3A, 52kHz, Step-Down Switching Regulator

LM2576

Dec 2011 – Rev. 1.3

- 1

-

HTC

FEATURES

3.3V, 5.0V, 12V and Adjustable Output Versions

Adjustable Version Output Voltage Range, 1.23 to 37V

+/- 4% AG10Maximum Over Line and Load Conditions

Guaranteed 3.0A Output Current

Wide Input Voltage Range

Requires Only 4 External Components

52kHz 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 3 for SMD packages

APPLICATION

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

SOP8-PP PKG

TO-220 PKG

TO-263 PKG

ORDERING INFORMATION

Device

Marking

Package

LM2576DP-X.X

LM2576-X.X

SOP8-PP

LM2576T-X.X

LM2576-X.X

TO-220

LM2576R-X.X

LM2576-X.X

TO-263

DESCRIPTION

The LM2576 series of regulators are monolithic integrated circuits ideally suited for easy and convenient

design of a step-down switching regulator (buck converter).

All circuits of this series are capable of driving a 3.0A load with excellent line and load regulation. These

devices are available in fixed output voltages of 3.3V, 5.0V, 12V and an adjustable output version.

These regulators were 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. A standard series of inductors optimized for use with the LM2576 are available from several

different manufacturers. This feature greatly simplifies the design of switch-mode power supplies. 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㎂(typical) standby current. The output switch includes cycle-

bycycle current limiting, as well as thermal shutdown for full protection under fault conditions.