Toshiba has introduced two photorelays in  4-pin SO6 packages, for security systems, building automation and other industrial equipment. The devices, designated TLP170AM and TLP170GM, have a trigger LED current of 1mA, which reduces input side power loss by increasing the sensitivity of the photodiode array. Using these photorelays for ON/OFF control in battery-powered security devices ...

This story continues at Photorelays have trigger LED current of 1mA

Or just read more coverage at Electronics Weekly