1N4745A

Overview

The SMC Diode Solutions 1N4745A is a silicon planar Zener diode designed for voltage regulation applications. It features a nominal Zener voltage of 16 V with a tolerance of ±5%. The device is rated for a maximum steady-state power dissipation of 1 W at ambient temperatures up to 50°C, with derating required above this threshold. It utilizes the DO-41 axial leaded package and supports a wide operating temperature range from -65°C to +200°C junction temperature. Key electrical characteristics include a maximum reverse leakage current of 5 µA and a dynamic impedance of 16 Ω at the test current of 15.5 mA.

Feature Summary

• Provides stable voltage reference and regulation in DC circuits through controlled breakdown characteristics.
• Constructed with hermetically sealed glass encapsulation for environmental protection and reliability.
• Capable of operation across an extended industrial temperature range suitable for harsh environments.

Applications

• Voltage regulation in power supply circuits
• Overvoltage protection for sensitive electronic components
• Reference voltage generation in measurement instruments

Procurement Notes

Verify the specific manufacturer marking and date code on the component body to confirm origin from SMC Diode Solutions, as the 1N4745A designation is widely used by multiple semiconductor manufacturers. Ensure the procurement documentation explicitly lists SMC Diode Solutions as the producer to avoid substitution with generic equivalents that may have different quality standards or testing protocols. Cross-reference the datasheet revision number with official SMC publications to ensure compliance with current specifications.

Selection Notes

Select the 1N4745A when a precise 16 V regulation point is required with high thermal stability. The DO-41 package is appropriate for through-hole mounting where higher power dissipation capabilities are needed compared to smaller signal packages. Consider the 1 W power rating and the need for heat sinking if operating near maximum limits in enclosed spaces. Verify that the 5% tolerance meets the circuit requirements for voltage accuracy.

Part Context

The 1N4745A belongs to the standard 1N47xx series of Zener diodes, which are industry-standard parts for general-purpose voltage regulation. This series is characterized by robust construction and consistent performance across various manufacturers. The 16 V variant is commonly used in mid-range voltage applications, bridging the gap between low-voltage references and higher-voltage regulation needs in analog and digital circuits.

Replacement Considerations

Compatible replacements include equivalent 16 V, 1 W Zener diodes in the DO-41 package from other manufacturers, such as Vishay (1N4745A), Microchip (1N4745Ae3), or Rectron (1N4745A-B). Ensure that any substitute part matches the 16 V nominal voltage, ±5% tolerance, and 1 W power dissipation rating. Verify that the replacement's dynamic impedance and leakage current specifications meet or exceed the original design requirements.