Transient protection for harsh environments
The single bidirectional channel means one device handles both positive and negative surges, which simplifies the BOM for AC-coupled or bipolar signal lines. Junction temperature range spans -55°C to 175°C, so this part fits avionics, downhole instrumentation, and outdoor telecom cabinets where the ambient can push past 125°C. The SQ-MELF B package is a surface-mount hermetic-style body — the ceramic-to-metal seal keeps moisture out, which matters for long-life deployments in humid or condensing environments.
Clamping voltage and breakdown margin
Reverse standoff voltage is 38.8V typical; breakdown occurs at a minimum of 48.5V. The clamping voltage at peak pulse current is 70.1V max — that 21.6V window between standoff and clamp gives the designer margin to place the TVS after a fuse or series resistor without nuisance triggering on normal line ripple. Peak pulse current capability is 7.1A for the 10/1000µs waveform. The 500W rating is the product of clamp voltage and peak current — a standard metric for comparing TVS diodes across package families. No power line protection is built in, so this device is intended for signal or low-power rail clamping, not mains-side suppression.
Active production — no end-of-life pressure
The base product number 1N6123 covers multiple voltage variants in the same SQ-MELF footprint, so if a different standoff voltage is needed later, the board layout stays the same. Package is — not tape-and-reel — so plan for manual or tube-fed placement. The SQ-MELF B body is a standard surface-mount footprint; the metal end caps are the anode and cathode terminals. Solder profile follows standard SnPb or Pb-free reflow for ceramic packages.