@User xschem just provides a netlist to ngspice, the problem is how to speed up ngspice. Of course you can set reasonable values for the timestep in the .tran comand and reduce the number of saved variables. There is a considerable time spent by ngspice parsing the skywater-pdk models, This can be accelerated by creating a

.spiceinit

file in the directory the simulator is running (if you are using xschem and did not change defaults it is

~/.xschem/simulations

). the

.spiceinit

has the following content:

set ngbehavior=hsa

set ng_nomodcheck

this forces ngspice to use hspice compatibility mode and not load and parse unused model corners. this speeds up parsing significantly.

I actually have the .spiceinit file with above commands in. It still takes a lot of time. 😅

yes the .spiceinit mitigates the problem but ngspice is taking some time for parsing. On my system ngsice takes 30/35 seconds to get the models in and start doing the actual simulation work...