I'm trying to understand how this AD8402 digital potentiometer works, I need it to be decoupled from the circuit it's driving, that is Vdd, GND and all logic inputs not connected in any way to A, B and W pins.
According to the figure 45 (page 20) of the datasheet I think I can safely connect a 5V power supply to the IC power pins and connect a completely different system (also 5V) on the A, B and W pins.
On page 11 however it seems that VA, VB and VW must be between VDD and GND...
Also on page 24:
Certain boundary conditions must be satisfied for proper AD8400/AD8402/AD8403 operation. First, all analog signals must remain within the GND to VDD range used to operate the single-supply AD8400/AD8402/AD8403.
My question is: can I connect the VDD and GND of my AD8402 to my 5V supply and regulate a potentiometer input on another device that supplies its own 5V and GND to the A and B pins, but without the GND of the AD8402 and the device being connected?