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Oscillations at a phase margin of 90?

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What's the structure for your buffer? It is simple source follower or other structure. I am interested in your compensation cap. Please keep in mind some compensation cap will introduce hidden loops.
 

What do you mean by some compensation cap will introduce hidden loops?
 

some thing like Cgd in a mosfet...

I mean though its not a compensation cap... but its kind of feedback... and miller is something similar
 

I'm using a buffer connected OTA
 

Is this a single-ended or fully differential Opamp?

I am sure you know this well, but just a reminder: if it's a fully differential design then the CMFB loop can be oscillating.

Is this the case?
 

Most probably it isn't a fully differential diff pair, it isn't used as an input stage of LDO EA , is it ?
 

The buffer is a single ended OTA. It is used to drive the pass device, not the EA.
 

Are you still getting oscillations...
... like in one of ur previous posts u said you have found the solution...

And did you look for the pole zero plot?
 

I don't have oscillations now, after I've done the solution or it wouldn't have been a solution :D.

I didn't do yet the pole-zero plot, but its on my schedule.
 

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