3A, 52kHz, Step-Down Switching Regulator
z 3.3V, 5.0V, 12V and Adjustable Output Versions
z Adjustable Version Output Voltage Range, 1.23 to 37V
+/- 4% AG10Maximum Over Line and Load Conditions
z Guaranteed 3.0A Output Current
z Wide Input Voltage Range
z Requires Only 4 External Components
z 52kHz Fixed Frequency Internal Oscillator
z TTL Shutdown Capability, Low Power Standby Mode
z High Efficiency
z Uses Readily Available Standard Inductors
z Thermal Shutdown and Current Limit Protection
z Moisture Sensitivity Level 3 for SMD packages
z Simple High-Efficiency Step-Down(Buck) Regulator
z Efficient Pre-Regulator for Linear Regulators
z On-Card Switching Regulators
z Positive to Negative Converter(Buck-Boost)
z Negative Step-Up Converters
z Power Supply for Battery Chargers
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
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.
Dec 2011 – Rev. 1.3