MICROCHIP LM2574-3.3BWM

The LM2574 family is a series of easy to use fixed and adjustable switching voltage regulators. The LM2574 contains all of the active circuitry necessary to construct a stepdown (buck) switching regulator and requires a minimum of external components. The LM2574 is available in 3.3V, 5V, and 12V fixed output versions, or an adjustable version with an output voltage range of 1.23V to 37V. Output voltage is guaranteed to ±4% for specified input and load conditions. The LM2574 can supply 0.5A while maintaining excellent line and load regulation. The output switch includes cycle-bycycle current limiting, as well as thermal shutdown for full protection under fault conditions. An external shutdown connection selects operating or standby modes. Standby current is less than 200μA. Heat sinks are generally unnecessary due the regulator’s high efficiency. Adequate heat transfer is usually provided by soldering all package pins to a printed circuit board. The LM2574 includes internal frequency compensation and an internal 52kHz fixed frequency oscillator guaranteed to ±10% of the frequency. Circuits constructed around the LM2574 use a standard series of inductors which are available from several different manufacturers.

• 3.3V, 5V, 12V, and Adjustable Output Versions
• Adjustable Version Output 1.23V to 37V ±4% Max. over Line and Load Conditions.
• Guaranteed 0.5A Output Current
• Wide Input Voltage, up to 40V
• Thermal Shutdown and Current Limit Protection
• Requires only 4 external Components.
• Shutdown Capability (Standby Mode)
• Low Power Standby Mode <200μA Typical
• High Efficiency
• 52kHz Fixed Frequency Internal Oscillator
• Uses Standard Inductors

• Simple High-efficiency Step-down (Buck) Regulator
• Efficient Pre-Regulator for Linear Regulators
• On-card Switching Regulators
• Positive to Negative Converter (Buck-Boost)