1N4728A

Overview

The SMC Diode Solutions 1N4728A is a silicon planar Zener diode designed for voltage regulation and protection applications. It features a hermetically sealed glass DO-41 package with metallurgically bonded construction. The device provides a nominal Zener voltage of 3.3 V with a tolerance of ±5%. It supports a maximum DC power dissipation of 1 W at 25°C, derating linearly above this temperature. Key electrical characteristics include a maximum reverse leakage current of 100 µA and a Zener impedance of 10 Ω at the test current of 76 mA. The component operates within a junction temperature range of -65°C to +200°C.

Feature Summary

• Hermetically sealed glass construction with double slug type design for robust environmental resistance
• Oxide passivated die structure ensuring stable voltage regulation performance
• Metallurgically bonded internal connection providing reliable thermal and mechanical stability

Applications

• Low current voltage regulation circuits
• Input voltage protection for microcontrollers and ICs
• General purpose voltage reference applications

Procurement Notes

Verify manufacturer origin as SMC Diode Solutions specifically, as the 1N4728A designation is widely produced by multiple vendors including Vishay, onsemi, and Nexperia. Confirm RoHS compliance status if required, as some legacy or specific suffix variants may not meet modern environmental standards. Ensure the DO-41 axial leaded package matches the target PCB footprint requirements.

Selection Notes

Select this component when a precise 3.3 V reference is needed in a through-hole environment. The 1 W power rating allows for higher current handling compared to 500 mW variants, suitable for moderate load conditions. Verify that the ±5% tolerance meets the circuit's precision requirements. Consider thermal management strategies if operating near the maximum power dissipation limit in enclosed spaces.

Part Context

The 1N4728A belongs to the standard 1N47xx series of Zener diodes, which are industry-standard part numbers defined by JEDEC. This series covers a wide voltage range from 3.3 V to 100 V. The 'A' suffix typically denotes the ±5% tolerance band. As a through-hole device, it is commonly used in prototyping, industrial control panels, and consumer electronics where axial mounting is preferred over surface mount technologies.

Replacement Considerations

Direct functional equivalents include Vishay 1N4728A, onsemi 1N4728A, Nexperia 1N4728A, and Motorola/NXP 1N4728A. All share identical electrical specifications and DO-41 packaging. Substitutes must be verified for pinout compatibility and thermal derating curves.