The OPI110A is a 1-channel 4-pin Optically Coupled Isolator contains an infrared light emitting diode (LED) and a NPN silicon photo sensor. It has 890nm light emitting diode (LED) and NPN phototransistor sensor. The device is sealed in a precast opaque housing with an optically transmissive path between the LED and the photo sensor. It is designed for transmission of information between one power supply voltage and another where the potentials during surge conditions are not greater than the guaranteed isolation voltage. It is suitable for electrical isolation in dirty environments, high voltage isolation between input and output.