General Description
The LM2576 series of monolithic integrated circuits provide all the active functions for a step-down (buck) switching regulator. Fixed versions are available with a 3.3V, 5V, or 12V fixed output. Adjustable versions have an output voltage range from 1.23V to 37V. Both versions are capable of driving a 3A load with excellent line and load regulation.
   
Features
• 3.3V, 5V, 12V, and adjustable output versions
• Voltage over specified line and load conditions:
    Fixed version: ±3% max. output voltage
    Adjustable version: ±2% max. feedback voltage
• Guaranteed 3A output current
• Wide input voltage range:
    4V to 40V
• Wide output voltage range
    1.23V to 37V
• Requires only 4 external components
• 52kHz fixed frequency internal oscillator
• Low power standby mode IQ typically < 200µA
• 80% efficiency (adjustable version typically > 80%)
• Uses readily available standard inductors
• Thermal shutdown and current limit protection
• 100% electrical thermal limit burn-in
   
Applications
• Simple high-efficiency step-down (buck) regulator
• Efficient pre-regulator for linear regulators
• On-card switching regulators
• Positive to negative converter (inverting Buck-Boost)
• Isolated Flyback Converter using minimum number of
    external components
• Negative Boost Converter