Its 48 V reverse standoff voltage means it sits across the supply without conducting during normal operation, then triggers at a minimum breakdown of 53.3 V to shunt the surge. The clamping voltage peaks at 100 V at the rated 23 A peak pulse current, so the downstream circuitry needs to survive that ceiling. This is a Zener-type TVS, not a steering-diode array; it protects one rail, not multiple signal lines.
Package and footprint — DO-214AC SMA
This is a common footprint shared across the SMAJ family and many other TVS diodes, so the PCB layout is straightforward — two pads, cathode band marked.