Device identity and key ratings
The 1.5SMC540A-M3/57T is a Zener-type TVS diode from Vishay's 1.5SMC TransZorb series, designed for general-purpose surge protection. Despite the 'Zener' type label, this is a transient-voltage-suppression diode — it clamps fast overvoltage transients, not a standard voltage-regulator Zener.
Supplied in Tape & Reel (TR) for automated pick-and-place. The package footprint is standard for the SMC family, so pad layouts are interchangeable with other 1500 W SMC TVS diodes from Vishay or competitors.
