1N4738UR

Overview

The Microchip Technology 1N4738UR is a single silicon Zener diode designed for voltage regulation and protection applications. It features an 8.2V nominal Zener voltage with a 5% tolerance and a 1W power dissipation rating at specified temperatures. The device utilizes a DO-213AB (MELF) glass axial package, providing a compact surface-mount form factor. Key electrical characteristics include a maximum reverse leakage current of 10µA at the rated voltage and a test current typically associated with standard 1W Zener specifications. The component operates as a unidirectional voltage reference.

Feature Summary

• Provides stable voltage regulation using a single Zener junction
• Utilizes a compact MELF glass axial package for surface-mount integration
• Designed for general-purpose voltage clamping and reference applications

Applications

• Voltage regulation in power supply circuits
• Overvoltage protection for sensitive electronic components
• Reference voltage generation in analog signal processing

Procurement Notes

Verify the specific suffix designation upon ordering, as Microchip may offer variations such as UR or UR-1 which can indicate differences in tape-and-reel packaging or specific manufacturing lot attributes. Confirm that the MELF glass package aligns with your PCB footprint requirements. Ensure compliance with RoHS directives if required by your final assembly standards, noting that older revisions or specific suffixes may have different environmental certifications.

Selection Notes

Select this component when a surface-mount Zener diode with a 1W power rating and 8.2V breakdown voltage is required. The MELF package offers advantages in space-constrained designs compared to traditional through-hole DO-41 packages. Consider the thermal derating curves provided in the datasheet for high-temperature environments. Verify that the 10µA leakage current specification meets the requirements of your specific circuit design.

Part Context

The 1N4738 series is a widely recognized family of Zener diodes used in industrial and consumer electronics. The UR variant specifically denotes the surface-mount MELF configuration, distinguishing it from the through-hole DO-41 versions like the 1N4738A. This transition allows for automated assembly processes while maintaining the robust performance characteristics associated with the legacy 1N47xx series numbering system.

Replacement Considerations

Equivalent parts include the Nexperia 1N4738A in DO-41 packaging for through-hole replacements, though package compatibility must be addressed. Surface-mount equivalents should be sourced from manufacturers offering identical 8.2V/1W MELF specifications. Cross-reference part numbers such as 1N4738UR-1/TR for specific reel configurations.