Isolated error amplifiers feature programmable shunt references

Unique to this pair of devices is the capability of the error amplifier and shunt reference to operate down to 1.6V, the industry’s lowest level, enabling higher efficiency, isolated low voltage power supply designs. The LIA135 and LIA136 offers a 1.299V internal precision voltage reference with a very low 0.5% tolerance for improved power supply accuracy.

Optically isolated error amplifiers are important integrated devices for secondary to primary side feedback in AC/DC power supplies and DC/DC converters. These optical devices save board space and replace bulky transformer secondary feedback circuits. The LIA135 and LIA136 combination of features are optimal for use in isolated power supply design as the bias current for the shunt regulators does not pass through the LED. This eliminates bias-related optical current, providing the user with the industry’s largest dynamic range (1000:1).

The optocoupler portions of the LIA135 and LIA136 comprise of infrared LEDs that are optically coupled to NPN phototransistors. The optocouplers' current transfer ratio is between 500 and 2000%. The LIA136 offers enhanced performance characteristics and an extended operational temperature range to 110ºC.