LM2576R-5.0

The LM2576R-5.0 from Texas Instruments is a SIMPLE SWITCHER 3A step-down voltage regulator providing fixed 5.0V output from inputs up to 40V. It integrates all active functions including a 3A NPN power switch, oscillator, and control circuitry, requiring only an inductor, catch diode, and two capacitors. The 52kHz switching frequency allows standard inductors. Thermal shutdown and cycle-by-cycle current limiting provide robust operation. The TO-263 surface-mount package provides excellent thermal dissipation.

The LM2576R-5.0 uses fixed-frequency PWM control with a 52kHz internal oscillator. The output voltage is compared with an internal 1.23V reference. The error amplifier controls the duty cycle of the internal NPN power switch. When on, current flows from VIN through the inductor to the output, storing energy. When off, inductor current flows through the catch diode, releasing stored energy. The current limiting uses cycle-by-cycle peak current detection. Thermal shutdown disables the switch when junction temperature exceeds approximately 170°C.

• 12V/24V automotive battery to 5V conversion
• Industrial 24V bus to 5V step-down regulation
• Battery-powered instrument 5V power supply
• Embedded system 5V rail from unregulated supply
• LED strip 5V power from 12V adapter