#164 MOSFET PSP model usage of NF parameter Issue created by hpretl When I do a simple testbench in ngspice simulating just a single LV-NMOS (I assume it is the same for PMOS and HV variants, but I have not checked it), I see that the model parameter

rg

is not reacting to the number of fingers I set. This is not ideal, as the PSP model can model extrinsic resistances. From the PSP model doc: image The calculation of

rg

is: image In the model file of IHP's PDK, the PSP model is instantiated like that: image This means that essentially the

nf

(number of fingers, here called

ng

, which is not consistent) parameter is never passed on to the PSP model, instead only the width of a single finger is used in the model, and the multiplier parameter

m

is then increased by

nf

as passed on to the model as

mult=ng*m

. In this way, the intrinsic model does not know about the true

nf

and

m

parameters. This is also confirmed by looking at the model parameters in ngspice, which always shows

nf=1

. Maybe this can be changed in a future release? It looks like some capabilities of the PSP model are bypassed in this way. IHP-GmbH/IHP-Open-PDK