What this TVS protects and where it lives
1500 W peak pulse — sizing the protection margin
For a 70 V rail, the clamping voltage of 146 V means the device will hold the line during a 69 A peak pulse current event (8/20 µs waveform). That margin matters when protecting sensitive ECUs or sensor modules from load-dump spikes that can exceed 100 V.
The base product number SM15T82 covers the unidirectional and bidirectional variants in the same SMC footprint, so a board designed for the SM15T82CAY can also accept the SM15T82A (unidirectional) if the circuit later requires polarity-specific clamping.
DO-214AB SMC — footprint and assembly
No power line protection is built in — this is a transient suppressor, not a regulator — so the design must still include appropriate input filtering and overcurrent protection upstream.