36 V regulation in a DO-213AA footprint
The 1N6013UR-1/TR is a 36 V zener diode from Microchip Technology, rated for 500 mW continuous power dissipation. The DO-213AA package is a small, surface-mount MELF-style body — the metalized ends reflow directly to the PCB pads, so the footprint is just two rectangular lands. No through-hole lead to bend, no axial body to stand off; it sits flush on the board and the solder joint is the mechanical anchor. At the high end, the 500 mW power limit must be derated per the junction-to-ambient thermal resistance of the DO-213AA body — in still air at 25°C ambient, the full 500 mW is available; above that, the allowable dissipation drops linearly. A practical rule: if the board sees 125°C ambient, budget roughly 60% of the rated power, or about 300 mW, before the junction hits 175°C.