LM2576-ADJ Stepˆ’Down Switching Regulator (SMD)

Description

The LM2576 regulators are monolithic integrated circuits ideally suited for the easy and convenient design of a step–down switching regulator (buck converter). The circuit can drive a 3.0 A load with excellent line and load regulation. The device is available in an adjustable output version. The regulator minimises the number of external components to simplify the power supply design.  Several different inductor manufacturers offer standard series of inductors optimised for use with the LM2576.

Since the LM2576 converter is a switch-mode power supply, its efficiency is significantly higher than the popular three-terminal linear regulators, especially with higher input voltages.

The LM2576 features include a guaranteed ±4% tolerance on output voltage within specified input voltages and output load conditions and ±10% on the oscillator frequency (±2% over 0°C to 125°C). External shutdown is included, featuring 80 A (typical) standby current. The output switch includes cycle−by−cycle current limiting and thermal shutdown for full protection under fault conditions.

Pin Configuration

Features

• Adjustable Version Output Voltage Range, 1.23 to 35V ± 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

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

Specification