DO-214AB footprint, 1500 W clamping
The 1.5SMC510AHE3_A/H: The 434 V standoff means this diode sits across a nominal 400 V bus without conducting leakage, then clamps a transient to 698 V — a margin that protects downstream semiconductors rated for at least 700 V. The single unidirectional channel handles one polarity; for AC lines you would need two devices back-to-back.
Automotive qualification and temperature grade
The TransZorb® construction delivers the 1500 W pulse rating with a fast response time typical of Zener avalanche diodes. Vishay lists this part as Obsolete. For new designs or BOM positions that need an active AEC-Q101 TVS in the same voltage class, a parametric search on 434 V standoff and DO-214AB package will yield current-generation alternatives from Vishay or competitors — expect a board-spin if the footprint or electrical characteristics shift.
Sourcing reality for an obsolete automotive TVS
No pin-compatible direct replacement from Vishay is documented. If your board is already in production with the 1.5SMC510AHE3_A/H, the safest path is to secure a last-time buy of the remaining surplus inventory. For a new layout, a current-production TVS with the same DO-214AB footprint and 434 V standoff avoids a respin.