Hello QSpice community,
I defined my first symbol (opAmp_1stage.qsym) from a hierarchical schematic (opAmp_1stage.qsch).
When I run a simulation from a parent schematic (bench_opAmp_1stage.qsch) I encounter the warning
Didn't find a model for "NMOS•X1" -- defaults assumed
for each of the four NMOSs used inside the symbol.
You are using MOS with their default parameters. The reason why NMOS gives you a warning but not PMOS is that when you examine the library file properties, the default links for NMOS point to the NMOS.txt library and for PMOS point to the PMOS.txt library, both from the Qspice installation directory. If you inspect these two libraries, you will see that only PMOS has .model PMOS PMOS added. Therefore, the model name PMOS is defined as a PMOS through the PMOS.txt library, but not NMOS. This is why you need to include .model NMOS NMOS in the child schematic.
It’s a bit tricky as it seems that Mike allows NMOS without a .model NMOS NMOS in the parent schematic without issuing a warning. Anyway, with this warning or not, you still get the same result.
