It is a unidirectional Zener-type device rated for a reverse standoff voltage of 30.8V and a minimum breakdown voltage of 34.2V, clamping surges to a maximum of 64.3V at the rated peak pulse current. The SM15T36AY is intended for overvoltage protection on 24V or 28V automotive power buses, ECU input lines, and similar DC rails where a single TVS must absorb load-dump or inductive-kick energy without failing short.
1500W peak pulse power — what it buys you
The 1500W peak pulse power rating (10/1000µs waveform) tells you this part can absorb a substantial single-pulse surge — enough to handle the ISO 7637-2 pulse 5a load dump on a 24V nominal rail without external crowbar circuitry. The peak pulse current capability of 156A (8/20µs waveform) aligns with the higher-energy pulses typical in automotive transient testing. For a 30.8V standoff part, the clamping voltage of 64.3V at peak current means the downstream circuitry sees less than 65V even during a severe event, which is within the absolute-maximum rating of many 60V-rated automotive ICs. The 34.2V minimum breakdown voltage gives a guard band against the 30.8V standoff, so the part stays off the line under normal operating conditions and only conducts when a surge exceeds the threshold.
The DO-214AB SMC package has a standard solder pad layout; no special thermal management is needed for the peak power rating because the surge duration is short enough that the junction temperature rise stays within the 150°C limit. The part is RoHS compliant per the TRANSIL series listing.