis. This requires that kf, l, and w be specified. To use, the instance line must reference a model, but also can have a resistance specified which will override model calculation of resistance.
Flicker noise model:
Noise = (KF . IAF)/(LeffLF . WeffWF . fEF)
Param | Description | Units |
---|---|---|
Noise | Noise spectrum density | A2Hz |
I | Current | A |
Leff | Eff length (L-DL) | M |
Weff | Eff width (W-DW) | M |
f | Frequency | Hz |
Param | Description | Default, Range |
KF | Flicker noise coefficient | 0, > = 0 |
AF | Exponent of current | 2, > 0 |
LF | Exp. of eff. length | 1, > 0 |
WF | Exp. of eff. width | 1, > 0 |
EF | Exp. of frequency | 1, > 0 |