1N4678 (DO35)

Overview

The Microsemi Corporation 1N4678 is a single silicon Zener diode housed in a hermetically sealed glass DO-35 (DO-204AA) axial-leaded package. It provides a nominal reference voltage of 1.8 V with a standard tolerance of plus or minus 5%. The device supports a maximum power dissipation of 0.417 W and operates within a temperature range extending up to 200 °C. This component serves as the axial-leaded equivalent to the surface-mount 1N4678UR series.

Feature Summary

• Hermetically sealed glass construction for environmental protection
• Internal metallurgical bond option available by adding a "-1" suffix
• Inherently radiation hard design suitable for harsh environments
• Minimal capacitance characteristics

Applications

• Voltage regulation over broad operating current ranges
• Temperature compensation circuits
• Reference voltage generation
• Protection against electrostatic discharge per MIL-STD-750 Method 1020

Procurement Notes

Verify the specific suffix configuration, as the base part number denotes commercial grade while suffixes like "-1" indicate internal metallurgical bonding and potential military screening. Confirm RoHS compliance status, as standard versions may not be compliant. Ensure the required voltage tolerance matches the standard 5% specification unless tighter tolerances are explicitly ordered via designated suffix codes.

Selection Notes

Select this component when an axial-leaded form factor is required instead of the surface-mount DO-213AA variant. Consider the "-1" suffix if internal metallurgical bonding is necessary for high-reliability applications. Verify that the 1.8 V breakdown voltage aligns with circuit requirements, noting that lower test currents are utilized for tight tolerance variants.

Part Context

This component belongs to the JEDEC registered 1N4678 through 1N4717 series of 0.5 watt Zener voltage regulators. It functions as the axial-leaded counterpart to the MLL4678 surface-mount device. The series offers a selection of voltages from 1.8 to 43 volts, providing designers with standardized options for low-power voltage regulation tasks across various industrial and military specifications.

Replacement Considerations

The surface-mount equivalent is the 1N4678UR. For hermetic sealing with internal metallurgical bonding, consider the 1N4678-1.