Effect of mos fingering in schematic simulation

[jdp721]

Hi.

Can anyone pls tell about the effect of mos fingering in schematic simulation?

Like if I have a mosfet with fixed (w / l) and change its no. of fingers, how does the device parameters change (if any) ?

 

[erikl]

Usually parasitics are not included in schematic models. So no effect resp. finger or multiplication factor. Just the total w counts.

 

[Dominik Przyborowski]

It depends to model but the following parameters are change: gate resistance, gate capacitance (due to overlap capacitances), drain/source resistance.
Changing finger width from very wide to narrow one could also affects transconductance.

 

[mtwieg]

Getting the real effects of fingering will probably only show if you do layout extraction.