16V rail Zener clamp in a DO-214AC footprint
Its breakdown voltage is guaranteed at 17.8V minimum, so the device stays off during normal operation and only conducts when the rail exceeds that threshold.
Breakdown and clamping — the protection window
The reverse standoff voltage is 16V, meaning the TVS draws negligible leakage below that rail level. The minimum breakdown of 17.8V gives a 1.8V margin above the standoff — wide enough to avoid false triggering from ripple or noise on a 16V bus, but tight enough to limit overvoltage stress. The 26V clamping at 19.2A peak pulse defines the worst-case voltage the protected load sees; for a 16V-rated IC, that 26V clamp must stay within the IC's absolute-maximum input rating.
Microchip lists the SMAJ16AE3/TR13 as Active.