MIC4682 Precision Current Limit SOIC-8 SuperSwitcher Buck Regulator General Description Features The MIC4682 is an easy-to-use step-down (buck) switch- Programmable output current limit mode voltage regulator. It features a programmable 10% accuracy over temperature current limit that allows 10% current limit accuracy over its Wide 4V to 34V operating input voltage range full operating temperature range. The precision current Fixed 200kHz PWM operation limit makes the MIC4682 ideal for constant-voltage constant-current applications, such as simple battery Power SOIC-8 package allows 2A continuous output current chargers. The precision current limit also gives designers the ability to set the maximum output current below the All surface mount solution saturation current rating of the inductor. This allows the Internally compensated use of the smallest possible inductors for a given Less than 1A typical shutdown-mode current application, saving valuable space and cost. Thermal shutdown protection The MIC4682 is a very robust device. Its 4V to 34V input voltage range allows the MIC4682 to safely be used in applications where voltage transients may be present. Applications Additional protection features include cycle-by-cycle Battery chargers current limiting and over-temperature shutdown. The MIC4682 is available in a thermally optimized power White LED drivers SOIC-8 package that allows it to achieve 2A of continuous Constant voltage constant current step-down output current. converters The MIC4682 requires a minimum number of external Simple step-down regulator with precise current limit components and can operate using a standard series of USB power supplies inductors. Compensation is provided internally for fast transient response and ease of use. The MIC4682 is available in the 8-pin power SOIC with a 40C to +125C junction temperature range. Data sheets and support documentation can be found on Micrels web site at: www.micrel.com. Typical Application MIC4682 MIC4682 Current Limit L1 +7.5V to +34V 5V/1A 5 8 Characteristics IN SW 6 C1 68H R1 10F C2 3.01k 5 50V 220F 4 1 SHDN FB (x2) 10V 4 D1 R2 R3 ISET GND B240 976 10M 3 3 2, 6, 7 2 R4 16.2k 1 V =12V IN 0 0 0.5 1 1.5 2 CURRENT LIMIT (A) Constant Current/Constant Voltage Li-Ion Battery Charger SuperSwitcher is a trademark of Micrel, Inc Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC4682 Ordering Information Part Number Voltage Junction Temp. Range Package Standard Pb-Free MIC4682BM MIC4682YM Adj. 40 to +125C 8-Pin SOIC Note: Other Voltage available. Contact Micrel for details. Pin Configuration FB 1 8SW GND 2 7 GND ISET 3 6 GND SHDN 4 5 IN 8-Pin Power SOIC (M) Pin Description Pin Number Pin Name Pin Function 1 FB Feedback (Input): Output voltage sense node. Connect to 1.23V-tap of the output voltage-divider network. 2, 6, 7 GND Ground (Return): Ground. 3 ISET Current Limit Set (Input): Connect an external resistor to ground to set the current limit. Do not ground or float this pin. 4 SHDN Shutdown (Input): Logic low (<0.8V) enables regulator. Logic high (>2V) shuts down regulator. 5 IN Supply Voltage (Input): Unregulated +4V to +34V supply voltage. 8 SW Switch (Output): Internal power emitter of NPN output switch. M9999-061507 June 2007 2