Analog Devices ADuM3190/4190 High Stability Isolated Error Amplifier is based on ADI iCoupler® technology and is ideal for linear feedback power supplies with primary side controllers enabling improvements in transient response, power density, and stability as compared to commonly used optocoupler and shunt regulator solutions. Unlike optocoupler-based solutions, which have an uncertain current-transfer-ratio over lifetime and at high temperatures, ADuM3190/4190's transfer function does not change over lifetime and is stable over a wide temperature range of -40°C to 125°C. Included is a wide band operational amplifier that can be used to set up a variety of commonly used power supply loop compensation techniques. ADuM3190/4190 is fast enough to allow a feedback loop to react to fast transient conditions and over current conditions. The device also includes a high accuracy 1.225V reference to compare with the supply output set point.