The CH301A from ISOCOM is a Space Qualified Optocoupler with Forward Voltage 1.5 V, Continuous Current 15 mA, Collector-Emitter Dark Current 100 uA, Collector-Emitter Saturation Voltage 0.25 V, Operating Temperature -55 to 125 Degree C. Tags: Through Hole. More details for CH301A can be seen below.