78V standoff, 126V clamp — the protection window for 48V and 60V rails
The SMBJ78CA-13 is a bidirectional Zener-type TVS diode from the SMBJ series, designed to clamp transients on DC power buses. With a 78V reverse standoff voltage and a minimum breakdown of 86.7V, it sits above nominal 48V and 60V rails without conducting during normal operation. For shorter transients (8/20µs, common in ESD or lightning), the device can absorb significantly more peak power before the junction temperature limit is reached.
DO-214AA SMB — rework-friendly footprint
Housed in the DO-214AA (SMB) package, the SMBJ78CA-13 is a surface-mount part with a body that handles a hot-air rework cycle without the pad lifting issues of smaller SOD packages. The SMB footprint is large enough to hand-solder with a fine tip if needed, and the cathode band (or bidirectional marking) is clearly moulded — no guessing pin 1 orientation on a bidirectional part. The wide range means the leakage current at 78V standoff stays manageable even at high ambient — a key factor when the TVS sits on a hot PCB near a power supply.
Active production, sourced per RFQ
The base product number is SMBJ78, meaning the unidirectional variant shares the same breakdown and clamping specs but with a single-direction polarity. For bidirectional protection on a single line, the CA suffix is the correct choice — no need for two diodes back-to-back.