Transient suppression for legacy 77.8V rails
The 1.5KE91A-T: With a breakdown voltage range starting at 86.5V minimum, the diode remains transparent during normal operation and only conducts when the transient exceeds that threshold. The 12A peak pulse current rating confirms the energy-handling capacity for moderate surge conditions.
Obsolete — sourcing through independent channels
Diodes Incorporated has marked the 1.5KE91A-T as Obsolete. No official successor part number is recorded on this line. For designs that cannot tolerate a board spin, the DO-201AA axial footprint is a standard industry package, so a parametric equivalent from another manufacturer (matching 1500W, 77.8V standoff, and unidirectional polarity) can be sourced as a drop-in replacement with appropriate qualification review.
Environmental and mounting considerations
The DO-201AA (DO-27) axial-lead package mounts through-hole, suitable for point-to-point wiring or PCB layouts with 0.100-inch pitch. Tape & Reel packaging supports automated insertion for volume assembly.