@User @User I saw that you used nfet and pfet primitives in https://github.com/lakshmi-sathi/avsdpll_1v8/tree/main/Sky130_Primitives/cells . could I put standard cells to simulate inside ngspice ? https://github.com/google/skywater-pdk/tree/master/libraries/sky130_fd_sc_hd

I didn't get your question. Are you asking can we simulate fet using ngspice? The entire IP was simulated using ngspice

@promach If you mean simulating standard cells using ngspice, you can maybe take a look at the spice files provided in sky130_fd_sc_hd for the standard cell which you are interested in simulating.

@promach: Also, if you pull the latest version of Caravel, "develop" branch, I have under the ngspice/ directory an ngspice testbench simulation of the power-on-reset circuit, which contains standard cells from the sky130_fd_sc_hvl library as well as primitive devices.

@Tim Edwards What do you exactly mean by "latest version of Caravel, "develop" branch" ?

@promach: https://github.com/efabless/caravel/tree/develop/ngspice