1500 W peak pulse, 70.1 V clamp — the transient budget
The 1.5KE51A: The reverse standoff voltage is 43.6 V typical, meaning the diode draws negligible leakage below that rail voltage. Breakdown starts at a minimum of 48.5 V, giving a 4.9 V window between normal operation and the onset of conduction — tight enough for a 48 V bus but with enough margin to avoid nuisance clamping on ripple.
Through-hole axial package, wide temperature range
Housed in a DO-201AA (DO-27) axial leaded package, the 1.5KE51A is a through-hole part — it solders into a 1.1 mm diameter hole on the board and handles the reflow profile of a hand-solder or wave-solder line without issue. The junction temperature range spans -55°C to 175°C, so it survives the thermal cycling of outdoor or engine-bay environments.