Surge rating and protection window
The 1.5SMC12CA-E3/9AT: The 89.8 A peak pulse current at that same waveform (cite:) tells you the diode can absorb a high-energy surge from a lightning-induced transient or inductive load dump without failing short. A 12 V nominal rail has margin below the standoff, so the diode stays off until the transient pushes above 11.4 V.
Package, footprint, and temperature range
Housed in DO-214AB (SMC) — the same footprint as the SMCJ series. The large copper tab on the bottom side conducts heat into the PCB pad; the junction temperature range spans -65°C to 150°C, so it survives soldering reflow and high-ambient enclosures without derating the surge rating at the hot end. Bidirectional single-channel construction — one device clamps both polarities, which matters for AC signal lines or DC rails where reverse-voltage events are possible. No power line protection rating (per spec), meaning it is intended for signal or low-voltage DC bus protection, not mains AC input.