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Design >> Analog Design >> biase voltage of opamp in pipelin adc
https://designers-guide.org/forum/YaBB.pl?num=1239201766

Message started by frankdhz on Apr 8^th, 2009, 7:42am

Title: biase voltage of opamp in pipelin adc
Post by frankdhz on Apr 8^th, 2009, 7:42am

After changing from sample phase to amplify phase ,the Cs and Cf disconnect from input common voltage of the opamp in the MDAC .
How dose the input DC biase voltage can be sustained during the amplify phase?

Title: Re: biase voltage of opamp in pipelin adc
Post by rf-design on Apr 11^th, 2009, 2:14am

I could not imagine how the amplifying SC circuit make a floating connection to the opamp inputs.

General the inputs of the opamp must have a specific potential. Otherwise the common mode input voltage drift with a period and more critical the output is undefined. If your SC-circuit does not need the opamp in a phase switch it off.

Please post a schematic.