Obsolete — sourcing reality for the 1.5KE91CA-B
This means the manufacturer no longer produces this part, and the only supply channel is independent surplus or broker inventory — no factory orders or last-time-buy windows remain open.
What the 1500W clamping means for your circuit
The 77.8V reverse standoff voltage is the maximum DC or AC peak voltage the protected line can carry without the diode conducting — above that it begins to avalanche. With a breakdown voltage range starting at 86.5V minimum, the 1.5KE91CA-B is sized for 72V to 90V nominal rails where the transient energy stays under 1500W. The single bidirectional channel protects against both positive and negative surges on the same line, eliminating the need for two diodes in anti-series.
Package and board-fit — DO-201 axial leaded
Housed in a DO-201AA / DO-27 axial leaded package, the 1.5KE91CA-B is a through-hole device. The DO-201 body is larger than the common DO-15 or DO-41, sized to handle the 1500W pulse energy without exceeding the package's thermal limits. The axial leads require 0.040-inch diameter holes on a 0.35-inch lead spacing — standard for replacement on legacy PCB layouts. Supplied in Bulk packaging, meaning loose tubes or bags rather than tape-and-reel — this is typical for through-hole power diodes and suits bench-level or low-volume production. No power line protection feature means this is a pure transient suppressor, not a filter or overcurrent device.