What the 600W peak pulse rating means for board-level protection
The P6KE91A-T: The 77.8V reverse standoff voltage means it sits across a nominal 75V or 80V bus without conducting in normal operation; the 86.5V minimum breakdown voltage is the point where avalanche conduction starts. When a surge hits, the device clamps at 125V maximum while shunting 4.8A of peak pulse current (10/1000µs waveform). That 125V ceiling is what the downstream circuitry must survive — if the protected rail's absolute maximum rating is below 125V, this part alone won't protect it.
Obsolete — sourcing through independent channels
Diodes Incorporated lists the P6KE91A-T as obsolete. For existing BOM lines that specify this exact part number, supply runs through independent distribution — surplus and new-old-stock inventory held by brokers and secondary-market suppliers.
DO-15 axial package and temperature range
The device comes in a through-hole DO-204AC (DO-15) axial-lead package, supplier device package DO-15. Tape-and-reel packaging suits automated insertion for through-hole assembly lines.