In page 3 of the datasheet, the specification indicates that the analog input
can be 0~2*REFin. The condition is AVDD/VDRIVE=4.75~5.25V. It requires both
AVDD and VDRIVE to be 5V. However, in the datasheet, it says the Vdrive can be
3V to interface 3V MCU even at AVDD = 5V. Whether the VDRIVE needs to be 5V as
well when he choose 0~2*REFin input range. I used 3V MCU in the system.
There is no need to use the same voltage value for both supplies. The AVDD
should be tied to 4.75-5.25 V but VDRIVE pin can be connected to lower voltage,
for example 3 V.