Buffer Op Amp to Analog-to-Digital Converter Design: AC Coupled Differential Input, Single Supply, Single-Ended Op Amps, Differential Input to ADC

Problem:
How do I buffer the input of an Analog to Digital Converter (ADC) when I have an AC coupled differential input, single power supply, single-ended op amps, and differential input to ADC?

Solution:


Double click on schematic to enlarge.

Resistors R1 through R4 determine inverting gain for the top and bottom op amps. The common mode voltage from the ADC is coupled to both op amp stages as their virtual ground. There is no dc return, so there is no dc gain. Capacitors C1 and C2 are coupling capacitors. R5, R6, C3, and C4 are ADC compensation components.