Question
I need to convert an analog signal (sine) with range (0.6V to 4.6V). Is it
possible to supply the analog power of the AD7859 with +5V and the digital
power of the AD7859 with +3.3V (in order to be compliant with input/output DSP
signal level) ?
Answer
By using an external 4V reference and powering the device for a +5V supply you
will be able to measure a voltage range from 0.6V to 4.6V.
However, the absolute maximum ratings state that AVDD and DVDD must be within
0.3V of each other, so you must power the digital side from +5V also. You can
then level shift the 5V logic signals using external circuitry between the
AD7859 and the DSP.