felt LM2574 and LM2574HV 0.5A Step-Down Voltage Regulator Preliminary Information General Description The LM2574 family is a series of easy to use fixed and adjustable switching voltage requlators. The LM2574 con- tains all of the active circuitry necessary to construct a step- down (buck) switching regulator and requires a minimum of external components. The M2574 is available in 3.3V, 5V, 12V. and 15V fixed output versions, or an adjustable version with an output voltage range of 1.2V to 58V. 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- by-cycle 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 200uA. 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 guaran- Features * 3.3V, 5V, 12V, 15V, and Adjustable Output Versions Adjustable Version Output 1.2V to 37V (57V for MIC2574HV) +4% Max. over Line and Load Condi- tions. * Guaranteed 0.5A Output Current Wide Input Voitage, up to 57V for HV Version. * Thermal Shutdown and Current Limit Protection Requires only 4 External Components. Shutdown Capability (Standby Mode) Low Power Standby Mode < 200nA Typical. High Efficiency 52kHz Fixed Frequency Internal Oscillator Uses Standard Inductors Applications Simpte High-efficiency Step-down (Buck) Regulator Efficient Pre-Regulator for Linear Regulators On-card Switching Regulators Positive to Negative Converter (Buck-Boost) Ordering Information teed to +10% of the frequency. Part Number Temp. Range Package Circuits constructed around the LM2574 use a standard LM2574BN 40C to +85C |} 8-pin Plastic DIP series of inductors which are available from several differ- LM2574BWM 40C to +85C | 14-pin Wide SOIC ent manufacturers. LM2574-3.3BN 40C to +85C 8-pin Plastic DIP Tvpical Applicati LM2574-3.3BWM -40C to +85C | 14-pin Wide SOIC ypical Application LM2574-5.0BN -40C to +85C | 8-pin Plastic DIP cov MAX LM2574-5.0BWM -40C to +85C | 14-pin Wide SOIC UNREGULATED Fb LM2574-12BN 40C to +85C 8-pin Plastic DiP DC IN REGULATED 7 - in M2574 Le OUTPUT LM2574-12BWM 40C to +85C =| 14-pin Wide SOIC LM2574HV 330pH our wf O54 LM2574-15BN -40C to +85C | 8-pin Plastic DIP sees [eno Gum OFF to LM2574-15BWM 40C to +85C | 14-pin Wide SOIC Di ut 5 _ ; Prya0s ) aso LM2574HVBN -40C to +85C | 8-pin Plastic DIP L tit L L LM2574HVBWM -40C to +85C | 14-pin Wide SOIC - ~ ~ LM2574HV-5.0BN | -40C to +85C | 8-pin Plastic DIP Fixed Output Regulator Circuit Pin Configuration LM2574HV-5.0BWM ~40C to +85C 14-pin Wide SOIC LM2574HV-12BN 40C to +85C 8-pin Plastic DIP LM2574HV-12BWM 40C to +85C 14-pin Wide SOIC LM2574HV-15BN -40C to +85C 8-pin Plastic DIP LM2574HV-15BWM_ | 40C to +85C 14-pin Wide SOIC ret p18 * icq VV 14 * 7 * 2c 13 SIG GND 2 P}7 OUTPUT FB 34 i112 OUTPUT . SIGGND 4 (4 M7111 * orr 3[ LJ 6 OFF 54 F710 Vin PWRGND 4 5 Vi PWRGND 6 C~ FI 9 * q Ne NC: solder to printed circuit for 7c 8 . maximum heat transfer . 8-pin DIP (N) 14-pin SOIC (WM) 6-95