1N4955

Overview

The Microchip Technology 1N4955 is a military-qualified, voidless hermetically sealed glass Zener Voltage Regulator diode designed for high-reliability applications. It features a 7.5 V nominal Zener voltage with a standard ±5% tolerance and operates at a test current of 175 mA. The device dissipates up to 5 Watts of power and maintains functionality across an operating temperature range from -65°C to +175°C. Key electrical specifications include a maximum reverse leakage current of 100 µA at 5.7 V, a dynamic impedance of 1.5 Ohms at the test current, and a forward voltage of 1.5 V at 1 A.

Feature Summary

• Military qualified to MIL-PRF-19500/356 standards for critical reliability requirements
• Voidless hermetically sealed glass package with internal metallurgical bonds
• Inherently radiation hard and non-sensitive to electrostatic discharge

Applications

• High-reliability aerospace systems where component failure is not tolerated
• Radiation-hardened electronic circuits
• Voltage regulation in extreme temperature environments

Procurement Notes

Verify that the specific ordering suffix matches the required qualification level (e.g., JAN, JANTX, JANTXV) as these denote distinct screening levels per MIL-PRF-19500/356. Confirm compliance with RoHS directives if applicable, noting that many military variants are exempt. Ensure the procurement documentation explicitly references the correct datasheet revision and includes full traceability records for the metallurgical bond integrity.

Selection Notes

Select this component when a robust 5 Watt axial-lead Zener regulator is required for harsh environments. The 1N4955 provides stable voltage regulation within a broad operating current range. Consider the specific thermal resistance characteristics and derating curves for your application's lead mounting conditions. Verify that the 7.5 V breakdown voltage aligns with the circuit design requirements and that the package dimensions fit the available board space.

Part Context

This part belongs to the industry-recognized 1N4954 through 1N4996 series of 5 Watt Zener Voltage Regulators. These components share a common voidless-glass construction and are widely used in defense and aerospace sectors. The series offers extensive voltage selections ranging from 3.3 to 390 volts, providing designers with standardized options for various high-power regulation needs while maintaining consistent mechanical and environmental performance profiles.

Replacement Considerations

Equivalent parts include JAN1N4955, JANTX1N4955, and JANTXV1N4955. These variants maintain identical electrical parameters but differ in manufacturing screening and qualification levels according to MIL-PRF-19500/356. Surface-mount equivalents are available under the 1N4955US designation.