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offset voltage compensation

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nabardwell:
I have been looking for an op amp that is stable with av=2.25 ish frequency to 100mhz the op amp also has to have very very good large signal response 2VPP at av~2.25 100mhz. It is appropriate to assume RL~1Mohm so 1k AV=2 vs Freq can be ignored and no load scenario can be assumed. I have found a suitable op amp LM7171 but with the large gain intended 4 stages of AV 2.25 the input offset voltage of ~100uV will be too much. I have simulated and tested a unity gain offset voltage compensated op amp with both low impedance offset source and voltage divider offset source. While I am able to get very good offset for a specific voltage the drift over the entire range is quite large and essentially equivalent to the original offset voltage. Does any one have any suggestions on how to get less drift over the entire range.

Here at 2v we have very good offset adjustment


Here at -2v we are pretty far out

Vovk_Z:
All high-speed opamps have about 1 mV offset or more. You can adjust it for some temperature but can't adjust it for all temperature range, except you use additional integrator.
If you don't need 0 Hz (DC) then may be you may use a capacitor at the output?

nabardwell:
I was planning on being able to amplify both ac and dc signals. The overall gain after 4 stages will be x25 and if I cant compensate the offset voltage on the first two stages to be better than ~50uV I will have over 1.25 mv on the output from the offset voltage. I am most concerned about the offset drift over Vin when I add offset compensation I get a large offset variation over the Vin range +-2v.

Vovk_Z:
I think you should look an Art of Electronix  great book. There is an example of how to calculate opamp circuits error budget (and ways to compensate offset). Because I'm not sure you can simulate circuit you want before you'll understand how to do.

mycroft:
You can use a composite amplifier where a slow op amp handles the offset compensation of a fast op amp. Take a look at Composite Amplifiers by Jim William in LT AN-21 (https://www.analog.com/media/en/technical-documentation/application-notes/an21f.pdf).

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