The 1.5SMCJ40C clamps at 71.4 V maximum under a 21 A peak pulse (10/1000 µs waveform) — that 1.5 kW rating is the absorbed transient energy the diode can dissipate in a single surge event without degradation, making it the primary figure for specifying protection margin on a 24 V industrial rail. The reverse standoff of 40 V sits below the 44.4 V minimum breakdown, leaving comfortable headroom for a 24 V nominal rail — the device stays off during normal operation and transitions to clamp only when a transient exceeds the breakdown threshold. Rated for junction operation from -50°C to 150°C, the part covers the full industrial temperature band — the upper limit applies to the chip itself under transient thermal conditions, not the ambient around the board.
DO-214AB package and board-level fit
The SMC (DO-214AB) package mounts surface-mount on the PCB — the cathode band marking identifies polarity orientation on the unidirectional device, which matters during reflow profile setup and for any hand-solder touch-up in production. Strip packaging is standard for this SMC variant — confirm the reel quantity and lead-free solderability status against your assembly line's reflow profile, particularly for the 150°C maximum junction rating under surge thermal stress.