Peak pulse power and clamping headroom — the TVS selection axis
The 1.5SMC62CA-M3/9AT: A rail-clamping margin of roughly 32 V (85 V clamping minus 53 V standoff) gives the downstream load headroom before the diode takes the event. The 17.6 A peak pulse current confirms the diode handles the surge current without going into thermal runaway during a single event.
The bidirectional polarity means this diode clamps both polarities of the transient — the circuit sees symmetric protection without needing two unidirectional devices back-to-back. The DO-214AB (SMC) package is the standard surface-mount outline for 1.5–3 kW TVS parts; the land pattern is widely supported, and standard stencil apertures apply for paste-in-print assembly. Tape-and-reel packaging is the variant to specify for automated pick-and-place runs — confirm that your contract manufacturer stocks a reel feeder for the SMC reel width before releasing the BOM line.