LM2576xx Series SIMPLE SWITCHER Voltage Regulator

UMW's LM2576xx series regulators are monolithic integrated circuits that provide the active functions for a step-down (buck) switching regulator, capable of driving a 3 A load with excellent line and load regulation. These devices are available in fixed output voltages including 3.3 V, 5 V, 12 V, and an adjustable. Requiring a minimum number of external components, these regulators are simple to use including internal frequency compensation and a fixed-frequency oscillator.

The LM2576xx series offers a high-efficiency replacement for 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 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode power supplies. Other features include a guaranteed ±4% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. The external shutdown is included, featuring a 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.