1N4728A

1N4728A: Low Voltage Regulator Diode

Overview

The 1N4728A is a low voltage regulator diode designed for precision voltage regulation in a variety of electronic circuits. It is part of a series of 22 diodes with nominal working voltages ranging from 3.3V to 24V, making it suitable for applications requiring stable reference voltages. The diode is housed in a hermetically sealed SOD66 (DO-41) package, ensuring durability and reliability in harsh environments. Its robust construction and consistent performance make it a preferred choice for engineers working on power supply designs, voltage clamping, and signal conditioning circuits.

Features

• Total Power Dissipation: Designed to handle significant power loads while maintaining stable operation.
• Hermetically Sealed Package: The SOD66 (DO-41) package provides excellent environmental protection, ensuring long-term reliability.
• Wide Voltage Range: Available in 22 variants with nominal working voltages from 3.3V to 24V.
• Low Dynamic Impedance: Ensures minimal voltage fluctuations under varying load conditions.
• High Surge Current Capability: Can withstand transient overloads without degradation in performance.
• Precision Voltage Regulation: Tight tolerance on breakdown voltage ensures consistent performance across applications.

Applications

The 1N4728A is widely used in electronic circuits where precise voltage regulation is critical. Below are some common applications:

• Voltage Regulation: Used as a shunt regulator in power supplies to maintain a constant output voltage.
• Overvoltage Protection: Acts as a clamping device to protect sensitive components from voltage spikes.
• Signal Conditioning: Provides stable reference voltages in analog and mixed-signal circuits.
• Voltage Reference: Serves as a precision reference in measurement and instrumentation systems.
• Switching Circuits: Used in high-speed switching applications due to its fast response time.

Electrical Characteristics

The following table summarizes the key electrical characteristics of the 1N4728A:

• Nominal Working Voltage (Vz): 3.3V to 24V (depending on variant)
• Test Current (Izt): Typically 20mA
• Maximum Dynamic Impedance (Zzt): 10Ω at Izt
• Maximum Reverse Leakage Current (Ir): 5μA at 1V below Vz
• Maximum Power Dissipation (Pd): 1.3W at 25°C ambient temperature
• Operating Temperature Range: -65°C to +200°C
• Surge Current (Ipp): 50A (8/20μs pulse)

Package Information

The 1N4728A is housed in a SOD66 (DO-41) package, which is a hermetically sealed glass passivated diode package. Below are the key dimensions and mechanical specifications:

• Package Type: SOD66 (DO-41)
• Body Diameter: 2.7mm (max)
• Body Length: 5.2mm (max)
• Lead Diameter: 0.71mm (nominal)
• Lead Spacing: 10.2mm (min)
• Weight: Approximately 0.35g
• Material: Glass passivated junction with high-temperature solder

Thermal Characteristics

The thermal performance of the 1N4728A is critical for ensuring reliable operation under varying load conditions. The following parameters define its thermal behavior:

• Thermal Resistance (Junction to Ambient): 100°C/W
• Maximum Junction Temperature (Tj): 200°C
• Storage Temperature Range: -65°C to +200°C

Reliability and Testing

The 1N4728A undergoes rigorous testing to ensure compliance with industry standards and reliability requirements. Key tests include:

• High-Temperature Reverse Bias (HTRB): Evaluates long-term stability under reverse bias conditions.
• Temperature Cycling: Assesses performance under repeated thermal stress.
• Humidity Testing: Ensures resistance to moisture-related degradation.
• Mechanical Shock and Vibration: Validates durability in harsh mechanical environments.

Conclusion

The 1N4728A is a versatile and reliable low voltage regulator diode suitable for a wide range of applications requiring precise voltage regulation. Its hermetically sealed SOD66 (DO-41) package, combined with excellent electrical and thermal characteristics, makes it an ideal choice for demanding environments. Whether used in power supplies, overvoltage protection circuits, or signal conditioning applications, the 1N4728A delivers consistent performance and long-term reliability.