Hi, I have an ngspice related question for when I am running my xschem netlists: the transient simulation crashes with an error "doAnalyses: TRAN: Timestep too small; time = 6.445e-05, timestep=1.25e-20" when I increase the size of my transistors. It seems to happen at random when I increase the multiplier or the width above 100. is there any way to fix this? Or is it telling me that I cannot use such large transistors?

it probably cant simulate that case because transition is too fast? Try reducing the simulation step? There is not enough information provided to help you debug this. Can you post the schematics? Unless somebody more experienced can suggest a solution.

I think I found sort of a fix to this problem. When I used the additional command "optran 0 0 0 tstep tstop 0", skips the original op iteration and doesn't have this error. Not sure if this will make the results less accurate?