1N4749UR-1/TR

Overview

The Microchip Technology 1N4749UR-1/TR is a surface mountable 1.0 W glass Zener diode in the DO-213AB (MELF) package. It provides a nominal Zener voltage of 24 V with a standard tolerance of +/- 10%. The device operates within a temperature range of -65°C to +175°C and features a maximum dynamic impedance of 25 Ohms at a test current of 10.5 mA. It includes a maximum reverse current of 5 µA and supports steady-state power dissipation up to 1.00 watts.

Feature Summary

• Hermetically sealed glass MELF package for high reliability applications
• Surface mount design ideal for high density mounting requirements
• Inherently radiation hard per MicroNote 050
• Regulates voltage over a broad operating current and temperature range

Applications

• Voltage regulation in high density electronic circuits
• High reliability applications requiring source control drawings
• Low parasitic requirement circuit designs

Procurement Notes

Verify that the ordering suffix TR indicates tape and reel packaging as specified in the datasheet. Confirm the specific tolerance level, as the base part number without an A suffix denotes a +/- 10% tolerance. Ensure compatibility with the DO-213AB footprint and check for any required screening prefixes like MQ or MX if MIL-PRF-19500 standards are necessary for the application.

Selection Notes

Select this component when a surface mount equivalent to the axial 1N4749 is required. It offers electrical equivalence to the JEDEC registered 1N4728 through 1N4764 series but utilizes the DO-213AB outline. Consider its radiation hardness and hermetic sealing for environments where standard plastic packages may be insufficient. Verify thermal derating curves if ambient temperatures exceed recommended limits.

Part Context

This device belongs to the 1N4728UR through 1N4764AUR series of surface mount 1.0 W glass Zener diodes manufactured by Microsemi (now Microchip Technology). These components serve as direct surface mount replacements for traditional axial-leaded Zener diodes, maintaining identical electrical characteristics while adapting to modern PCB assembly techniques via the DO-213AB package.

Replacement Considerations

Direct surface mount equivalents include the MLL4749A series. Axial leaded replacements are available as the 1N4749 or 1N4749A. Ensure the replacement matches the DO-213AB footprint dimensions and maintains the required 1.0 W power dissipation capability.