LM2676 - 3A Step-Down Switching Voltage Regulator

Overview

The LM2676 is a monolithic integrated circuit designed to provide all the active functions required for a step-down (buck) switching regulator capable of delivering up to 3A of output current. This regulator offers excellent line and load regulation characteristics, making it suitable for a wide range of power supply applications. The device achieves high efficiency (greater than 90%) by utilizing a low ON-resistance DMOS power switch, minimizing power dissipation and maximizing performance.

The LM2676 series is available in fixed output voltage versions of 3.3V, 5V, and 12V, as well as an adjustable output version, providing flexibility for various design requirements. Its robust design and high efficiency make it an ideal choice for both industrial and consumer electronics applications.

Features

• High Efficiency: Up to 94% efficiency, reducing power loss and heat generation.
• Wide Input Voltage Range: Operates from 8V to 40V, accommodating a variety of input sources.
• Adjustable Output Voltage: Versions available with fixed outputs (3.3V, 5V, 12V) or adjustable output via external resistors.
• High Output Current: Capable of delivering up to 3A of continuous output current.
• Low ON-Resistance DMOS Switch: Minimizes conduction losses and improves efficiency.
• Simple Design: Easy to implement with off-the-shelf external components, reducing design complexity.
• Thermal Shutdown Protection: Prevents damage due to excessive temperature.
• Current Limit Protection: Safeguards the regulator and load from overcurrent conditions.
• Frequency Operation: Fixed 260 kHz switching frequency for predictable performance and noise characteristics.

Applications

The LM2676 is versatile and can be used in a wide range of applications, including but not limited to:

• Industrial Power Supplies: Provides stable and efficient power for control systems, motor drives, and instrumentation.
• Consumer Electronics: Ideal for powering devices such as set-top boxes, routers, and audio amplifiers.
• Automotive Systems: Suitable for infotainment systems, lighting, and other 12V automotive applications.
• Telecommunications: Used in base stations, network equipment, and other telecom infrastructure requiring efficient power conversion.
• Computing and Peripherals: Provides power for motherboards, hard drives, and USB hubs.
• Battery-Powered Devices: Efficiently steps down higher battery voltages to lower voltages required by sensitive electronics.

Electrical Characteristics

The following table summarizes the key electrical specifications of the LM2676:

Absolute Maximum Ratings

• Input Voltage (V_IN): 40V
• Output Voltage (V_OUT): Adjustable or fixed (3.3V, 5V, 12V)
• Output Current (I_OUT): 3A (continuous)
• Operating Junction Temperature: -40°C to +125°C
• Storage Temperature: -65°C to +150°C

Typical Performance Characteristics

• Efficiency: Up to 94% (depending on input/output conditions)
• Switching Frequency: 260 kHz (fixed)
• Line Regulation: ±0.1% (typical)
• Load Regulation: ±0.5% (typical)
• Quiescent Current: 5 mA (typical)
• ON-Resistance (R_DS(ON)): 0.15 Ω (typical)

Package Information

The LM2676 is available in several package options to accommodate different thermal and space requirements:

TO-220 Package

• Package Type: Through-hole, 5-pin TO-220
• Thermal Resistance (θ_JA): 50°C/W (typical)
• Dimensions: 10.16 mm x 14.986 mm x 4.572 mm

TO-263 Package

• Package Type: Surface-mount, 5-pin TO-263 (D2PAK)
• Thermal Resistance (θ_JA): 40°C/W (typical)
• Dimensions: 10.16 mm x 9.65 mm x 4.572 mm

LLP Package

• Package Type: Surface-mount, 8-pin LLP (Leadless Leadframe Package)
• Thermal Resistance (θ_JA): 35°C/W (typical)
• Dimensions: 5 mm x 6 mm x 0.8 mm

Conclusion

The LM2676 is a highly efficient, easy-to-use step-down switching regulator that delivers up to 3A of output current. Its robust design, high efficiency, and comprehensive protection features make it suitable for a wide range of applications, from industrial power supplies to consumer electronics. With multiple package options and fixed or adjustable output voltages, the LM2676 provides designers with the flexibility needed to meet diverse power supply requirements.