What the 1500W rating means on the bench
The 1.5KE350CA R0G is a 1500W bidirectional TVS from the 1.5KE series, built to clamp transients on a 300V DC bus. The breakdown voltage starts at 333V minimum, and the clamping voltage peaks at 482V at the rated pulse current of 3.2A. That 482V ceiling is what the downstream silicon sees — if your DC bus cap or downstream regulator is rated for 500V, this diode holds the transient below its absolute maximum.
This is a single bidirectional channel — one DO-201 package handles positive and negative transients symmetrically. On a floating or bipolar rail you save a diode and a board spin compared to back-to-back unidirectional parts.
Active production — no last-time-buy pressure
Taiwan Semiconductor lists this part as Active. The DO-201AA (DO-27) axial package is through-hole — easy to hand-rework or replace on a prototype board. Pin 1 is the cathode band; the bidirectional marking is symmetrical, so orientation matters only for the banded end on the PCB silkscreen.