Transient protection envelope for a 48 V rail
The 1.5KE56A-HF: Its 47.8 V reverse standoff voltage sits below the rail, so it stays out of circuit during normal operation, while the minimum breakdown voltage of 53.2 V defines the trigger point where it starts conducting.
What the 1500 W rating means for the BOM
That clamping voltage is the ceiling the downstream circuitry sees — if the DC-DC converter or load switch on the 48 V rail has an absolute maximum below 77 V, this TVS will not protect it. The 1500 W rating is a peak number; the steady-state power dissipation is negligible because the device only conducts during the transient event.
Supplied in a DO-201AA axial-lead package, also known as DO-27, with the die housed in the DO-201 supplier package. The through-hole mounting requires a drilled hole in the PCB — the axial leads are bent and inserted, then soldered on the opposite side. The 1.5KE-HF series is shipped in Tape & Box format, which is the standard reel-less packaging for axial diodes in production runs.
The junction temperature range spans -55°C to 150°C, covering industrial and outdoor telecom environments where the ambient may reach 85°C and the junction sees additional self-heating during the surge event. The 150°C ceiling is the absolute maximum junction temperature — derate the peak pulse power above 25°C per the datasheet curve. The part carries no power line protection rating, so it is intended for signal or low-voltage DC bus protection, not AC mains.
Active production and sourcing posture
Comchip Technology lists the 1.5KE56A-HF as Active, meaning the manufacturer continues to produce it.