The STMicroelectronics SM15T75AY is a unidirectional Zener TVS diode rated for 1500W peak pulse power (10/1000µs waveform), with a reverse standoff voltage of 64.1V and a minimum breakdown of 71.3V. This is the voltage tier for protecting 48V to 60V nominal rails — think automotive load-dump, alternator field decay, or high-side battery-line transients in an ECU or junction box. The 1500W rating means it absorbs a substantial single-pulse energy without failing short, but the 8/20µs current rating of 75A is the real-world surge capability for the shorter pulses typical of ESD and fast transients. For continuous overvoltage events this is not a clamp — it is a one-shot protector.
AEC-Q101 and the automotive bill of materials
AEC-Q101 qualification is the baseline for any semiconductor used in a Tier-1 automotive module — it means the part passed the stress tests for temperature cycling, high-temperature reverse bias, and humidity.
Package and footprint — SMC (DO-214AB)
Housed in the DO-214AB (SMC) package, surface-mount. The SMC body is larger than the SMA/SMB siblings, which is what carries the 1500W rating — the extra copper area and junction size handle the thermal pulse. Footprint is a standard SMC land pattern; no special pad geometry needed beyond the datasheet recommendation.