1N4748A

Overview

The SMC Diode Solutions 1N4748A is a single silicon zener diode housed in a DO-41 axial glass package. It provides a nominal zener voltage of 22 V with a tolerance of ±5%. The device supports a maximum steady-state power dissipation of 1 W at ambient temperatures up to 50°C, requiring derating above this threshold. Key electrical characteristics include a maximum reverse leakage current of 100 nA and a zener impedance of 23 Ohms measured at a test current of 11.5 mA. The component operates within a temperature range of -65°C to +175°C.

Feature Summary

• Hermetically sealed glass passivated construction for environmental stability
• Unidirectional voltage regulation capability
• Axial leaded through-hole mounting configuration

Applications

• Voltage reference circuits
• Overvoltage protection stages
• Clamping applications in power supplies

Procurement Notes

Verify the specific manufacturer designation on the datasheet, as the 1N4748A is a generic JEDEC part number produced by multiple vendors including Microchip, Vishay, and ON Semiconductor. Confirm RoHS compliance status and packaging type (reel vs. bulk) directly with the supplier, as these attributes vary significantly across different production sources and are not inherent to the base model number.

Selection Notes

Select this component when a standard 22 V regulation point is required in through-hole designs. Ensure the circuit can accommodate the 1 W power rating and that the operating environment stays within the specified thermal limits. Verify that the 23 Ohm dynamic impedance meets the noise and regulation requirements of the target application compared to lower-impedance alternatives.

Part Context

This component belongs to the widely recognized 1N47xx series of one-watt zener diodes. The series covers a broad spectrum of voltage ratings from 3.3 V to 75 V, utilizing the same DO-41 glass axial package format. The 1N4748A specifically addresses the mid-range voltage segment, offering a balance between current handling and voltage precision for general-purpose electronic systems.

Replacement Considerations

Direct functional substitutes include the 1N4748A variants from other manufacturers such as Microchip Technology, Vishay Intertechnology, and ON Semiconductor. Cross-referencing should confirm identical pinout, package dimensions, and electrical tolerances to ensure compatibility without circuit modification.