change over temperature and from part to part?
An optocoupler has a current transfer ratio (CTR) that can change from part to
part and with temperature. The ADuM3190/4190 are a digital isolators with very
high gain and stability, and do not have a CTR characteristic that can vary
with time and temperature. The Gain of the ADuM3190/4190 from COMP to EAOUT is
expressed as 1V/V with 10% specification, but when used as an error amplifier
in a closed loop, the high gain of the internal Op Amp will maintain a very
stable EAOUT with time and temperature, and from part to part.