NGSpice (on linux): PMOS doesn't seem to work!

Thread Starter

spacewrench

Joined Oct 5, 2009
58
I'm trying to do some simple simulations on Linux (Ubuntu), and the easy_spice package seems to work pretty well, but I can't figure out how to get PMOS transistors working. I've tried them flipped D/S, with the base terminal connected to D or S, but they never turn on as I expect (when Vgs is negative). I'd appreciate it if anybody who understands this stuff can explain what I'm doing wrong in small words...

My test circuit:


The netlist:
* Spice netlister for gnetlist
R22 Out2 1 2.2k
R21 4 in 10
M3 1 in Out3 Out3 PCH L=1u W=200u
M4 Out3 in 6 6 NCH L=1u W=200u
R11 2 in 10
R12 3 Out1 2.2k
M2 Out2 4 5 5 NCH L=1u W=200u
M1 Out1 2 1 1 PCH L=1u W=200u
Vmeter3 6 0 0
Vsig in 0 PULSE 0 5 1uS 120nS 200nS 7uS 20uS
Vmeter2 5 0 0
Vmeter1 3 0 0
VDD 1 0 5
.END
The plot:
 
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