LM2576WU-TR Microchip

LM2576 Micrel, Inc. LM2576 52kHz Simple 3A Buck Regulator General Description Features The LM2576 series of monolithic integrated circuits provide 3.3V, 5V, 12V, and adjustable output versions all the active functions for a step-down (buck) switching Voltage over specified line and load conditions: regulator. Fixed versions are available with a 3.3V, 5V, or 12V Fixed version: 3% max. output voltage fixed output. Adjustable versions have an output voltage Adjustable version: 2% max. feedback voltage range from 1.23V to 37V. Both versions are capable of driving Guaranteed 3A output current a 3A load with excellent line and load regulation. Wide input voltage range: These regulators are simple to use because they require a 4V to 40V minimum number of external components and include internal Wide output voltage range frequency compensation and a fixed-frequency oscillator. 1.23V to 37V The LM2576 series offers a high efficiency replacement for Requires only 4 external components popular three-terminal adjustable linear regulators. It 52kHz fixed frequency internal oscillator substantially reduces the size of the heat sink, and in many Low power standby mode I typically < 200 A cases no heat sink is required. Q 80% efficiency (adjustable version typically > 80%) A standard series of inductors available from several different Uses readily available standard inductors manufacturers are ideal for use with the LM2576 series. This Thermal shutdown and current limit protection feature greatly simplifies the design of switch-mode power supplies. 100% electrical thermal limit burn-in The feedback voltage is guaranteed to 2% tolerance for Applications adjustable versions, and the output voltage is guaranteed to 3% for fixed versions, within specified input voltages and Simple high-efficiency step-down (buck) regulator output load conditions. The oscillator frequency is guaranteed Efficient pre-regulator for linear regulators to 10%. External shutdown is included, featuring less than On-card switching regulators 200 A standby current. The output switch includes cycle-by- Positive to negative converter (inverting Buck-Boost) cycle current limiting and thermal shutdown for full protection Isolated Flyback Converter using minimum number of under fault conditions. external components Negative Boost Converter Typical Applications 7V40V 7V40V Unregulated Unregulated +5V, 1A +5V, 1A 4 4 Feedback Feedback DC Input DC Input 1 Regulated 1 Regulated LM2575-5.0 LM2575 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 Regulator in Typical Application Adjustable Regulator in Fixed Output Application Micrel, Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 474-1000 LM2576 Micrel, Inc. Ordering Information Part Number Temperature Standard RoHS Compliant** Range Package LM2576BT* LM2576WT* 40C to +85C TO-220-5 LM2576-3.3BT LM2576-3.3WT 40C to +85C TO-220-5 LM2576-5.0BT LM2576-5.0WT 40C to +85C TO-220-5 LM2576-12BT LM2576-12WT 40C to +85C TO-220-5 LM2576BU* LM2576WU* 40C to +85C TO-263-5 LM2576-3.3BU LM2576-3.3WU 40C to +85C TO-263-5 LM2576-5.0BU LM2576-5.0WU 40C to +85C TO-263-5 LM2576-12BU LM2576-12WU 40C to +85C TO-263-5 * Adjustable output regulators. **RoHS compliant withhot-melting solde exemption. Contact factory for bent or staggered leads option. Pin Configurations 5-LEAD TO-220 (T) 5-LEAD TO-263 (U) GND GND 5- ON/OFF 5- ON/OFF 4- FEEDBACK 4- FEEDBACK 3- GROUND 3- GROUND 2- OUTPUT 2- OUTPUT 1- V 1- V IN IN M9999-082605-B 2 August 2005