@Stefan Schippers Is there a way to check the gain variation across temp and process in xschem, if so can you pls provide some testbench. Also can you show how to do pole zero analysis in ngspice. Thank you.

The following command sequence does an operating point analysis at 30C and then performs DC, TRAN, AC analyses at 30C, -40C, 125C, appending all the results in the same raw file.

.control
  option temp=30
  save all
  op
  write cmos_example_ngspice.raw
  set appendwrite
  dc vminus 2.3 2.7 0.001
  remzerovec
  write cmos_example_ngspice.raw
  tran 0.5n 5u
  remzerovec
  write cmos_example_ngspice.raw
  ac dec 10 1 1G
  remzerovec
  write cmos_example_ngspice.raw

  option temp=-40
  save all
  dc vminus 2.4 2.6 0.001
  remzerovec
  write cmos_example_ngspice.raw
  tran 0.5n 5u
  remzerovec
  write cmos_example_ngspice.raw
  ac dec 10 1 1G
  remzerovec
  write cmos_example_ngspice.raw

  option temp=125
  save all
  dc vminus 2.3 2.7 0.001
  remzerovec
  write cmos_example_ngspice.raw
  tran 0.5n 5u
  remzerovec
  write cmos_example_ngspice.raw
  ac dec 10 1 1G
  remzerovec
  write cmos_example_ngspice.raw
.endc

To my knowledge there is no way to change the process corner in a single ngspice run. You can however repeat the simulation changing the process corner and appending results to the same raw file by setting

set appendwrite

on following runs, (but clearing this setting on the first run!). For pole zero analysis this is more a ngspice question. Please see the

.pz

command in ngspice manual: 11.3.6 .PZ: Pole-Zero Analysis

In a previous word doc I sent you, you can use the .tcl scripts to change process. My advice is run those with the above analysis.

You can run across many conditions , using only one setup file. through CACE. Here's an example:

<https://cace.readthedocs.io/en/latest/tutorial/index.html>

Thank @Ahmed Reda This is very useful. It contains testbench too