Zener transient suppressor – 500W, hermetic SQ-MELF
It provides a single unidirectional channel with a reverse standoff voltage of 40.3V and a clamping voltage of 63.5V at the peak pulse current of 45A (8/20µs).
For a 40.3V standoff rail, the 63.5V clamp voltage ensures the downstream circuitry sees less than 64V during a surge — critical for protecting 48V bus or 36V nominal supply lines in military or industrial gear. Compare this to the expected surge current from a lightning strike or inductive load dump; if the surge exceeds 45A, you need a higher-rated TVS or a parallel clamp.
The base product number is 1N6467; the 'US' suffix denotes the SQ-MELF surface-mount package variant. The through-hole equivalent (1N6467) shares the same die but differs in package — the SQ-MELF version is preferred for automated assembly and hermetic sealing.
SQ-MELF package – rework and assembly considerations
The SQ-MELF (B, SQ-MELF) is a hermetic, surface-mount package with metallized end caps. It reflows well with standard solder profiles, but the ceramic body has higher thermal mass than a plastic SMD — preheat the board to 150°C before hot-air rework to avoid thermal shock. The package is polarity-sensitive; the cathode end is marked with a band.