The SMA4F12AH is an ESD suppressor/TVS diode manufactured by Taiwan Semiconductor. It features a 400W rating, 14.1V working voltage, 5% peak pulse power, unidirectional design, and is suitable for suppressing electrostatic discharge events. The component is made up of a metal–oxide–semiconductor field-effect transistor (MOSFET) between two zener diodes, which act as a bidirectional clamp for voltage exceeding a specified breakdown voltage. It has a breakdown voltage ranging from 15.0 to 57.0 Volts. The component also includes an ultra-low (typically less than 1 pF), effective capacitance for ESD protection. The SMA4F12AH is ideal for ESD protection in sensitive circuit elements such as I/O ports, computer peripherals, and communication lines.