The 1.5KE56A-G: The 77 V clamping voltage at 19.48 A peak pulse current means a 47.8 V reverse standoff rail gets clipped hard before the transient reaches downstream silicon — a 24 V or 48 V DC bus protected with this part sees the spike folded to a safe level for most downstream regulators and capacitors.
Breakdown window and temperature range
Minimum breakdown voltage is 53.2 V, so the part starts conducting in avalanche at roughly that threshold. The reverse standoff (working voltage) is 47.8 V — the rail can sit at that level continuously without leakage becoming a problem.
Supplied in a DO-201AA (DO-27) axial-lead package, through-hole mount. The DO-201 footprint is a standard axial diode hole pattern — two 1.0 mm diameter holes on 0.375-inch lead spacing. The tape-and-box packaging (TB) suits hand-insertion or selective-wave solder; no moisture sensitivity level concern for a hermetic glass-passivated die in an axial body.
Active production — no lifecycle worry
Comchip Technology lists the 1.5KE56A-G as Active.