1500W automotive-grade TVS — 256 V rail clamp
The Vishay 1.5SMC300AHE3_ALL is a 1500 W peak-pulse TVS Zener diode from the TransZorb® series, qualified to AEC-Q101 for automotive applications. This is the energy it absorbs in a single surge event before the junction temperature exceeds the 150 °C maximum. For shorter pulses (8/20 µs) the peak power capability is higher, but the 10/1000 µs figure is the one to budget against the worst-case transient in the system.
AEC-Q101 and the -65 to 150 °C operating envelope
AEC-Q101 qualification means this part passed the automotive-grade stress tests: high-temperature reverse bias, temperature cycling, and ESD robustness per the JEDEC standard. Production status is active — the part is in current manufacture, not a last-time-buy or NRND item.
DO-214AB SMC — footprint and board-fit note
The copper pad area under the cathode tab sets the thermal resistance — a 600 mm² pad on 2 oz copper drops RθJA to roughly 60 °C/W, which matters when the part absorbs repetitive pulses.