What the 1500 W peak pulse rating means on your bench
The 1.5SMC15AHM3/H is a 1500 W Zener TVS diode from Vishay's automotive-grade TransZorb® series, qualified to AEC-Q101. The clamping voltage at that pulse is 21.2 V, so a 12 V rail sees the surge clipped well below the downstream IC's absolute maximum. Breakdown is guaranteed between 14.3 V and the clamp at 21.2 V. For a 12 V automotive bus, this is the standard protection window: the TVS stays out of the circuit at nominal voltage but catches transients before they reach the ECU or sensor module.
AEC-Q101 and the DO-214AB package — what they mean for fit
The operating junction temperature range is -65°C to 150°C, so it handles the under-hood thermal cycle without derating the pulse power at the hot end. The DO-214AB (SMC) package is a standard surface-mount footprint — same as many other 1500 W TVS diodes, so a board already laid out for an SMC package accepts this part without a pad revision. The series label includes both 1.5SMC and TransZorb® — Vishay's trademark for their silicon-avalanche TVS construction. The base product number is 1.5SMC15, and the AHM3/H suffix indicates the AEC-Q101 automotive grade and the tape-and-reel packaging.