Hello.
I am working on making data acquisition card with AD7768 with +5V ref voltage. This ADC has dedicated pin for applying 2.5V (configurable when working in SPI control mode) to input signals. Some other ADCs also has this pin or any other source of this kind of voltage and every time I see it is connected to input signals by 2 resistors as shown on the screenshot.
Typically these resistors are 1k or 10k. Does this voltage should set the level for input signal to oscillate around for ? If yes I don't know what am I doing wrong in the LTSpice simulation but it's not having any effect.
If my assumptions are wrong, what is the purpouse of this VCM voltage?