May be it is inappropriate to ask this question here, so please accept my apologies. I have a simple CMOS Schmidtt trigger SPICE netlist that I had originally created using NMOS/PMOS Level 3, and everything worked just fine. Recently, I experimented with using the BSIM4 NMOS/ PMOS models with the same circuit, and everything went haywire - output looks absurd. Any hints/suggestions as to what I might be doing incorrectly would be extremely valuable. Thanks in advance for your help.