From the specified common mode range it should be possible to operate the
AD7788/90 on Vdd = +5V as follows:
REFIN- connected to GND, REFIN+ conneceted to VDD/2.
AIN- is connected to GND, AIN+ is the input for a voltage derived from Vdd by a
variable resistive divider, and is in the range of 0V...+5V.
If the input overloaded?
Do we have to expect restrictions on accuracy from the offset? If yes, by what
degree and above/below of which limits?
The inputs of these devices are DIFFERENTIAL.
If you ground AIN- then you can only use the positive
half-scale at unity gain since AIN+ may not be more
than 30mV below the negative rail - and Vin(max) will
be +2.5 V and you will lose the lower half of the
5 V span.
If you want a 0-5 V span you must bias AIN- to +2.5V
and apply 0 - +5 V to AIN+.
The offset of these devices is 3 uV so should not
be a problem.