1N4728ATR

Overview

The Fairchild Semiconductor 1N4728ATR is a silicon unidirectional voltage regulator diode designed for general-purpose applications. It operates within the 1N4728A series, providing a nominal Zener voltage of 3.3 V with a tolerance of 5%. The device is housed in a DO-41 glass axial leaded package and supports a power dissipation of 1 W at an ambient temperature of 25°C. Key electrical characteristics include a maximum reverse leakage current of 100 µA and a Zener impedance of 10 Ohms measured at a test current of 76 mA. The component functions reliably across a wide temperature range from -65°C to +200°C.

Feature Summary

• Hermetically sealed double slug type construction utilizing metallurgically bonded oxide passivated die
• DO-41 glass package design ensuring isolation of the case connection
• Unidirectional voltage regulation capability for stable DC circuit operation

Applications

• General purpose voltage regulation in electronic circuits
• Protection against voltage transients and spikes
• Reference voltage sources in low-power designs

Procurement Notes

Verify that the specific suffix 'ATR' corresponds to the tape and reel packaging format rather than cut tape or ammo pack variants when sourcing from distributors. Confirm RoHS compliance status as historical data indicates some manufacturers may offer non-compliant versions. Ensure the supplier provides official datasheets matching the Fairchild Semiconductor specifications for the 1W DO-41 glass Zener diode to guarantee performance parameters such as the 3.3V breakdown voltage and 10 Ohm impedance are met.

Selection Notes

Select this component for applications requiring a precise 3.3V reference point with moderate power handling capabilities. The DO-41 through-hole package facilitates easy integration into standard PCB layouts. Consider the thermal derating requirements above 50°C when designing high-temperature environments. Compare against other 1N47xx series devices if different voltage levels are needed, while maintaining the same physical footprint and power rating constraints.

Part Context

This part belongs to the widely recognized 1N4728A series of one-watt Zener diodes. Originally developed by Motorola and later acquired by NXP, the manufacturing rights and production lines were transferred to Fairchild Semiconductor. The series covers a broad voltage range from 3.3V to 100V, sharing common mechanical features like the DO-41 glass case. This specific variant targets the lower end of the voltage spectrum, offering stable regulation for sensitive logic and analog circuits.

Replacement Considerations

Compatible substitutes include the 1N4728A manufactured by Vishay, onsemi, or Micro Commercial Components. Verify that replacement parts maintain the identical DO-41 package dimensions and 1W power dissipation rating. Cross-reference datasheets to ensure equivalent Zener impedance and leakage current specifications match the original Fairchild Semiconductor design requirements.