What the 1.5 kW rating means on the bench
The SMCJ85CA-13-F: That 1.5 kW rating is the energy it can absorb in a single transient without failing short — on a 85 V rail, the clamping voltage of 137 V at 10.4 A peak pulse current tells you the protection threshold. When a surge hits, the TVS fires at its breakdown voltage (94.4 V minimum) and clamps the spike to 137 V, shunting the 10.4 A away from the downstream circuitry.
Package and board-fit reality
Housed in a DO-214AB (SMC) surface-mount package, the SMCJ85CA-13-F is a standard footprint for 1.5 kW TVS diodes. The SMC package is larger than the SMA/SMB siblings — the extra body area and copper pad dissipate the pulse heat. It is bidirectional in a single package, so one part clamps both polarities on a signal line or DC rail.