1N4991

Single Zener Diodes Overview

The Microchip Technology 1N4991 is a military-qualified, voidless hermetically sealed 5-watt glass Zener diode. It provides a nominal voltage of 240 V with a standard tolerance of ±5%. The device operates within a junction temperature range of -65°C to +175°C and features an axial lead configuration. Electrical characteristics include a maximum reverse leakage current of 2 µA at 20 V, a maximum Zener impedance of 650 Ohms at the test current, and a continuous current rating of 19.8 mA.

Single Zener Diodes Feature Summary

• Hermetically sealed construction using voidless hard glass with tungsten slugs for extreme robustness
• Military qualification compliant with MIL-PRF-19500/356 standards
• Internal metallurgical bonds ensuring high reliability in critical applications
• Triple-layer passivation providing inherent radiation hardness

Single Zener Diodes Applications

• High-reliability aerospace systems where failure cannot be tolerated
• Military-grade power supply regulation circuits
• Harsh environment electronic protection requiring radiation hardness

Single Zener Diodes Procurement Notes

Verify that the component meets the specific military qualification requirements of MIL-PRF-19500/356. Confirm the package type matches the required axial lead specifications. Ensure the ordering suffix corresponds to the desired voltage tolerance level. Validate compliance with environmental regulations applicable to your region before finalizing procurement.

Single Zener Diodes Selection Notes

Select this component when a high-power 5-watt Zener regulator is required for demanding environments. The 240 V rating suits high-voltage reference applications. Consider the wide operating temperature range suitable for extreme conditions. Verify that the axial lead form factor fits the mechanical constraints of the target assembly.

Single Zener Diodes Part Context

This part belongs to the industry-recognized 1N4954 through 1N4996 series of 5-watt Zener Voltage Regulators. These components are designed for applications requiring high reliability and robust performance under severe electrical or environmental stress.

Single Zener Diodes Replacement Considerations

Surface-mount equivalents are available in square end-cap MELF configurations with the 'US' suffix (e.g., 1N4991US). Other manufacturers may offer similar 5-watt axial Zener diodes, but verification of hermetic sealing and military qualification is necessary.