# Unknown equation in the SPICE resistor model

I was looking for simple resistor spice model, and came across this:

parameters
+rsh = 40           dw = 0              dl = 0
+tc1 = 0            tc2 = 0             pvc1 = 0
+pvc2 = 0           pvc3 = 0
...
+teff = 1+tc1*temp+tc2*temp*temp
R0 ( p n ) resistor r=rsh*(l-dl)/(w-dw)*teff*(1+pvc1*(tanh(pvc2*abs(v(p,n)/(l-dl))+pvc3)-tanh(pvc3)))


Source

I am pretty familiar with almost all of typical resistor parameters, but I can't find any information about that particular resistance equation and any of the "pvc" parameters. Specially about this part:

(1+pvc1*(tanh(pvc2*abs(v(p,n)/(l-dl))+pvc3)-tanh(pvc3)))


Where does this equation come from? Where can I find out more about it?

UPD: This is probably on-silicon model

• So exactly where did you "come across" this model? Give us some context. – Elliot Alderson Sep 19 at 14:46
• given the 'rsh' which could be a resistance_sheet, this is an on-silicon model – analogsystemsrf Sep 19 at 16:39
• @analogsystemsrf I know about 'rsh' already, but i can't really find any information about the second part of the equation – user232380 Sep 20 at 4:28
• @Elliot Alderson princeton.edu/~nverma/cadenceSetup_6.1.7/gpdk090_v4.4/models/… I think that a 90 nm model from the gpdk library. – user232380 Sep 20 at 4:28