What the 1500 W pulse rating means for your BOM
The 1.5KE440CAHA0G: At that pulse, it clamps at 602 V max while conducting 2.5 A peak current. That 1500 W rating is the energy-handling ceiling for a single transient; if your line sees repetitive surges, derate per the pulse derating curve in the datasheet. The reverse standoff voltage is 376 V, meaning the diode stays high-impedance below that level and only starts conducting when the transient exceeds the 418 V minimum breakdown.
Automotive qualification and temperature envelope
The 175°C Tj max gives headroom above the 150°C typical automotive limit, useful for high-ambient locations near exhaust or turbocharger paths. It handles the thermal cycling of automotive environments without the solder-joint fatigue risk of surface-mount packages under vibration.