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

Discussion in 'General Electronics Chat' started by spacewrench, May 27, 2010.

  1. spacewrench

    Thread Starter Member

    Oct 5, 2009
    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
    The plot: