LM2575N 5

LM2575N-5: 5V Step-Down Switching Regulator

Overview

The LM2575N-5 is a monolithic integrated circuit belonging to the LM2575 series of step-down (buck) switching regulators. Designed for simplicity and efficiency, this regulator provides all the active functions required to deliver a fixed 5V output with a load capability of up to 1A. The device offers excellent line and load regulation, making it suitable for a wide range of power supply applications. With its built-in protection features and minimal external component requirements, the LM2575N-5 is an ideal choice for designers seeking a robust and reliable voltage regulation solution.

Features

• Fixed 5V Output Voltage with ±4% tolerance under specified conditions
• High Efficiency up to 88%, reducing heat dissipation
• 1A Output Current capability with excellent load regulation
• Wide Input Voltage Range from 4.75V to 40V
• Low Standby Current of 50 µA (typical) in shutdown mode
• Internal Frequency Compensation simplifies circuit design
• Cycle-by-Cycle Current Limiting for overload protection
• Thermal Shutdown for full protection under fault conditions
• ±10% Oscillator Frequency Tolerance ensures stable operation
• Requires Minimal External Components for a complete regulator solution

Applications

The LM2575N-5 is versatile and finds use in numerous applications, including:

• Industrial power supplies
• Automotive electronics
• Battery chargers
• Distributed power systems
• Consumer electronics
• Telecommunications equipment
• Embedded systems
• LED drivers
• Point-of-load regulation

Electrical Characteristics

The following table summarizes the key electrical characteristics of the LM2575N-5 under typical operating conditions (TA = 25°C, unless otherwise specified):

• Output Voltage: 5V ±4%
• Input Voltage Range: 4.75V to 40V
• Output Current: Up to 1A
• Standby Current: 50 µA (typical)
• Switching Frequency: 52 kHz (typical)
• Efficiency: Up to 88%
• Current Limit Threshold: 1.5A (typical)
• Thermal Shutdown Temperature: 150°C (typical)

Package Information

The LM2575N-5 is available in a standard 5-lead TO-220 package, which provides excellent thermal performance and ease of mounting. The package dimensions and pin configuration are as follows:

• Package Type: TO-220-5
• Package Dimensions: 10.16mm x 8.89mm x 4.45mm
• Pin Configuration:
  • Pin 1: Input Voltage (VIN)
  • Pin 2: Output Voltage (VOUT)
  • Pin 3: Ground (GND)
  • Pin 4: Feedback (FB) - Connected to GND for fixed output version
  • Pin 5: ON/OFF Control (Shutdown)
• Thermal Resistance (Junction-to-Air): 50°C/W (typical)
• Operating Temperature Range: -40°C to +125°C

Typical Application Circuit

A basic application circuit for the LM2575N-5 requires only a few external components:

• Input capacitor (typically 100µF electrolytic)
• Output capacitor (typically 1000µF electrolytic)
• Schottky diode (1N5822 or equivalent)
• Inductor (typically 100µH)

Design Considerations

When designing with the LM2575N-5, consider the following:

• Input Capacitor: Must be placed close to the VIN and GND pins to minimize high-frequency noise
• Output Capacitor: Affects regulator stability and transient response
• Inductor Selection: Critical for maintaining continuous conduction mode operation
• Thermal Management: Ensure adequate heat sinking for high current applications
• PCB Layout: Keep high current paths short and use proper grounding techniques

Conclusion

The LM2575N-5 provides a simple, efficient solution for step-down voltage regulation applications. With its robust feature set, including thermal shutdown and current limiting, it offers reliable performance in demanding environments. The fixed 5V output version eliminates the need for external feedback components, further simplifying design. Whether for industrial, automotive, or consumer applications, the LM2575N-5 delivers excellent performance with minimal external components, making it an excellent choice for a wide range of power conversion needs.