CMOS Telescopic Operational amplifier Design

[mkpriya457]

I am designing a CMOS telescopic op amp. But i am getting very low CMRR. i.e CMRR below 10.Will it be the problem of the design?

 

[daniel1]

Hi,

It could be because of your CMFB if you are using one, or it could be because your design is not optimized. Describe your problem more clearly ...

 

[mkpriya457]

I am getting almost similar common mode and difference mode gain. So I get very low CMRR.

 

[daniel1]

As you might know, the common mode gain is expected to be small whereas the differential gain should be high. You can modify your circuit to increase the gain, increase input transistor w/l.
Check this thread.
https://www.edaboard.com/threads/104508/