68 V Zener — the regulation anchor
The 1N6020D: 68 V nominal Zener voltage with ±1% tolerance means the breakdown knee is tight enough to serve as a low-power voltage reference or a shunt regulator in a 48 V rail clamp circuit. The 240 Ohms maximum Zener impedance (Zzt) at the test current tells you how much the regulation point shifts with current — lower is better for reference duty, and this figure is typical for a 500 mW part at this voltage. Rated for 500 mW continuous power dissipation in free air. Reverse leakage is specified at 100 nA maximum when 52 V is applied across the junction — that is 16 V below the Zener voltage, confirming the diode stays well into the blocking region before breakdown.
DO-35 glass package — board-fit note
Supplied in DO-204AH (DO-35) axial-lead glass package, through-hole mount. The glass body is hermetic, which matters for humidity-prone or high-reliability environments where a molded epoxy package might absorb moisture over time. Shipped in Bulk — no tape-and-reel, so it is suited for hand-insertion or low-volume assembly rather than automated pick-and-place.