1N4994US/TR

Single Zener Diodes Overview

The Microchip Technology 1N4994US/TR is a surface mount Zener voltage regulator with a nominal breakdown voltage of 330 V. It operates within a test current range of 4 mA and exhibits a maximum dynamic impedance of 1175 Ohms at the test point, rising to 2200 Ohms near the knee current. The device supports a maximum continuous current of 14.4 mA and withstands surge currents up to 0.25 A for 8.3 ms square waves. It dissipates 5 Watts at an case temperature of 140°C, featuring a thermal resistance of 7°C/W from junction to end cap. The unit functions reliably across temperatures from -65°C to +175°C.

Single Zener Diodes Feature Summary

• Hermetically sealed voidless glass construction with internal metallurgical bonds
• Military qualification compliant with MIL-PRF-19500/356 standards
• Robust design resistant to electrostatic discharge events
• Inherent radiation hardness suitable for harsh environments

Single Zener Diodes Applications

• High-reliability aerospace systems requiring failure-tolerant regulation
• Defense electronics demanding military-grade component stability
• Industrial power supplies operating under extreme thermal conditions

Single Zener Diodes Procurement Notes

Verify that the specific part number matches the required voltage tolerance and suffix specifications. Confirm compliance with MIL-PRF-19500/356 standards if military qualification is mandatory. Ensure the procurement channel provides valid traceability documentation for hermetically sealed components. Check for any specific handling requirements related to the tin/lead or silver end cap finishes mentioned in historical inventory data.

Single Zener Diodes Selection Notes

Select this component when high-voltage regulation is required in a compact surface mount footprint. The 5-watt power rating allows for significant current handling in constrained spaces. Consider the wide operating temperature range for applications exposed to severe environmental fluctuations. Evaluate the low leakage current characteristics for precision reference circuits where minimal drift is critical.

Single Zener Diodes Part Context

This device belongs to the 1N4954US through 1N4996US series of 5-watt Zener regulators. These components are designed for applications where standard discrete diodes lack sufficient power handling or reliability. The series offers a broad selection of voltages from 3.3 to 390 volts, providing engineers with standardized options for various regulation needs without custom ordering.

Single Zener Diodes Replacement Considerations

Equivalent axial-leaded versions exist as 1N4994 without the US suffix. Other series members like 1N4993US or 1N4995US offer different voltage ratings within the same package. Verify pinout compatibility and thermal management requirements when substituting with similar high-power Zener diodes from other manufacturers.