The LM2576 series of regulators are monolithic integratedcircuits that provide all the active functions for a step-down(buck) switching regulator, capable of driving 3A load withexcellent line and load regulation. These devices are avail-able in fixed output voltages of 3.3V, 5V, 12V, 15V, and anadjustable output version.Requiring a minimum number of external components, theseregulators are simple to use and include internal frequencycompensation and a fixed-frequency oscillator.The LM2576 series offers a high-efficiency replacement forpopular three-terminal linear regulators. It substantially re-duces the size of the heat sink, and in some cases no heatsink is required.A standard series of inductors optimized for use with theLM2576 are available from several different manufacturers.This feature greatly simplifies the design of switch-modepower supplies.Other features include a guaranteed±4% tolerance on out-put voltage within specified input voltages and output loadconditions, and±10% on the oscillator frequency. Externalshutdown is included, featuring 50 μA (typical) standby cur-rent. The output switch includes cycle-by-cycle current limit-ing, as well as thermal shutdown for full protection underfault conditions.
