The SM30T23AY is a 3000W (3kW) automotive-grade Zener TVS diode from STMicroelectronics, designed to clamp transients on 20V rails. Its single unidirectional channel handles a peak pulse current of 92.6A under the standard 10/1000µs waveform, clamping at 32.4V maximum. This is the part you spec for load-dump or ISO 7637-2 pulse protection in vehicle electronics — the 3kW rating gives enough headroom to absorb a 24V truck jump-start without letting the downstream rail see more than 32.4V.
AEC-Q101 and the full temperature range
AEC-Q101 qualification is the gating factor for any automotive Tier-1 or under-hood placement. For a 24V truck ECU or a 12V passenger-car ABS module, this part stays within its SOA across the full ambient range without derating the pulse power.
For the full 92.6A peak, the datasheet recommends a minimum pad size of about 80 mm² copper on each side of the board to keep the junction temperature rise within limits.