1N4991US/TR

Single Zener Diodes Overview

The Microchip Technology 1N4991US/TR is a surface mount Zener voltage regulator with a nominal breakdown voltage of 240 V at a test current of 5 mA. It features a maximum dynamic impedance of 650 Ohms and a reverse leakage current of 2 uA at 182 V. The device dissipates 5 Watts at an ambient temperature of 140°C, with a thermal resistance of 7°C/W from junction to end cap. It operates within a temperature range of -65°C to +175°C and has a maximum continuous current of 19.8 mA.

Single Zener Diodes Feature Summary

• Hermetically sealed voidless glass package with internal metallurgical bonds for high reliability
• Military qualified to MIL-PRF-19500/356 standards
• Inherently radiation hard construction
• Non-sensitive to electrostatic discharge

Single Zener Diodes Applications

• High-reliability military applications where failure cannot be tolerated
• Voltage regulation in harsh environments requiring wide operating temperatures
• Radiation-hardened electronic systems

Single Zener Diodes Procurement Notes

Verify the specific revision level and manufacturing date code upon receipt to ensure compliance with current quality standards. Confirm that the component matches the exact part number designation, as suffixes may indicate variations in tolerance or packaging. Ensure handling procedures account for the hermetic seal integrity during installation.

Single Zener Diodes Selection Notes

Select this component when a high-voltage, high-power surface mount Zener diode is required for critical systems. Consider the 5W power dissipation capability and the wide temperature range suitable for extreme conditions. Verify that the 240V breakdown voltage aligns with the circuit design requirements and that the package dimensions fit the available board space.

Single Zener Diodes Part Context

This device belongs to the 1N4954US through 1N4996US series of surface mount Zener regulators. These components are designed for robust performance in demanding environments. The series offers various voltage options within a standardized package format, allowing for consistent mechanical integration across different voltage rating requirements in high-reliability designs.

Single Zener Diodes Replacement Considerations

Consult the manufacturer's documentation for direct equivalents or cross-reference lists. Ensure any substitute component meets the same MIL-PRF-19500/356 qualification and hermetic sealing requirements to maintain system reliability and environmental resilience.