The SMA4F39AH from Taiwan Semiconductor is a unidirectional Electrostatic Discharge (ESD) Suppressor / Transient Voltage Suppressor (TVS) Diode with a maximum power rating of 400 Watts. It has a working voltage of 45.9 Volts, with a 5% tolerance, and a breakdown voltage of 65.2V. It offers optimal protection against overvoltage and is designed to produce low capacitance and low clamping voltage. It can be used in different types of ESD-sensitive electronic interfaces and devices, such as USB, MMC, and SPI, and it is suitable for handheld devices, medical instruments, industrial controllers, and other similar applications.