I'm trying to simulate a large pmos ( based on

sky130_fd_pr__pfet_01v8

model ) that I want to use as a power gate, however when I try to raise the number of fingers, the sim refuses to work. I thought havening 10-20 fingers for a power switch wouldn't be that big a deal.

Remember, increasing the number of fingers does not change the total equivalent size of the gate. It will just decrease the size of each individual gate. For example,

W=10 L=0.1 nf=10

is 10

W=1 L=0.1

gates in parallel.

W=10 L=0.1 nf=100

is 100

W=0.1 L=0.1

gates in parallel. In either case, the effective size of the transistor is

W=10 L=0.1

. If you want to increase the fingers without changing the size of the individual gates, be sure to increase

W

accordingly.

Oh ! Thanks, I wasn't aware of that !