As mentioned earlier query , the ADC is powered off the voltage as Vs pin. All level shifting of the shunt voltage from VCM to ground level for internal ADC is done internally. All error effects from power supply (PSRR), VCM (CMRR), and temperature are characterized and specified in the electrical specification table.
If VS is the power supply for ADC, Is there any internal reference voltage used for ADC (Since Vs may vary ~ 3.2V to 3.5V , Does it affect the Voltage & current accuracy)