What the 1500W peak pulse rating means on the board
The 1.5SMC150A_R1_00001: At the 7.2 A peak pulse current (Ipp) the clamp voltage holds at 207 V max, which means downstream silicon rated for 250 V or better stays inside its safe operating area.
Package and temperature fit
Housed in a DO-214AB (SMC) surface-mount package, the same footprint as the standard SMC diode. The junction temperature range spans -55°C to 150°C, so it handles the hot side of a power supply or an outdoor enclosure without derating at the top end. No power line protection built in — this is a signal or DC rail clamp, not an AC mains suppressor.