The SMCJ45CA-13: The 45 V reverse standoff voltage means this TVS starts conducting only when the line exceeds the normal operating rail — a 48 V bus or a 24 V system with transients stays below the leakage threshold until the surge arrives.
Bidirectional — one part covers both polarities
A single bidirectional channel clamps positive and negative transients symmetrically — the 50 V minimum breakdown voltage and 72.7 V maximum clamping apply in both directions, so you protect a differential pair or an AC-coupled signal line with one component instead of two back-to-back Zeners. The DO-214AB SMC package footprint is shared across the SMCJ family — the same land pattern serves the 5 V through 170 V standoff variants, so a BOM change for a different rail voltage does not require a board spin.
Active production — no last-time-buy pressure
The -55°C to +150°C junction temperature range covers the full industrial temperature envelope — a base-station power supply or a motor-drive control board that sees 85°C ambient still has 65°C of margin before the die reaches its rated limit.