What the 1.5kW pulse rating means on the bench
The 1.5SMC27A-AU_R2_000A1: That 40A peak pulse current (Ipp) at 37.5V clamping tells you the device absorbs a 1.5kJ surge without failing short, which is the failure signature you'd see as a scorch mark on the board if the TVS undersized. Once the clamp fires, it holds the line to 37.5V max — well within the 40V abs-max of most downstream 24V-rated ICs.
Automotive-grade qualification and temperature range
AEC-Q101 qualification means this part passed the full automotive discrete stress battery: high-temperature reverse bias (HTRB), temperature cycling, and ESD robustness per JEDEC JESD22.