The 1.5SMC440AHM3_A/I: This Zener TVS clamps a 376V nominal rail at 602V during a 10/1000µs surge, absorbing 1500W of peak pulse power — enough to shunt an automotive load-dump or telecom lightning transient without the part failing short. Breakdown occurs at 418V minimum, giving a 42V margin above the 376V standoff before the diode starts conducting leakage — this window keeps the rail clean under normal operation while triggering fast when the surge arrives.
Automotive-grade qualification and temperature range
AEC-Q101 qualification means this TVS is screened for automotive reliability — it passes the temperature cycling, high-temperature reverse bias, and ESD stress tests required for under-hood or cabin electronics.
DO-214AB SMC package and board-fit notes
Surface-mount DO-214AB (SMC) package — the same footprint as standard SMC diodes. The copper pad area under the cathode tab sets the thermal resistance; a 1 oz copper pad of at least 30 mm² keeps the junction temperature rise within the derating curve. Tape-and-reel packaging (TR) suits high-volume pick-and-place; the MSL rating is typically Level 1 for these molded packages, so no pre-bake is required before reflow if the shelf life is current. Unidirectional, single-channel — cathode band marks the polarity. The 418V breakdown voltage is tested at 1 mA; the actual clamping voltage at the 2.5A pulse is 602V max, so the PCB layout should keep the trace inductance low to avoid overshoot above the clamp.