LM2575-3.3WU Microchip

LM2575 52kHz Simple 1A Buck Regulator General Description Features The LM2575 series of monolithic integrated circuits 3.3V, 5V, 12V, and adjustable output versions provide all the active functions for a step-down (buck) Voltage over specified line and load conditions: switching regulator. Fixed versions are available with a Fixed version: 3% max. output voltage 3.3V, 5V, 12V, fixed output. Adjustable versions have an Adjustable version: 2% max. feedback voltage output voltage range from 1.23V to 37V. Both versions are Guaranteed 1A output current capable of driving a 1A load with excellent line and load Wide input voltage range regulation. 4V to 40V These regulators are simple to use because they require a Wide output voltage range minimum number of external components and include internal frequency compensation and a fixed-frequency 1.23V to 37V oscillator. Requires only 4 external components The LM2575 series offers a high efficiency replacement for 52kHz fixed frequency internal oscillator popular three-terminal adjustable linear regulators. It Low power standby mode IQ typically <200A substantially reduces the size of the heat sink, and in 80% efficiency (adjustable version typically >80%) many cases no heat sink is required. Uses readily available standard inductors A standard series of inductors available from several Thermal shutdown and current limit protection different manufacturers are ideal for use with the LM2575 100% electrical thermal limit burn-in series. This feature greatly simplifies the design of switch- mode power supplies. The feedback voltage is guaranteed to 2% tolerance for Applications adjustable versions, and the output voltage is guaranteed Simple high-efficiency step-down (buck) regulator to 3% for fixed versions, within specified input voltages Efficient pre-regulator for linear regulators and output load conditions. The oscillator frequency is guaranteed to 10%. External shutdown is included, On-card switching regulators featuring less than 200A standby current. The output Positive to negative converter (inverting Buck-Boost) switch includes cycle-by-cycle current limiting and thermal Isolated flyback converter using minimum number of shutdown for full protection under fault conditions. external components Data sheets and support documentation can be found on Negative boost converter Micrels web site at www.micrel.com. Typical Applications 7V40V 7V40V Unregulated Unregulated +5V, 1A +5V, 1A 4 4 Feedback Feedback DC Input DC Input 1 Regulated 1 Regulated LM2575 LM2575-5.0 L1 L1 Output Output Output Output +V +V IN IN 2 2 330H 330H + + R2 3.09k + 3 5 + 3 5 C C IN IN Gnd On/Off Gnd On/Off D1 D1 C C OUT OUT 100F 100F R1 1k 1N5822 1N5822 330F 330F Note: Pin numbers are for TO-220 Package Note: Pin numbers are for TO-220 Package R2 V = 1.23 1 + OUT () R1 Fixed Regulation in Typical Application Adjustable Regulation in Fixed Output Application Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. LM2575 Ordering Information Part Number Pb-Free / Temperature Range Package Standard RoHS Compliant LM2575BN* Contact Factory 40 to +85C 16-Pin Plastic DIP LM2575-3.3BN Contact Factory 40 to +85C 16-Pin Plastic DIP LM2575-5.0BN LM2575-5.0YN 40 to +85C 16-Pin Plastic DIP LM2575-12BN LM2575-12YN 40 to +85C 16-Pin Plastic DIP LM2575BWM* LM2575YWM* 40 to +85C 24-Pin Wide SOIC LM2575-3.3BWM LM2575-3.3YWM 40 to +85C 24-Pin Wide SOIC LM2575-5.0BWM LM2575-5.0YWM 40 to +85C 24-Pin Wide SOIC LM2575-12BWM LM2575-12YWM 40 to +85C 24-Pin Wide SOIC LM2575BT* LM2575WT*/** 40 to +85C 5-Pin TO-220 LM2575-3.3BT LM2575-3.3WT** 40 to +85C 5-Pin TO-220 LM2575-5.0BT LM2575-5.0WT** 40 to +85C 5-Pin TO-220 LM2575-12BT LM2575-12WT** 40 to +85C 5-Pin TO-220 LM2575BU* LM2575WU*/** 40 to +85C 5-Pin TO-263 LM2575-3.3BU LM2575-3.3WU** 40 to +85C 5-Pin TO-263 LM2575-5.0BU LM2575-5.0WU** 40 to +85C 5-Pin TO-263 LM2575-12BU LM2575-12WU** 40 to +85C 5-Pin TO-263 Notes: * Adjustable output regulators. ** RoHS compliant withhigh-melting solde exemption. Contact factory for bent or staggered leads option. M9999-051209-B May 2009 2