Clamping voltage and peak pulse current — the real protection ceiling
The 1.5KE43A/B: At that power level the clamping voltage reaches 59.3V at a peak pulse current of 25.6A, which sets the maximum transient the protected line sees before the diode conducts. The reverse standoff voltage is 36.8V, so the diode stays high-impedance on a nominal 36V rail. Breakdown occurs between 40.9V and the clamping limit — the device starts conducting just above the rail voltage and holds the clamp below 60V across the full surge current.
Package, mounting, and board-fit note
Supplied in a DO-201AA (DO-27) axial leaded package, through-hole mount. The DO-201 body is the same footprint used across the 1.5KE family, so a single board layout serves multiple voltage variants. The axial leads require a hole diameter of roughly 1.0 mm to 1.2 mm on the PCB — standard for a 1500W TVS.
The 1.5KE series is widely second-sourced, but no official cross-reference is recorded here — verify the clamping voltage and standoff match your rail before substituting.