MIC4575 200kHz Simple 1A Buck Regulator General Description Features The MIC4575 is a series of easy to use fixed and Fixed 200kHz operation adjustable BiCMOS step-down (buck) switch-mode voltage 3.3V, 5V, and adjustable output versions regulators. The 200kHz MIC4575 duplicates the pinout Voltage over specified line and load conditions: and function of the 52kHz LM2575. The higher switching Fixed version: 3% max. output voltage frequency may allow up to a 2:1 reduction in output filter Adjustable version: 2% max. feedback voltage inductor size. Guaranteed 1A switch current The MIC4575 is available in 3.3V, and 5V fixed output Wide 4V to 24V input voltage range versions or a 1.23V to 20V adjustable output version. Both Wide 1.23V to 20V output voltage range versions are capable of driving a 1A load with excellent line and load regulation. Requires minimum external components < 200A typical shutdown mode The feedback voltage is guaranteed to 2% tolerance for adjustable versions, and the output voltage is guaranteed 75% efficiency (adjustable version > 75% typical) to 3% for fixed versions, within specified voltages and Standard inductors and capacitors are25% of typical load conditions. The oscillator frequency is guaranteed to LM2575 values 10%. Thermal shutdown In shutdown mode, the regulator draws less than 200A Overcurrent protection standby current. The regulator performs cycle-by-cycle 100% electrical thermal limit burn-in current limiting and thermal shutdown for protection under fault conditions. Applications This series of simple switch-mode regulators requires a minimum number of external components and can operate Simple high-efficiency step-down (buck) regulator using a standard series of inductors. Frequency comp- Efficient pre-regulator for linear regulators ensation is provided internally. On-card switching regulators The MIC4575 is available in TO-220 (T) and TO-263 (U) Positive-to-negative converter (inverting buck-boost) packages for the industrial temperature range. Battery charger Data sheets and support documentation can be found on Negative boost converter Micrels web site at www.micrel.com. Step-down 6V to 3.3V for Intel Pentium and similar microprocessors Typical Application L1 5.0V/1A Shutdown 5 2 SHDN SW Enable 68H MIC4575-5.0 T 8V to 24V 1 4 C2 V FB IN 330F C1 GND 16V D1 150F 3 1N5819 35V Fixed Regulator Adjustable Regulator Pentium is a registered trademark of Intel Corporation Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC4575 Ordering Information Part Number Standard RoHS Compliant* Voltage Temperature Range Package MIC4575-3.3BT MIC4575-3.3WT 3.3V 40 to +85C 5-Pin TO-220 MIC4575-5.0BT MIC4575-5.0WT 5.0V 40 to +85C 5-Pin TO-220 MIC4575BT MIC4575WT Adj. 40 to +85C 5-Pin TO-220 MIC4575-3.3BU MIC4575-3.3WU 3.3V 40 to +85C 5-Pin TO-263 MIC4575-5.0BU MIC4575-5.0WU 5.0V 40 to +85C 5-Pin TO-263 MIC4575BU MIC4575WU Adj. 40 to +85C 5-Pin TO-263 * RoHS compliant with high-melting solder exemption. Pin Configuration 5 SHDN 4FB 3 GND 2SW 1 VIN 5-Pin TO-220 (T) 5-Pin TO-263 (U) Pin Description Pin Number Pin Name Pin Function 1 IN Supply Voltage (Input): Unregulated +4V to +40V supply voltage. 2 SW Switch (Output): Emitter of NPN output switch. Connect to external storage inductor and Shottky diode. 3, TAB GND Ground. 4 FB Feedback (Input): Output voltage feedback to regulator. Connect to output of supply for fixed versions. Connect to 1.23V tap of resistive divider for adjustable versions. 5 SHDN Shutdown (Input): Logic low enables regulator. Logic high (> 2.4V) shuts down regulator. M9999-072909 July 2009 2 TAB