How to determine attenuation divider for Differential input to AD7264?



For our application, we are using AD7264 as input stage.

The AD7264 will be fed with four analogue differential channels:

  1. 0 Vdc to 100 Vdc - two channels
  2. 0 Vdc to 10 Vdc - two channels


Datasheet defines two specific values for Vcm range

2 V for PGA = 1

(AVcc / 2) for 2 <= PGA <= 128


1. How to identify the "Vcm" run-time?

2. How to design the incoming differential signal attenuator if no Vcm is specified?

3. If Vcm is specified to be zero, how the ADC would handle -ve signal range as per the equation:

Analogue input range = (Vcm) +- (Vref / (2 x Gain)) and single +5 V supply operation?


Best regards,