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Simulators >> Circuit Simulators >> How to build a test-bench for mismatch simulation of fully differential opamp?
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Message started by Jacki on May 31^st, 2012, 2:13am

Title: How to build a test-bench for mismatch simulation of fully differential opamp?
Post by Jacki on May 31^st, 2012, 2:13am

Hello,

I am simulating an opamp with DC gain 70dB. I am troubled by the mismatch simulation now because I don't know how to build a good test bench for the fully differential opamp. Because the DC gain is large, small mismatch offset can drive the opamp to linear region. I also see some comments to simulate in a closed loop. But how to build the closed loop test bench, do the operating points burnt by the direct resistive feedback?

I also read the white paper "Functional verification of a differential operational amplifier". But still I cannot figure out the good test bench for Monte Carlo simulation. In Allen's book, the author onlys mentions fully differential input and single output architecture.

Can anybody give some comments or reference about the testbench?

Thanks.

Jacki

Title: Re: How to build a test-bench for mismatch simulation of fully differential opamp?
Post by Jacki on May 31^st, 2012, 3:14am

I know how it should work in a correct way. Mismatch is not important for the DC gain and phase margin, probably I should run corner simulation.

Title: Re: How to build a test-bench for mismatch simulation of fully differential opamp?
Post by pixel on May 31^st, 2012, 8:37am

You can use sp1twitch from analogLib. You can set the state of the switch for DC, AC , IC, and TRAN simulation.
For exampel for DC(IC) switch can be closed, and for AC opened.