Hi,
I simulated a single NMOS in saturation.The saturation current is 2.13mA.For the same setup I introduced a volatage at the bulkand source at gnd in my NMOS.Ideally the current should decrease as Vth increases.But the simulation results speak:-
1.When there was no body effect Id = 2.13mA
2.The current increases to 4mA max, when the bulk volatge is = 700mV and after that it started decreasing.FInally at Vbulk=3V the current reduced to a very low value.

What has caused that sudden increase in the saturation current?Is it that that Isubstrate is not considered in normal mos current equation?
Why my device follwed the theory of Id-decrease with Vbulk after 700mV and not immediately.

Thanks in advance.
V

Thanks,
The link is of good help.My actual doubt for the setup was i needed an explanation for the following setup:-

the set up is :- single stage amplifier is before a differential amplifier. The single stage amplifier (CS) has its source and bulk connected to ground to have no body bias effect.
The next stage differential amplifier would in that case have its bulk already connected to ground,as in a n-well process all nmos share the same substrate.
My question is in that case there would be a body bias effect in the DA?If the source and bulk in the DA is connected together and then connected to a tail current source.
If the single stage CS has its bulk grounded then in fabrication the bulk of the DA would also be at ground.
So what is the preferred configuration:-
1.Source and bulk connected together to a tail current source?
2.Since the bulk would in the process of fabrication be connected to ground we consider the bulk at ground and then simulate?
Thanks in advance.
V

Thank you very much.
Regrads,
V.