The SMAJ440A is a unidirectional transient voltage suppressor diode designed for surge and ESD protection in portable communications, computing, and video equipment. It features a working peak reverse voltage of 440 V with a breakdown voltage range of 489 to 539 V, housed in a compact DO-214AC (SMA) surface mount package. The device delivers 400 watts peak pulse power dissipation at 1 ms pulse width and maintains steady-state power dissipation of 1.0 watt at 75°C lead temperature. With fast response times of less than 1.0 picosecond and maximum clamping voltage of 713 V at 820 µs pulse width, the SMAJ440A provides reliable protection against transient overvoltages in IEC 61000-4-2 ESD, IEC 61000-4-4 EFT, and IEC 61000-4-5 surge applications. The device is RoHS compliant and UL recognized, making it suitable for demanding industrial and consumer electronics applications.