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. These regulators are simple to use because they require a minimum number of external components and include internal frequency compensation and a fixed-frequency oscillator. The LM2576 series offers a high efficiency replacement for popular three-terminal adjustable linear regulators. It substantially reduces the size of the heat sink, and in many cases no heat sink is required. A standard series of inductors available from several different manufacturers are ideal for use with the LM2576 series. This feature greatly simplifies the design of switch-mode power supplies. The feedback voltage is guaranteed to ±2% tolerance for adjustable versions, and the output voltage is guaranteed to ±3% for fixed versions, within specified input voltages and output load conditions. The oscillator frequency is guaranteed to ±10%. External shutdown is included, featuring less than 200µA standby current. The output switch includes cycle-bycycle current limiting and thermal shutdown for full protection under fault conditions.
5V output versions Voltage over specified line and load conditions: Fixed version: ±3% 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