Q
Can ADUC845 analogue supply be shut down leaving digital supply on?
A
No, this is not recommended, referring to page 88 of the D/S , section
"POWER-ON RESET OPERATION" : below 2.63 volts the IC will be held in reset.
Also the internal voltage reference would lose its power and so it would need a
warm-up period in order for it to stabilize.