Clamping specs and board-fit for a 1500W TVS in DO-214AB
The 1.5SMC39A_R1_00001: It clamps at 53.9V max with a 28A peak pulse current, and the reverse standoff voltage is 33.3V — meaning a 24V or 28V rail sees no leakage until the transient exceeds that threshold.
Why the 33.3V standoff and 53.9V clamp matter for your rail
The 33.3V reverse standoff is the DC operating voltage where leakage is negligible — this part is suited for 24V nominal rails (battery, industrial DC bus) with headroom for steady-state ripple. The 37.1V minimum breakdown voltage means it starts conducting just above the rail, and the 53.9V clamp limits the transient to a level most downstream DC-DC converters with 60V abs-max survive. Power line protection is not claimed, so this is a signal or DC rail TVS, not a mains surge suppressor.