1N4974

Single Zener Diodes Overview

The Microchip Technology 1N4974 is a military-qualified, voidless hermetically sealed glass Zener diode rated for 5 watts of power dissipation. It features a nominal Zener voltage of 47 V with a standard tolerance of ±5%. The device operates within a junction temperature range of -65°C to +175°C and utilizes an axial lead 'E' package. Key electrical characteristics include a maximum reverse leakage current of 2 µA at the specified voltage, a Zener impedance of 25 Ohms at the test current, and a positive temperature coefficient of 0.095 %/°C.

Single Zener Diodes Feature Summary

• Hermetically sealed construction using voidless hard glass with tungsten slugs and internal metallurgical bonds for extreme robustness.
• Military qualification compliant with MIL-PRF-19500/356 standards for high-reliability applications where failure is not tolerated.
• Inherently radiation hard and non-sensitive to electrostatic discharge (ESD) per MIL-STD-750 Method 1020.

Single Zener Diodes Applications

• High-reliability aerospace and defense circuits
• Critical voltage regulation in harsh environments
• Radiation-hardened electronic systems

Single Zener Diodes Procurement Notes

Verify that the specific ordering suffix matches the required tolerance level, as standard parts carry a 5% tolerance while tighter tolerances require specific suffixes. Confirm compliance with MIL-PRF-19500/356 if military qualification is mandatory. Ensure the procurement specification explicitly requests the axial lead configuration and tin/lead finish, noting that previous inventory may have differed. Validate that the component meets the required thermal derating curves for the intended operating environment.

Single Zener Diodes Selection Notes

Select the 1N4974 when a stable 47 V reference is needed in high-power, high-reliability scenarios. This component is suitable for designs requiring operation up to +175°C junction temperature. Consider the positive temperature coefficient for thermal stability requirements. For surface-mount needs, evaluate the equivalent US series devices. Ensure the circuit design accounts for the 5 W power rating and appropriate heat sinking or lead mounting constraints.

Single Zener Diodes Part Context

The 1N4974 belongs to the industry-recognized 1N4954 through 1N4996 series of 5 Watt Zener Voltage Regulators manufactured by Microsemi (now Microchip Technology). These components are designed for applications demanding high reliability and durability. The series offers a wide selection of voltages from 3.3 V to 390 V, all sharing the same robust voidless-glass package and military-grade construction standards.

Single Zener Diodes Replacement Considerations

Direct replacements must match the 47 V nominal voltage, 5 W power rating, and axial lead package. Verify that any substitute also meets MIL-PRF-19500/356 if military qualification is required. Surface-mount equivalents are available in the 1N4974US series but require different footprint considerations.