LM2576xx Series SIMPLE SWITCHER® 3-A Step-Down Voltage Regulator
Description
The LM2576 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving 3-A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3 V, 5 V, 12 V, 15 V, and an adjustable output version. Requiring a minimum number of external components, these regulators are simple to use and include fault protection and a fixed-frequency oscillator. The LM2576 series offers a high-efficiency replacement for popular three-terminal linear regulators. It substantially reduces the size of the heat sink, and in some cases no heat sink is required. 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. Other features include a ±4% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. External shutdown is included, featuring 50-µA (typical) standby current. The output switch includes cycle-by-cycle current limiting, as well as thermal shutdown for full protection under fault conditions.
Features:
• 3.3-V, 5-V, 12-V, 15-V, and Adjustable Output Versions
• Adjustable Version Output Voltage Range,1.23 V to 37 V (57 V for HV Version)
±4% Maximum Over Line and Load Conditions
• Specified 3-A Output Current
• Wide Input Voltage Range: 40 V Up to 60 V for HV Version
• 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 Preregulator for Linear Regulators
• On-Card Switching Regulators
• Positive-to-Negative Converter (Buck-Boost)
