What the 1500 W peak pulse rating means for your rail
The 1.5KE15A-E3/51: That 1500 W figure defines the energy it can clamp without failing — at the rated 70.8 A peak pulse current, the clamping voltage holds at 21.2 V max. The reverse standoff voltage is 12.8 V, meaning the diode stays off below that line voltage and only starts conducting when a transient pushes past the 14.3 V minimum breakdown threshold. For a 12 V rail, this gives enough margin to avoid nuisance clamping from normal ripple while catching surges before they reach the load.
Lifecycle reality — Last Buy, not an active line item
Vishay lists this part as Last Buy. That means the manufacturer has announced end-of-life and the final production window is closing — new orders are accepted only for the remaining build allocation. For a BOM that already carries this part, the Last Buy status means procurement should lock in the lifetime buy quantity now. For new designs, a functionally equivalent 1500 W unidirectional TVS in a DO-201 package with the same 12.8 V standoff and 21.2 V clamp can be sourced — but the pinout and footprint are standard axial, so any DO-201 TVS with matching parametrics fits without a board spin.
Temperature range and package — board-fit constraints
The DO-201AA (DO-27) axial package is through-hole — the leads are 0.96 mm diameter typical, fitting a 1.0 mm plated-through hole on a standard 2.54 mm pitch. The bulk packaging means no reel or tape; parts ship loose in tubes or bags.