91 V zener — what the ratings mean on the board
The 1N6023C is a 91 V zener diode in a DO-35 axial-lead package, rated for 500 mW continuous power dissipation. That 91 V breakdown at ±2% tolerance means it clamps a rail or provides a reference voltage within about 1.8 V of the nominal — tight enough for most bias and protection circuits without an external trim. Reverse leakage is specified at 100 nA maximum when the applied voltage is 69 V, well below the breakdown knee. For a high-impedance node — say, the feedback divider on a switching regulator — that leakage current won't shift the set point by more than a few millivolts. A board that sees -55°C cold soak or 150°C junction temperature in a sealed enclosure stays within the device's rated envelope.
Package and through-hole fit
The DO-35 (DO-204AH) axial-lead package is a standard 0.020-inch diameter lead, 0.160-inch body length. It fits the same 0.100-inch pitch through-hole footprint as the 1N4744A or 1N5369B family — no board layout change if you are swapping into an existing position. Supplied in bulk tube, not tape-and-reel. For hand-assembly or low-volume production runs, the tube is the expected format; for automated insertion, request the reel-pack variant if one exists under the base number 1N6023.