Peak pulse power and clamping — what the 400W rating means for the BOM
The SMAJ10A-13-F: At that pulse condition the clamping voltage is 17V max at a peak pulse current of 23.5A, so a 10V nominal rail sees the TVS clamp a transient to 17V before the protected IC's abs-max is reached.
Breakdown and standoff — the protection window
Reverse standoff voltage is 10V; the device starts conducting at a minimum breakdown of 11.1V. That 1.1V guard band keeps the TVS out of conduction under normal 10V rail ripple while still clamping before the downstream part sees damaging overvoltage. No power-line protection rating (Power Line Protection = No) — this part is designed for signal or low-power DC rail transients, not AC mains or high-energy surge events where a higher-energy MOV or gas tube would be specified.
Package and temperature — board-fit and environment
Housed in DO-214AC (SMA), the supplier device package is SMA (the same footprint).