How to compensate feedthrough&opamp offset voltage in S/

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k1gunner

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Hello!!
I'm desiging sample and hold with buffer amp(single ended).
I know there are big 3 issues in S/H.

1.charge injection
2.clock feedthrough
3.offset V at OPAMP

most of paper say how to cancel feedthrough and charge injection.
They don't say opamp offset voltage.

How to compensate 1,2,3 sametime?

could you recommend papers about compensaton feedthrough and offset both?

thanks..
 

Re: How to compensate feedthrough&opamp offset voltage i

k1gunner said:
... They don't say opamp offset voltage.
Click to expand...

With the switched caps in series with the opAmp's inputs - and the caps' inputs shortcut to the same voltage level - the caps hold the individual input voltages at both inputs, by this reproduce (cancel) the input offset voltage during the next sample period. So offset cancelling is done inherently with the switched cap (sample & hold) method.
 

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