1N4705

Overview

The Microchip Technology 1N4705 is a 0.5 W axial-leaded Zener diode housed in a hermetically sealed glass DO-7 (DO-204AA) package. It provides an 18 V nominal Zener voltage with a standard ±5% tolerance. The device operates within a temperature range of -65°C to +175°C and features an internally metallurgical-bonded construction. Electrical characteristics include a Zener test current of 50 µA, a maximum reverse leakage current of 0.05 µA at 5 V, and a maximum DC Zener current of 26.4 mA.

Feature Summary

• Internally solder bonded for enhanced reliability
• Hermetically sealed glass axial-lead construction
• Capable of regulating voltage across a broad operating current and temperature range
• Inherently radiation hard

Applications

• Voltage regulation circuits requiring low operating currents
• Reference voltage sources in precision applications
• Protection against overvoltage transients
• Military and aerospace electronic systems

Procurement Notes

Verify the specific manufacturer origin, as the 1N4705 designation is JEDEC registered and produced by multiple vendors including Microsemi/Microchip, Central Semiconductor, and others. Confirm that the required package matches the DO-7 axial lead form factor and ensure compliance with any necessary military screening prefixes if applicable to the intended environment.

Selection Notes

Select this component when a 0.5 W power dissipation rating and an 18 V breakdown voltage are required. The DO-7 glass package offers high thermal stability and hermetic sealing suitable for harsh environments. Consider tighter tolerance suffixes or alternative packages if standard 5% accuracy or surface mount mounting is preferred.

Part Context

This part belongs to the 1N4678 through 1N4717 series of 0.5 W Zener voltage regulators. The series covers a voltage selection from 1.8 V to 43 V. These devices are characterized by their low test current of 50 µA and internal metallurgical bonding, distinguishing them from standard planar diodes.

Replacement Considerations

Equivalent parts include the 1N4705A and other generic 1N4705 variants from different manufacturers. Surface mount equivalents are available in the DO-213AA outline, such as the 1N4705UR.