1500W bidirectional transient suppressor for 77.8V rails
The 1.5KE91CA R0G: At the 12.6A peak pulse current the clamping voltage is held to 125V maximum, which keeps downstream semiconductors within their 150V to 200V breakdown margin in a typical 48V to 72V bus system.
Breakdown and standoff — the margin that matters
Reverse standoff voltage is 77.8V typical — the diode draws negligible leakage below this level, so it sits across a 48V or 60V rail without loading it. Breakdown triggers at 86.5V minimum, giving a ~9V window between normal operation and the clamping event. Because it is a bidirectional device (single channel), one part protects both polarities on an AC signal line or a floating DC bus. For unipolar rails a single unidirectional TVS would suffice, but the bidirectional variant simplifies BOM management when polarity could reverse during fault conditions.
175°C junction — continuous operation in hot environments
The wide temperature range also means derating for high ambient is less aggressive than with 150°C-rated parts. The DO-201AA (DO-27) axial package is through-hole, requiring a drilled hole and wave solder — not a surface-mount reflow step. For high-volume SMT lines this adds a manual or selective-solder operation, but for prototyping or low-to-mid volume builds the axial lead form is easy to hand-solder and inspect.
Taiwan Semiconductor lists the 1.5KE91CA R0G as Active, meaning the manufacturer is still producing it without a last-time-buy or discontinuation notice. No successor part is recorded, so the same order code continues to ship. Reel quantity is consistent with the DO-201 format; confirm the exact reel count with your distributor at RFQ time.