1N4479US/TR

Single Zener Diodes Overview

The Microchip Technology 1N4479US/TR is a surface mount Zener voltage regulator with a nominal breakdown voltage of 39V. It operates within a junction temperature range of -65°C to +175°C and dissipates up to 1.5W at 25°C ambient. The device features a maximum dynamic impedance of 30 Ohms at the test current of 6.5mA, with a maximum reverse leakage current of 0.05µA at 31.2V. It utilizes an A (D-5A) MELF package and is qualified per MIL-PRF-19500/406.

Single Zener Diodes Feature Summary

• Hermetically sealed void-less glass construction using internal metallurgical bonds for robust reliability.
• Military qualification available under JAN, JANTX, JANTXV, and JANS levels per MIL-PRF-19500/406.
• Inherently radiation hard and non-sensitive to electrostatic discharge.

Single Zener Diodes Applications

• High-reliability applications where failure cannot be tolerated
• Voltage regulation over broad operating current and temperature ranges
• Radiation-hardened circuit designs

Single Zener Diodes Procurement Notes

Verify the specific reliability level suffix required for the application, as the base part number covers multiple qualification grades including JAN, JANTX, JANTXV, and JANS. Confirm RoHS compliance status if applicable, noting that compliant versions are commercial grade only. Ensure the tape and reel packaging meets EIA-481-B standards before ordering.

Single Zener Diodes Selection Notes

Select this component for surface mount implementations requiring high thermal stability and hermetic sealing. The 1.5W power rating supports substantial current handling in compact packages. Consider the 39V nominal voltage and 30 Ohm impedance characteristics against circuit requirements. Verify that the D-5A MELF footprint aligns with the PCB layout constraints.

Single Zener Diodes Part Context

This device belongs to the 1N4460US through 1N4496US series of voidless hermetically sealed surface mount Zener diodes. These regulators are designed as surface mount equivalents to popular JEDEC registered axial-lead series. The series offers extensive voltage selections from 3.3V to 200V with standard 5% tolerance.

Single Zener Diodes Replacement Considerations

Direct replacements must match the 1N4479US electrical specifications and D-5A MELF package. Equivalent parts should maintain the 39V Zener voltage and 1.5W power dissipation rating. Verify that any substitute also meets MIL-PRF-19500/406 qualifications if military-grade reliability is required.

Single Zener Diodes FAQ

What is the maximum continuous Zener current for the 1N4479US?

The maximum continuous regulator current (IZM) is 37mA.

How is polarity indicated on the 1N4479US package?

Polarity is indicated by a band on the package, which marks the cathode end.