7.5 V Zener, 1 W — the thermal budget in a DO-41 body
The 1N4737PE3/TR8 is a 7.5 V Zener diode rated for 1 W continuous power dissipation in the DO-204AL (DO-41) axial-lead package. The 7.5 V nominal is the regulation knee — below that the diode blocks; above it the avalanche breakdown clamps the voltage to within ±10% of the nominal value, making it a straightforward shunt regulator or reference element for low-power rails. The 4 Ω maximum Zener impedance (Zzt) at the test current means the regulation voltage shifts by about 40 mV per mA of load change through the knee — a tighter hold than a higher-impedance Zener, which matters if this diode is the only reference in a 5 V-to-3.3 V regulator feedback divider.
DO-41 axial — board-mounting and thermal path
The DO-204AL (DO-41) body with axial leads is a through-hole package that relies on the lead length and copper pad area for heat sinking. At 1 W dissipation the junction-to-ambient thermal resistance is typically 100–150 °C/W depending on lead length and board copper; in free air with 1/2-inch leads the junction sits about 100 °C above ambient at full rated power. The Tape & Reel (TR) packaging option (the /TR suffix) means the diode ships on a reel for automated insertion — axial components on tape are fed through a radial-lead forming machine or a vibratory bowl feeder, not a standard SMD pick-and-place. Confirm the feeder compatibility before committing the line.
Active lifecycle — sourcing posture
Microchip Technology lists this part as Active.