1N4491US

Single Zener Diodes Overview

The Microchip Technology 1N4491US is a surface mount Zener voltage regulator with a nominal breakdown voltage of 120 V and a maximum power dissipation of 1.5 W at 25 °C ambient temperature. It features a standard 5% voltage tolerance and operates within a junction and storage temperature range of -65 °C to +175 °C. The device utilizes a hermetically sealed voidless glass package with tungsten slugs, designated as the D-5A MELF form factor. Electrical characteristics include a test current of 2.0 mA, a maximum dynamic impedance of 400 Ohms, and a maximum reverse leakage current of 25 µA.

Single Zener Diodes Feature Summary

• Hermetically sealed voidless glass construction with internal metallurgical bonds for high reliability
• Qualified per MIL-PRF-19500/406 for military-grade applications
• Inherently radiation hard design suitable for harsh environments
• Non-sensitive to electrostatic discharge (ESD) per MIL-STD-750 method 1020

Single Zener Diodes Applications

• High-reliability voltage regulation circuits where failure is not tolerated
• Military and aerospace electronic systems requiring radiation hardness
• Voltage reference applications in extreme temperature environments

Single Zener Diodes Procurement Notes

Verify that the specific ordering suffix matches the required reliability level, such as JAN, JANTX, JANTXV, or JANS, as these denote distinct qualification standards under MIL-PRF-19500/406. Confirm RoHS compliance status if applicable, noting that commercial versions may differ from military grades. Ensure the procurement documentation explicitly references the correct datasheet revision T4-LDS-0183-1 to guarantee alignment with the specified electrical parameters and mechanical dimensions.

Single Zener Diodes Selection Notes

Select this component when a 120 V Zener diode is required in a surface mount D-5A package with 1.5 W power handling capability. Consider the 400 Ohm dynamic impedance and 25 µA leakage current limits against circuit sensitivity requirements. Verify that the operating environment falls within the -65 °C to +175 °C range and that the thermal resistance of 20 °C/W is compatible with the system's heat dissipation strategy.

Single Zener Diodes Part Context

This part belongs to the 1N4460US through 1N4496US series of industry-recognized Zener voltage regulators. These devices serve as surface mount equivalents to popular JEDEC registered axial-lead series, offering a compact alternative while maintaining robust performance. The series provides extensive voltage selections from 3.3 to 200 volts, catering to diverse regulation needs in both commercial and military sectors.

Single Zener Diodes Replacement Considerations

Direct replacements must match the 120 V nominal voltage, 1.5 W power rating, and D-5A MELF package. Equivalent parts should offer comparable dynamic impedance and leakage current specifications. Verify that any substitute maintains the same hermetic sealing and radiation hardness qualifications if used in critical military or aerospace applications.