What the 400W rating means on the bench
The SMAJ70CA-13-F: When a transient hits, the diode clamps at 113V max (the clamping voltage at 3.5A peak pulse current), shunting the energy away from the downstream silicon. The reverse standoff voltage is 70V, meaning the diode stays off below that rail voltage and only starts conducting when the transient exceeds the minimum breakdown of 77.8V. For a 48V or 60V DC bus, this gives enough margin to avoid nuisance triggering while still catching overvoltages before they reach the load.
Package and placement
Housed in a DO-214AC (SMA) surface-mount package, the SMAJ70CA-13-F shares the same footprint as other SMA-packaged TVS diodes — a standard two-pad layout with the cathode marked by a band. The package is rated for reflow soldering and ships in Tape & Reel (Cut Tape also available), so it feeds straight into a pick-and-place line. No power line protection feature is listed — this is a general-purpose transient suppressor for signal or low-power DC rails, not a primary AC mains protector.
The base product number is SMAJ70, so the -13-F suffix denotes the Tape & Reel packaging variant. If you need a different reel quantity or cut tape, the same die in the same package is orderable under the base number with a different suffix.