Protection window and breakdown tolerance
The 1.5SMC30AHM3/I: The breakdown voltage range is 28.5 V minimum, with the reverse standoff set at 25.6 V — so the TVS stays off during normal 24 V operation and begins conducting when the rail exceeds the breakdown threshold. With a clamping voltage of 41.4 V at the 36.2 A peak pulse current, this part provides a protection window of roughly 16 V between the 24 V nominal rail and the clamped surge — enough margin for most 40 V-rated automotive loads on a 24 V battery system.