The 1.5SMC100A-E3/57T: That 1500 W rating means it can clamp a transient surge up to 10.9 A without failing — the clamping voltage at that current is 137 V max, so a 24 V or 48 V rail seeing a spike gets held to a safe level before the downstream silicon sees damage.
Standoff voltage and protection window
The reverse standoff voltage is 85.5 V — this is the DC or peak-AC voltage the diode can sit across without conducting in normal operation. Breakdown occurs at a minimum of 95 V, so the protection window starts just above the rail voltage, leaving margin for steady-state ripple. The 137 V max clamping voltage ensures the transient never exceeds that ceiling, protecting downstream components rated for 150 V or less.
DO-214AB (SMC) — hand-solderable and board-friendly
Housed in the DO-214AB (SMC) package, this is a surface-mount part with a standard footprint that's large enough for hand soldering with a fine-tip iron — no hot-air station required. The package is rated for -65°C to 150°C junction temperature, covering everything from outdoor telecom cabinets to under-hood automotive modules. No power line protection feature, so it's a pure transient suppressor, not a crowbar or a filter.