UtpalT

Differential Input range and Front end designing for AD7264

Discussion created by UtpalT on Aug 17, 2016

Hello,

 

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,

--Utpal

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