1500W peak pulse — the transient survival ceiling
The 1.5KE43C: The 62.27 V maximum clamping voltage at 25.6 A peak pulse current (10/1000 µs waveform) defines the voltage the downstream circuitry must survive — anything above that and the protected device sees the clamp ceiling, not the transient peak.
DO-201 axial — a through-hole standard for board-level protection
Housed in the DO-201AA / DO-27 axial package, the 1.5KE43C is a through-hole device that mounts with a single drilled hole and solder joint per lead. The axial lead form factor is common in power-entry protection stages — the leads carry the surge current into the die with minimal added inductance compared to a surface-mount part.
Obsolete — sourced through distribution, not the factory
Littelfuse lists the 1.5KE43C as obsolete. For a BOM that already carries this part number, the procurement path is straightforward: submit the quantity and target lead time, and the distributor confirms lot traceability and manufacturer warranty from the available surplus or last-time-buy inventory. No design-in for new builds — the 1.5KE series has been superseded by newer TVS families with higher surge ratings or smaller packages.