3.6 V Zener in a hermetic MELF
The 1N4729AUR/TR is a 3.6 V Zener diode in a DO-213AB MELF (glass) package, rated for 1 W continuous power dissipation. With ±5% tolerance on the Zener voltage, it is a standard-regulation part — tight enough for rail clamping or simple shunt regulation, not a precision reference. The 10 Ω maximum impedance (Zzt) means the regulation slope is moderate; at the test current, the output voltage shifts about 10 mV per mA of load change.
Surface-mount fit and handling
The DO-213AB MELF is a cylindrical, end-capped package — it reflows like a standard SMD but rolls if the paste is uneven. On the board, the metallized ends are the anode and cathode; orientation is marked by a band on the cathode end. The package footprint matches a standard MELF-LL41 land pattern, and the glass body handles standard reflow profiles without moisture sensitivity (MSL 1).