What the clamping spec means for the load
The 1.5SMCJ17A-AQ: Once triggered, it clamps the peak pulse current of 54.3A and holds the clamping voltage at 27.6V maximum, so the downstream semiconductor input or rail sees a defined overvoltage spike rather than an undefined surge. At 1500W peak pulse rating, the part survives single-event transients (ESD, inductive kick, switching noise) well within its thermal limit as long as the event stays within the 10/1000 µs waveform envelope the 54.3A figure is measured under.
1500W peak pulse and the automotive temperature grade
The DO-214AB (SMC) package is the standard pick for 1500W TVS parts because the exposed pad and wider body give better thermal impedance to the board copper than the smaller SMA or SMB outlines.