1N4728A

Overview

The Fairchild Semiconductor 1N4728A is a silicon Zener voltage regulator diode designed for hermetically sealed applications. It features a DO-41 glass package with double slug construction and oxide passivated die technology. The device provides a nominal Zener voltage of 3.3V with a tolerance of ±5%. Rated for a maximum power dissipation of 1W, it operates within a temperature range of -65°C to +200°C. Key electrical characteristics include a knee impedance of 400 Ω and a test current of 76 mA.

Feature Summary

• Hermetically sealed glass construction utilizing metallurgically bonded double slug design
• Oxide passivated silicon planar die for enhanced reliability
• Wide operating temperature range suitable for demanding environments

Applications

• Voltage regulation circuits requiring stable reference voltages
• Overvoltage protection for sensitive electronic components
• Clamping applications in signal processing paths

Procurement Notes

Verify the specific manufacturer source when sourcing this component, as multiple vendors produce identical part numbers under the 1N4728A designation. Confirm that the received units match the DO-41 package style and glass construction specified by Fairchild. Ensure compliance with required environmental ratings if operating near the upper temperature limits.

Selection Notes

Select this component when a low-voltage reference of 3.3V is required with high thermal stability. The 1W power rating allows for higher current handling compared to half-watt variants. Consider the DO-41 axial leaded package for through-hole mounting requirements where hermetic sealing is necessary for long-term durability.

Part Context

This device belongs to the 1N4728A series of one-watt Zener diodes produced by Fairchild Semiconductor. The series covers a broad voltage range from 3.3V to 100V, sharing common mechanical and thermal specifications. It serves as a standard solution for general-purpose voltage regulation in industrial and commercial electronics.

Replacement Considerations

Equivalent parts include the Motorola/NXP 1N4728A and ON Semiconductor 1N4728A. These alternatives share identical electrical parameters and package dimensions, allowing for direct substitution in existing designs without circuit modification.