The Vishay 1.5SMC440A-M3/9AT is a Zener-type TVS diode from the 1.5SMC, TransZorb® series, delivering 1500W (1.5kW) of peak pulse power across a 10/1000µs waveform. Rated for a reverse standoff voltage of 376V and a minimum breakdown of 418V, it clamps transients to 602V maximum at the rated peak pulse current of 2.5A. The single unidirectional channel protects a single rail or signal line against overvoltage events in general-purpose industrial and commercial equipment.
Clamping voltage and pulse current — the real protection envelope
Power line protection is not enabled — this device is intended for signal or low-voltage DC rail clamping, not for mains AC or high-energy surge suppression on power distribution lines.