Obsolete 1500W bidirectional Zener TVS — what the ratings mean for fit
The 1.5KE400CAE3/TR13: The 324V reverse standoff voltage means the TVS draws negligible leakage below that DC rail — it sits across a 300V bus without loading it — and clamps transients at 548V maximum, protecting downstream silicon rated for at least that breakdown margin. The single bidirectional channel in a DO-201AA axial package handles both polarities in one device, saving board space over two unidirectional TVS diodes back-to-back. The -65°C to 150°C junction-temperature range covers military/aerospace thermal cycling without derating at the cold end.
Lifecycle reality — obsolete, sourced through independent channels
Microsemi has marked this part obsolete. No official successor order code is recorded, so the replacement path is either a pin-compatible TVS from another manufacturer with matching 324V standoff and 1500W rating, or a board-level change if the footprint differs.