62 V Zener — the regulation anchor
The 1N6019A is a 62 V Zener diode from Microchip Technology, rated for 500 mW continuous power dissipation in a DO-35 axial-lead package. With a reverse leakage of only 100 nA at 39 V, the diode draws negligible current below the breakdown knee — useful in battery-powered or high-impedance bias networks where every nanoamp counts.
DO-35 axial — board-fit reality
The DO-204AH (DO-35) glass package is a through-hole axial-lead format measuring about 4.5 mm body length with 0.55 mm diameter leads. It mates with standard 0.035-inch diameter plated-through holes on 0.4-inch lead spacing — a footprint shared by countless small-signal diodes, so the board layout is already proven. The 500 mW power limit derates above 25°C — at 175°C the allowable dissipation drops to zero, so keep the junction temperature budget in mind for continuous operation near the limit.