KT/C noise of switch in switched capacitor circuits

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minxin_zhou

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Can anybody tell me why the KT/C noise induced by switches in switched capacitor circuits can be eliminated by differencial configuration? It is well known that the offset and 1/f noise can be eliminated by CDS(corelated double sampling) technique. But why this noise can also be cancelled?
 

I do not think those noise can be eliminated.
Differential structure give good psrr and suppress common mode noise.
 

differential configuration will not reduce kT/C noise
 


The thermal noise is not eliminated by using differencial configuration. It is allways there. You can only increase the capacitor to make it lower of using a lower signal bandwith.

Bastos
 

I found in some literatures that the KT/C noise induced by switches can also been first orderly cancelled using the CDS technique. I am confused with that conclusion since I think the thermal can not be eliminated. The reference is below:
**broken link removed**

Please see page NO.12.
 

The link doesn't work.
 

of course can not
 

diffrential configuration sometimes boubles kt/C noise, never reduce.
 

kT/C noise power will double using differential structure, but the voltage swing will be double also thus induced 4x in signal power, so SNR improved by 3 dB compared to single-ended one.
 

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