In order to conclude whether the transistor is off or not we should check whether Vg<Vth rather than Vgs<Vth, is that right? Otherwise a wrong conclusion may result.
Also can someone point what does each "region" correspond to in dc operating point parameter. Like region=1≡cutoff,region=2≡saturation and region=2≡triode. Is that right?
In order to conclude whether the transistor is off or not we should check whether Vg<Vth rather than Vgs<Vth, is that right? Otherwise a wrong conclusion may result.
Also can someone point what does each "region" correspond to in dc operating point parameter. Like region=1≡cutoff,region=2≡saturation and region=2≡triode. Is that right?
So if vgs is a little less than vth and vds>vdsat, that corresponds to subthreshold region? What is the typical margin for "little less than"? Also what model you use to size your transistor in subthreshold?
Vgs>Vth is just an approximation of not being cutoff region. Vgs must be greater than Vth at least 50 mV to ensure it is in not cutoff region. Actually if Vgs just little greater or smaller than Vth, the device will enter sub-threshold region.
Furthermore, in complex model such as BSIM3 or 4, the boundary between every regions become very blurred, and usually appeared in continuously.
VGS is rather a correct measure because, the gate voltage relative to the source voltage
is what decides the inversion of the channel region, and not the absolute volatge of the
gate itself.....
Where can I see these numbers?? in output file?? if so, as i understood now, i can know from the SPICE output file the state of each MOSFET in the circuit.. am I right? how?? please show me an example or a snap shot or what ever as i was looking for this issue long time ago.
Note that i am using BSIM level 7 model..