1N4749ATR

Overview

The Fairchild Semiconductor 1N4749ATR is a single-channel general-purpose Zener diode designed for voltage regulation applications. It features a nominal Zener voltage of 24 V with a tolerance of ±5%. The device is housed in a DO-41 axial leaded glass package, suitable for through-hole mounting. It supports a maximum power dissipation of 1 W and operates within a temperature range from -65°C to +200°C. Key electrical parameters include a test current of 10.5 mA, a maximum Zener impedance of 25 Ω, and a maximum reverse leakage current of 5 μA.

Feature Summary

• Provides stable voltage regulation at a nominal 24 V level with tight manufacturing tolerances.
• Utilizes a hermetically sealed glass passivated construction for reliable performance in harsh environments.
• Capable of handling high thermal loads with a maximum power dissipation rating of 1 W.

Applications

• Low voltage stabilizers
• Voltage reference circuits
• Overvoltage protection

Procurement Notes

Verify the specific manufacturer designation when sourcing, as the 1N4749A specification is widely produced by multiple semiconductor vendors including onsemi, Microchip, and Vishay. Ensure the component matches the required DO-41 package dimensions and terminal configurations for your PCB layout. Confirm that the supplier provides documentation verifying compliance with the standard JEDEC DO-204 mechanical outline.

Selection Notes

Select this component for designs requiring a robust, high-power axial Zener diode. The 1 W dissipation rating allows for effective heat management without additional heatsinking in many scenarios. The wide operating temperature range makes it suitable for industrial applications where environmental stability is critical. Consider the 5% voltage tolerance when designing precision reference circuits.

Part Context

The 1N4749A belongs to the standard 1N47xx series of silicon Zener diodes, which are industry-standard components for basic voltage regulation tasks. This series typically covers a voltage range from approximately 3.3 V to 200 V, with the 1N4749A specifically targeting the 24 V segment. These devices are foundational elements in analog electronics, often used in power supply feedback loops and signal conditioning stages.

Replacement Considerations

Direct substitutes include the 1N4749AG/TR manufactured by Microchip Technology and the 1N4749A-TAP produced by Vishay Semiconductors. Both alternatives maintain the same 24 V nominal voltage, 1 W power rating, and DO-41 package form factor. Verify that any replacement part meets the specific leakage current and impedance requirements of your circuit design.