1N4749A

Overview

The SMC Diode Solutions 1N4749A is a silicon voltage regulator diode housed in the DO-41 axial leaded package. It provides a nominal Zener voltage of 24 V with a tolerance of ±5%. The device is rated for a maximum power dissipation of 1 W at ambient temperatures up to 75°C, with a derating factor applied above this threshold. Key electrical characteristics include a maximum reverse leakage current of 5 µA at 18.2 V and a dynamic impedance of 25 Ω at the test current of 10.5 mA. The component operates within a junction temperature range of -65°C to +175°C.

Feature Summary

• Hermetically sealed glass passivation ensures long-term reliability and environmental stability.
• High thermal stability supports operation across extended industrial temperature ranges.
• Low dynamic impedance maintains stable voltage regulation under varying load conditions.

Applications

• Voltage reference circuits requiring precise potential levels
• Overvoltage protection stages in power supply inputs
• Clamping applications in signal processing paths

Procurement Notes

Verify the specific manufacturer lot code and date code upon receipt to ensure compliance with project timelines. Confirm RoHS status and halogen-free certification requirements against the latest datasheet revision. Validate that the DO-41 package dimensions match the PCB footprint specifications exactly before assembly.

Selection Notes

Select this component when a standard 24 V regulation point is required in through-hole designs. Ensure the circuit design accounts for the 1 W power dissipation limit and appropriate heat sinking if operating near maximum ratings. Compare dynamic impedance and leakage specifications against alternative manufacturers to guarantee performance parity in sensitive analog sections.

Part Context

The 1N4749A belongs to the widely recognized 1N47xx series of Zener diodes, established as a standard for low-voltage regulation. Manufactured by SMC Diode Solutions, it adheres to JEDEC DO-41 mechanical outlines. This part serves as a fundamental discrete semiconductor element in general-purpose electronics, replacing older equivalents from various legacy vendors while maintaining identical pinout and electrical profiles.

Replacement Considerations

Cross-reference with Vishay 1N4749A or onsemi 1N4749A for direct functional substitution. Verify that alternative sources meet the same ±5% voltage tolerance and 1 W power rating. Ensure the replacement package matches the DO-41 axial form factor for board compatibility.