Clamping voltage and transient energy rating
The 1.5KE400A is a 1500W (1.5kW) peak pulse power TVS diode from the Littelfuse 1.5KE series, designed to clamp transients on DC power rails or signal lines operating up to 342V continuously. The 342V reverse standoff voltage means the diode draws negligible leakage current below that threshold, making it suitable for 300V or 340V nominal DC buses where the margin to breakdown is about 38V.
Package and board integration
Housed in a DO-201AA (DO-27) axial leaded package, the 1.5KE400A mounts through-hole on the PCB — the body diameter and lead spacing are standard for this power level, and the axial form factor allows either vertical or horizontal mounting depending on board layout constraints. The through-hole package requires a drilled hole and wave-solder process; the DO-201 footprint is shared across the 1.5KE series, so a single PCB land pattern serves the whole family from lower to higher voltage variants.
The wide temperature range means the clamping voltage and leakage current remain within specification across the full military-temperature band — no derating needed for cold starts at -40°C or sustained operation at 150°C junction.