1N4705UR-1/TR

Overview

The 1N4705UR-1/TR is a single silicon epitaxial planar Zener diode manufactured by Microchip Technology. It features an 18V nominal Zener voltage with a ±5% tolerance and a maximum power dissipation of 0.5W (500mW). The device utilizes the DO-213AA surface-mount package, also known as MELF or SOD-80. It operates within a temperature range of -65°C to +175°C junction temperature. The component is unidirectional and hermetically sealed in glass.

Feature Summary

• Hermetically sealed glass encapsulation for environmental protection
• Surface-mount DO-213AA package design
• High operating junction temperature capability up to 175°C

Applications

• Voltage regulation circuits
• Overvoltage protection
• Reference voltage generation

Procurement Notes

Verify the specific ordering suffix UR-1/TR against the manufacturer's current datasheet to confirm exact mechanical dimensions and marking codes. Ensure compliance with RoHS directives if required, as historical data indicates non-compliance for some variants in this series. Confirm lead times directly with authorized distributors.

Selection Notes

Select this component when a hermetically sealed, high-reliability Zener diode is required for surface-mount applications. The 18V rating and 0.5W power dissipation define its electrical limits. Consider the DO-213AA footprint compatibility during PCB layout. Verify thermal management requirements given the 175°C maximum junction temperature specification.

Part Context

This part belongs to the 1N47xx series of Zener diodes, adapted for surface-mount technology. While traditional 1N47xx parts use axial DO-35 packages, the UR-1 variant adapts the electrical characteristics to the DO-213AA MELF form factor. This allows for automated assembly while maintaining the reliability standards associated with hermetic sealing.

Replacement Considerations

Direct substitutes include other manufacturers' DO-213AA packaged Zener diodes with identical 18V and 0.5W ratings. Cross-reference with Microsemi/Microchip legacy equivalents. Verify pinout orientation and thermal resistance values before substitution.