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AD7176-2 ADC Reference Voltage

Question asked by iozana on Jul 23, 2017
Latest reply on Jul 23, 2017 by JinoL


I/m trying to get a better understanding about the ADC reference voltage…

Let's say I'm having a fully-differential input signal with 1V to 4V amplitude, 180 degree phase from each other, and common mode of 2.5V (differential voltage is 3V) (see attached file). Can I configure the ADC to work with internal reference of 2.5V? I'm gassing that the answer is no because the differential input voltage range must be within the +/-VREF (which is +/-2.5V).

When the ADC is working from 5V reference, what will be the ADC digital reading when the input signals are at 2.5V? (Differential voltage is 0V- both line are united at 2.5V). What will be the ADC digital reading at 4V? (Differential voltage is 3V- the positive input voltage is at 4V and the negative is at 1.5V).