1N4738A

Overview

The onsemi 1N4738A is a single-channel Zener diode designed for voltage regulation applications. It features an 8.2 V nominal Zener voltage with a ±5% tolerance and operates within a power dissipation rating of 1 W at 25°C ambient temperature. The device utilizes a DO-41 through-hole package, ensuring compatibility with standard axial lead mounting techniques. Key electrical characteristics include a maximum reverse leakage current of 10 µA and a Zener impedance of 4.5 Ω at the test current of 31 mA. It supports a wide operating temperature range from -65°C to +200°C, providing robust performance in demanding environments.

Feature Summary

• Provides stable voltage regulation with a nominal 8.2 V output and tight ±5% tolerance.
• Features low dynamic impedance for effective noise filtering and signal conditioning.
• Constructed with a glass-passivated junction to ensure high reliability and stability.
• Capable of handling high surge currents while maintaining consistent regulation under varying load conditions.

Applications

• General-purpose voltage reference circuits requiring precise potential levels.
• Overvoltage protection stages in power supply input lines.
• Clamping applications to limit transient voltage spikes in sensitive electronic systems.
• Biasing networks for transistor amplifiers and other active components.

Procurement Notes

Verify the specific manufacturer prefix or suffix against official datasheets to confirm exact electrical tolerances and package variations. Ensure the component meets required RoHS compliance standards for your target market. Cross-reference the JEDEC DO-41 footprint dimensions with your PCB layout to guarantee mechanical fit. Confirm thermal derating curves if operation exceeds 25°C ambient temperature to prevent power dissipation limits from being exceeded during continuous use.

Selection Notes

Select this component when a standard 8.2 V regulation point is required in a through-hole assembly. Consider the 1 W power rating and thermal resistance values if heat dissipation is a primary design constraint. Evaluate the ±5% voltage tolerance against circuit sensitivity requirements. Compare the Zener impedance value with alternative packages to determine suitability for high-frequency noise suppression tasks where lower impedance improves regulation accuracy.

Part Context

The 1N4738A belongs to the widely recognized 1N47xx series of silicon Zener diodes, established as a standard for general-purpose voltage regulation. Manufactured by onsemi, this part leverages mature semiconductor processes to deliver consistent performance across automotive and industrial sectors. The DO-41 glass encapsulation offers superior thermal conductivity compared to plastic alternatives, supporting higher operating temperatures and reliable long-term operation in harsh environmental conditions.

Replacement Considerations

Equivalent parts include Vishay 1N4738A-E1 and Nexperia 1N4738A/133. Verify pinout polarity and package dimensions before substitution. Microsemi MV1N4738APTR offers a plastic variant with similar electrical characteristics but different thermal properties. Ensure replacement devices meet the same ±5% voltage tolerance and 1 W power dissipation ratings for direct interchangeability.