170V standoff, 275V clamp — what the rail sees
The SMBJ170CA-13: With a 170V reverse standoff voltage, this TVS sits across a 170V DC rail without conducting in normal operation. When a transient exceeds the 189V minimum breakdown voltage, the device clamps at 275V maximum while shunting 2.2A of peak pulse current (10/1000 µs waveform). The 275V ceiling is the voltage the protected circuit must survive — if the downstream components are rated below that, the TVS alone won't save them. The single bidirectional channel means one device handles positive and negative transients equally, which simplifies the BOM for AC-coupled or floating signal lines where polarity isn't fixed.
600W peak pulse in DO-214AA — the thermal budget
Surface-mount assembly with the standard SMB footprint keeps reflow compatible with no through-hole step. Available in tape-and-reel for production pick-and-place or cut tape for prototype quantities.