LM2576D2T-005G Datasheet, Specifications, Applications, and Regulator Circuit

The LM2576D2T-005G regulator belongs to monolithic integrated circuits ideally suited for easy and convenient design of a step−down switching regulator (buck converter). it is capable of driving a 3.0 A load with excellent line and load regulation. And it is available in fixed output voltages of 3.3 V, 5.0 V, 12 V, 15 V, and an adjustable output version. This type regulator was designed to minimize the number of external components to simplify the power supply design. Standard series of inductors optimized for use with the LM2576 are offered by several different inductor manufacturers. Since the LM2576 converter is a switch−mode power supply, its efficiency is significantly higher in comparison with popular three−terminal linear regulators, especially with higher input voltages. In many cases, the power dissipated is so low that no heatsink is required or its size could be reduced dramatically.

Figure 1: LM2576D2T-005G Step-down Buck Switching Regulator IC (Fixed 5V 1 Output 3A TO-263-6, 5 Leads + Tab, TO-263BA)

LM2576D2T-005G Specifications and Features

Features

• 3.3 V, 5.0 V, 12 V, 15 V, and Adjustable Output Versions
• Adjustable Version Output Voltage Range, 1.23 to 37 V ±4% Maximum Over Line and Load Conditions
• Guaranteed 3.0 A Output Current
• Wide Input Voltage Range
• Requires Only 4 External Components
• 52 kHz Fixed Frequency Internal Oscillator
• TTL Shutdown Capability, Low Power Standby Mode
• High Efficiency
• Uses Readily Available Standard Inductors
• Thermal Shutdown and Current Limit Protection
• Moisture Sensitivity Level (MSL) Equals 1
• Pb−Free Packages are Available

Datasheet Download

Block Diagram and Typical Application

Figure 2: Block Diagram and Typical Application

Applications

• Simple High−Efficiency Step−Down (Buck) Regulator
• Efficient Pre−Regulator for Linear Regulators
• On−Card Switching Regulators
• Positive to Negative Converter (Buck−Boost)
• Negative Step−Up Converters
• Power Supply for Battery Chargers

Alternate Parts

• LM2576D2TR4-5G

• LM2576-5.0WU-TR

• LM2576D2TR4-005

• LM2576D2T-005

Buck Circuit Basic

Buck Switching Regulator Circuit

Buck regulator circuits use switching elements (usually power MOSFETs), energy storage elements (usually inductors) and other electronic components to convert a higher input voltage into a lower output voltage. Its basic principle is to change the flow of current in a circuit by periodically turning switching elements on and off. By adjusting the switching time, the stability and accuracy of the output voltage can be controlled. When the switch turns on, the inductor stores energy and allows current to continue flowing; when the switch turns off, the inductor releases the stored energy, providing the required step-down output through the output end. Buck switching circuits are commonly used in various applications, such as power adapters, battery chargers, dimmable LED drivers, etc., where high voltage needs to be converted to low voltage.

It should be noted that the advantages and disadvantages of the Buck circuit may vary depending on the specific design conditions and requirements. Therefore, specific limitations need to be considered when choosing to use a Buck circuit.

Seven Principles of BUCK Circuit Layout on PCB

1) Place the input capacitor and diode on the same side as the IC pins and as close to the IC as possible.

2) Heat dissipation holes can be provided if necessary.

3) The inductor is used to reduce the radiation noise from the switching node to a greater extent, and its importance is no less than that of the input capacitor, so it also needs to be placed close to the IC.

4) The copper foil graphic area should not be too large.

5) The output capacitor is arranged near the inductor.

6) The wiring of the feedback path should be kept away from noise sources such as inductors and diodes as much as possible.

7) Corner wiring should be in an arc shape.