how to find i/p and o/p voltage swings(max and min)

[prashant_sharma]

Hello friends,
I am very confused on how to find out the maximum and minimum input and output voltage ranges for say a differential amplifier(NMOS) with active load (PMOS). Its like, I was reading grey, hurst book on Analog integr ckt design, but couldnt make out anything about my doubts. I am not anle to figure out like when a mosfet goes into crash, which one goes into crash and all that stuff. The knowledge of this would also help me find out the max and min common input volatge ranges.
Kindly help......

If possible please anyone could explain starting with finding the operating voltage ranges of a simple common source amplifier and graduate t a diff amp....

Another doubt thats bugging me is OPAMP stability analysis. I want to know abt phase margin and how to figure that out.

I know the above questions are too much, but its just that I am not able to figure out of books...
Thanks

Prashant[/img]

 

[deepa]

Well to calculate the swings ,u start from the basic equation Vd>Vg-Vt for the transistors to be in saturation.So from the top,u see the overdrive of the PMOS,hence the maximum voltage swing will be be Vdd-Vov.to find the minimum value u see the bottom NMOS transistors,it obviously cannot go down upto 0,hence it ll moslty be the overdrive of the NMOS transitors or any block of circuit below the point at which the output is taken.

 

[seanyang]

Try this:

 

[gingerjxb]

Phillip E. Allen's book has detailed description about opamp input/output swing measurement
-- CMOS Analog Circuit Design, Second Edition
good luck