gongyuwei
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Hi, in past months I designed a data acquisition circuit, in which a 100M 12 bits ADC was used. Now, I am debugging it. I captured the output data of ADC and found some noise in it. The ADC is AD9628. Its input is differential. I connected the positive and negative input of ADC. The data captured was very good. Only one bit variation existed in ADC output. There are two stage amplifier before ADC. The first one is a VGA VCA824, and the second is a full differential amplifier ADA4927. So the noise in the output of ADC should come from the two stage. when I connected the input of the first stage to ground, noise is about 10 bits. It means that the noise is about 1-2mV. Can the noise generated by amplifiers reach this value? or the noise comes the crosstalk of nearby ICs? Are there some methods to reduce the noise of amplifiers?
Thank you!
Thank you!