Question
How different can Vdd and Vlogic be?
Answer
Vdd is used as a reference signal for ESD protection. No other supply voltage
can be higher than VDD so Vlogic maximum voltage is limited to Vdd.
AD5121
Production
The AD5121/AD5141 potentiometers provide a nonvolatile
solution for 128-/256-position adjustment applications, offering
guaranteed low resistor tolerance...
Datasheet
AD5121 on Analog.com