The APV1121SXJ is a photodiode output optocoupler manufactured by Panasonic and is used to isolate communication systems from high voltages, digital logic, and sensitive analog signals. The optocoupler can be used in a variety of applications, including for photon detection, power control, and microprocessor monitoring. This optocoupler features a high photo-detection efficiency of 50%, meaning that it can accurately detect signals in a wide range of light sources. The APV1121SXJ also has a wide input frequency range of 0-16 MHz, and is capable of providing up to 5000Vrms of insulation. It also has a high surge immunity of 8kV, offering additional protection from voltage spikes.