rajath
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Hi Tosei, Sorry, did not realize there was a reply... I do not have a differential signal and the current configuration is a simple opamp with unity feedback (i'm still in the process of evaluating this architecture). In my first attempt, I had a two single MOS switches for both the input and the feedback signal respectively, which turn on and off. Hence, when the switch is off, the input of the amp goes floating. I know this is a bad idea but haven't understood why it results in high 1/f noise. Currently I have two switches for each line - one switch connects to the signal and the other to ground. The amp inputs are dragged to ground in the negative phase. I think the inverter noise appears because of the node being grounded in half the cycle. The noise decreases if I change this voltage from ground to a higher voltage like 200mV. Is this the best way to implement the switches? can I have a cross coupled switch between the two inputs of the amp - doesn't make much sense to me since the voltages would be very close in the two lines if the circuit is working fine... thanks in advance...
regards, rajath
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