How to measure and improve PSRR in opamp design

tavakoli said:

it could be improved by using cascade cofigurations that shield the circuit from power supply ...

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dayang said:

Hello,
My target is to design a opamp in 180nm 1.8v power supply.The input and output need rail to rail.My question is about the PSRR,How to measure it(use a close loop configuration or a open loop configuration)? How to improve it(just simply increase the channel length? is there any guideline about it ? I have read the posts here but still not understand it clearly, Help!!

REGARDS

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Btrend said:

dayang said:

Hello,
My target is to design a opamp in 180nm 1.8v power supply.The input and output need rail to rail.My question is about the PSRR,How to measure it(use a close loop configuration or a open loop configuration)? How to improve it(just simply increase the channel length? is there any guideline about it ? I have read the posts here but still not understand it clearly, Help!!

REGARDS

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PSRR=20*log(ΔVout/ΔVcc)
so use closed loop, introduced AC signal at VCC and then probe Vout

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