In the last datasheet of the AD7656, figure 36 was added presenting protection diodes over the Vdd power pins.
Vdd limits are not specifically specified in the datasheet, however a value of 5V is legal.
But what about [5V - Vdiode] ? (as Vdiode can reach 0.3-0.4V even for a schottky diode)
Does when using such diodes I can not use any more my 5V supplier, and I need a different power supplier
which can guarantee Vdd is at least 5V at the AD7656 pin?