Isolated error amplifiers said to outperform optocouplers

Analog Devices has introduced two new isolated error amplifiers, which it claims 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 have a 400kHz bandwidth, with 0.5% typical initial accuracy at 25°C and 1% total accuracy over the extended temperature range of –40 to 125°C. The company says this provides manufacturers of ac/dc and dc/dc power supplies, including those that are DOSA (Distributed-power Open Standards Alliance) compliant, with a significant upgrade in speed and operating temperature range, as well as a 5x improvement in transient response. Designed with ADI's iCoupler? digital isolation technology, the ADuM3190 and ADuM4190 eliminate the current transfer ratio of optocouplers that degrades over the lifetime of the devices and limits operation to 85°C. Both devices include a 1.225V reference and a wideband operational amplifier that can be used to set up a range of commonly used power supply loop compensation techniques.