1N4964US

Overview

The Microchip Technology 1N4964US is a surface mount Zener voltage regulator with an 18 V nominal breakdown voltage and ±5% tolerance. It dissipates 5 W at a case temperature of 140°C, derating linearly to zero at 175°C. The device operates within a junction temperature range of -65°C to +175°C. Electrical characteristics include a test current of 65 mA, maximum reverse leakage of 5 µA at 13.7 V, dynamic impedance of 4 Ω at test current, and a temperature coefficient of 0.085 %/°C.

Feature Summary

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

Applications

• High-reliability aerospace and defense circuits
• Critical power supply voltage regulation
• Harsh environment electronic systems

Procurement Notes

Verify the specific revision level and manufacturing origin against the latest official datasheet before procurement. Confirm that the ordering suffix matches the required package type and tolerance specifications. Ensure compliance with relevant military qualification requirements if applicable to the design. Check for any recent packaging or assembly process changes documented in product change notices.

Selection Notes

Select this component when a hermetically sealed surface mount Zener diode is required for critical applications. The 5 W power rating supports substantial current handling in compact packages. Verify thermal management capabilities to maintain junction temperatures within the specified operating range under all expected load conditions.

Part Context

This part belongs to the 1N4954US through 1N4996US series of surface mount Zener regulators. These devices share identical mechanical and electrical construction profiles, differing primarily in their nominal Zener voltage ratings. The series offers extensive voltage selection from 3.3 V to 390 V while maintaining consistent package dimensions and thermal characteristics.

Replacement Considerations

Axial-leaded equivalents are available by removing the US suffix, such as the 1N4964. Other manufacturers produce similar 5 W glass Zener diodes, but direct substitution requires verification of hermetic sealing, metallurgical bond quality, and radiation hardness specifications.