Hi , I am developing circuit for 3 phase AC 220V measurement . No current measurement needed . Only voltages ( against common neutral ) . I was considering to use Si890X since it has 3 AINP. Can I use only one chip for all 3 phases , or do I have to use separate one for each phase ? Also I plan to use similar front op-amp circuit as used in evaluation boards,
You should be able to use a single chip, as long as you have adequate attenuation followed by input amplifiers.