15 V regulation at 1 W — the DO-41 workhorse
The Microchip Technology 1N4744AGE3 is a 15 V Zener diode in the standard DO-41 axial-leaded package, rated for 1 W continuous power dissipation. That 1 W ceiling means the device can regulate a 15 V rail at up to roughly 66 mA before the junction temperature climbs above the derating limit — a practical clamp for low-power bias supplies, reference rails, or transient absorption in industrial control boards. The ±5% tolerance on the nominal 15 V Zener voltage gives a regulation window of 14.25 V to 15.75 V at the test current — tight enough for most 15 V logic or analog rails, but not a precision reference. For a 5% part, the real design margin comes from the 14 Ohms maximum Zener impedance; at low bias current the regulation softens, so the load current should stay above a few milliamps to keep the output within the tolerance band.
Temperature range and leakage — what the -65°C to 175°C rating means
In a 125°C ambient environment, the 1 W power rating must be derated per the device's thermal resistance; the DO-41 package in still air typically halves the allowable dissipation above 100°C. The 5 µA maximum reverse leakage at 11.4 V is specified at 25°C — expect leakage to roughly double every 10°C rise, so at 125°C the leakage current approaches 300–400 µA, which may matter for a high-impedance bias node. The forward voltage spec of 1.2 V at 200 mA confirms the diode conducts as a standard rectifier in the forward quadrant — useful if the part is also used as a low-cost clamp in the forward direction, though the 1 W dissipation limit still applies.
It is a current-production catalog item, not a phase-out or NRND line. The Bag packaging indicates loose-tube or bulk shipment — typical for through-hole diodes ordered in moderate quantities. For reel or ammopack requirements, confirm the packaging code with the distributor at RFQ.