33 V zener with ±1% tolerance — still in active production
The 1N6012D is a 33 V zener diode from Microchip Technology with a ±1% tolerance, rated for 500 mW continuous power dissipation in the DO-35 axial package. This is an active-production part — no end-of-life or NRND notice to track, so it remains a standard BOM line for voltage regulation, clamping, and reference circuits.
Wide temperature range and low leakage
Reverse leakage is specified at 100 nA maximum at 25 V reverse voltage — 8 V below the zener knee — so the diode draws negligible current in the off state, important for battery-powered bias networks and precision voltage references. Maximum zener impedance (Zzt) is 88 Ohms at the test current. This impedance affects the regulation slope: at lower bias currents the dynamic resistance rises, so the output voltage shifts more with current variation. For the tightest regulation, bias the diode at or above the manufacturer's test current.
DO-35 axial package — through-hole board integration
The DO-204AH (DO-35) axial leaded package is the standard through-hole footprint for 500 mW zeners. The glass body and tin-plated copper leads handle wave soldering and manual rework without issue. Bulk packaging means the diodes ship loose in a bag or tube — no tape-and-reel, so pick-and-place requires hand insertion or a tube feeder.