The CNY174M with Transistor Output Optocouplers Optocoupler HI Bvceo Phototransistor is a high-speed, high-isolation, optically-coupled isolator designed and manufactured by ON Semiconductor. It is composed of an infrared LED optically coupled to a high-gain, high-Bvceo phototransistor separated by an insulated DIP package. This optocoupler is most commonly used for applications that require electrical isolation between two circuits such as isolated data transmitting, AC/DC voltage conversion, switch isolation, and low power logic isolation. This optocoupler also offers excellent common mode and transient noise rejection, and can withstand a wide range of temperatures (-55°C to 125°C).