1N4954US

Overview

The Microchip Technology 1N4954US is a surface mount Zener voltage regulator with a nominal breakdown voltage of 6.8 V at a test current of 175 mA. It features a maximum dynamic impedance of 1.0 Ohms and a maximum reverse leakage current of 150 µA at 5.2 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.

Feature Summary

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

Applications

• High-reliability applications where failure cannot be tolerated
• Voltage regulation over broad operating current and temperature ranges
• Harsh environment electronics requiring robust construction

Procurement Notes

Verify the specific revision level and manufacturing origin against the latest official datasheet before procurement. Confirm that the package marking and termination finish match the design requirements, as previous inventory may have differed in end cap material. Ensure compliance with relevant military specifications if required by the application.

Selection Notes

Select this component when a hermetically sealed surface mount Zener diode is required for high-power dissipation up to 5 Watts. Consider the 1N4954US for circuits needing precise voltage reference or protection in extreme temperature environments. Verify that the D-5B package dimensions fit the available board space and that the lead-free status meets project constraints.

Part Context

This part belongs to the 1N4954US through 1N4996US series of surface mount Zener regulators manufactured by Microchip Technology's Scottsdale Division. These devices are industry-recognized for their robust glass construction and are designed to replace traditional axial-leaded equivalents in modern surface mount assemblies while maintaining high reliability standards.

Replacement Considerations

Axial-leaded equivalents such as the JAN1N4954 are available but require different mounting techniques. Surface mount alternatives within the same power rating family include parts like the 1N4955US or 1N4953US, provided the voltage and package compatibility align with the circuit design.