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how to immprove phase margin- ota

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satyanitt

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SIR,
im designing an OTA telescopic wid certain gain enchancement modification architecture wid current mirror technique crosscoupled....in .018 technology...
i got my gain enchanced by 6 db bt my phase margin got very much decreased to 54 from 78.... what shud i do to bring pm to more than 60 ...i took currents as 200uA for the ota...suggest me few thngs...plz
 

Pls post the detail structure and load conditions.
 

my spec is load capacitance is 2pf Screenshot.png
 

why not increase the load capacitors? You can also reduce the ratio of the mirror branch to the ota branch to reduce the capacitance at the NMOS cascode node - this is your non-dominant pole. You may also want to increase the gm of the NMOS cascode devices.
 

Yes. I also suggest increasing output capacitor.
And please try to add series-connected resistor on output capacitor.
 

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