Isolated error amplifiers outperform optocouplers and shunt regulators in power supply applications

February 26, 2013 // By Paul Buckley
Analog Devices, Inc. has introduced isolated error amplifiers that provide power supply designers with a higher performing, single-chip alternative to isolation techniques based on optocouplers and shunt regulators.

Designed for linear feedback power supplies using primary side controllers, the ADuM3190 and ADuM4190 isolated error amplifiers have a 400-kHz bandwidth, with 0.5% typical initial accuracy at 25°C and 1% total accuracy over the extended temperature range of –40 to +125˚C. This provides manufacturers of ac-to-dc and dc-to-dc power supplies, including those that are DOSA (Distributed-power Open Standards Alliance)-compliant, with an upgrade in speed and operating temperature range, as well as a 5× improvement in transient response.

Designed with ADI’s iCoupler digital isolation technology, the ADuM3190 and ADuM4190 eliminate the CTR (current-transfer ratio) of optocouplers that degrades over the lifetime of the devices and limits operation to 85˚C. The ADuM3190 and ADuM4190 include a highly accurate 1.225-V reference and a wideband operational amplifier that can be used to set up a variety of commonly used power supply loop compensation techniques.


The ADuM3190 parts are all available now with the ADuM4190 parts being available in April 2013.

More information about the ADuM3190 and ADuM4190 isolated error amplifiers at and