1500 W peak pulse — the clamping ceiling
The 1.5SMC43CA-M3/57T: That 1.5 kW ceiling means it clamps a 25.3 A surge to 59.3 V max — the voltage across the protected rail never exceeds that during the pulse. Breakdown triggers at 40.9 V min — the diode stays high-impedance below that threshold.
DO-214AB (SMC) surface-mount package, also marked as SMCJ. The footprint is standard — reflow profile follows the solder-paste datasheet for the lead-free alloy. Single bidirectional channel — one device replaces two back-to-back unidirectional diodes on a bipolar rail, saving PCB area and bill-of-materials line count.