1.5KE400ARL — 1500 W unidirectional TVS for 342 V DC rail protection
The STMicroelectronics 1.5KE400ARL is a unidirectional Zener transient-voltage-suppression (TVS) diode from the 1.5KE / TRANSIL™ series, rated for 1500 W peak pulse power (1.5 kW) over the standard 10/1000 µs waveform. It is designed to clamp overvoltage transients on DC power rails, industrial bus lines, and general-purpose protection circuits where the operating voltage stays at or below 342 V (reverse standoff, typical).
Clamping performance and surge current handling
With a minimum breakdown voltage of 380 V and a maximum clamping voltage of 706 V at the rated peak pulse current of 14 A (8/20 µs waveform), this part provides a defined crowbar-like clamp for surges originating from switching transients, inductive kickback, or lightning-induced events on 342 V nominal rails. The 390 pF typical capacitance at 1 MHz is moderate — acceptable for DC and low-frequency AC lines, but worth checking if the protected line carries high-speed data or switching edges where added capacitive loading could round off transitions.
For BOM planning, this removes the immediate obsolescence risk that often drives emergency last-time-buy exercises on older axial-leaded TVS parts. That said, the 1.5KE series is a mature product line — procurement should still monitor ST's PCN notifications periodically, as the active status does not guarantee indefinite production.