Transient protection for 356 V rails
The 1.5KE440C is a bidirectional Zener-type TVS diode from Diotec Semiconductor, designed to clamp transients on DC power rails and signal lines where the normal operating voltage sits at 356 V (the reverse standoff voltage).
Breakdown and clamping profile
Breakdown occurs at a minimum of 396 V, meaning the device starts conducting and absorbing surge energy once the transient exceeds that threshold. Single bidirectional channel — one device clamps both polarities, which simplifies PCB layout on AC or bipolar DC lines compared to back-to-back unidirectional TVS diodes.
Through-hole mounting and thermal envelope
Operating junction temperature spans -50 °C to +175 °C — wide enough for outdoor telecom cabinets, industrial power supplies, and motor-drive DC buses where ambient heat and self-heating from repetitive surges stack.
Sourcing and lifecycle posture
No official second-source or successor cross-reference is recorded — the part is specified as-is for the protection requirement.