Hello, I have some difficulties with spice simulation. I want simulate the input-output characteristic of a common source stage, with diode-connected load. My problem arises because the result of simulation is different from the characteristic (found on every book ) of a common source stage, with diode-connected load. In particoular, from the simulation, i see that the device NMOS amplifier, conducts even if its Vgs<Vth (the current in the simulation has a very great magnitude, so i don't think it's a current of weak inversion). Is this a problem of model of device?I attach a pdf with some images. The model i've used is the follow:
.MODEL nfet NMOS(LEVEL=1, KP=50u, VTO=0.7, LAMBDA=0.01,
+ GAMMA=0.5, PHI=0.7, TOX=15E-9,
+ CJ=4E-4, CJSW=1E-10, MJ=0.5, MJSW=0.5, PB=0.9,
+ CGSO=2.5E-10, CGDO=2.5E-10, CGBO=2.5E-10)
Can you help me? Thanks.
P.S. Excuse me for my english.
.MODEL nfet NMOS(LEVEL=1, KP=50u, VTO=0.7, LAMBDA=0.01,
+ GAMMA=0.5, PHI=0.7, TOX=15E-9,
+ CJ=4E-4, CJSW=1E-10, MJ=0.5, MJSW=0.5, PB=0.9,
+ CGSO=2.5E-10, CGDO=2.5E-10, CGBO=2.5E-10)
Can you help me? Thanks.
P.S. Excuse me for my english.
Attachments
-
25 KB Views: 9