MIC2145 Micrel, Inc. MIC2145 High Efficiency 2.5W Boost Converter General Description Features The MIC2145 is a small size boost switching regulator that 2.4V to 16V input voltage can provide over 2.5W of output power. The input voltage Output adjustable to 16V range is between 2.4V to 16V, making the device suitable for Programmable peak current limit one-cell Li-Ion and 3- to 4-cell alkaline/NiCad/NiMH applica- Soft start tions. The output voltage of the MIC2145 can be adjusted up Up to 450kHz switching frequency to 16V. 0.5A shutdown current 200A quiescent current The MIC2145 is well suited for portable, space-sensitive Capable of 5V/ 500mA output with 3.3V input applications. Its typical 450kHz operation allows small sur- Achieves over 85% efficiency face mount external components to be used. The MIC2145 Implements low power BOOST, SEPIC, and FLYBACK has a low quiescent current of 200A, and a typical shutdown topologies current of 0.5A. The MIC2145 is capable of high efficiencies MSOP-8 and 3mm3mm MLF-10L in a small board area. Applications The MIC2145 features a low-on resistance internal switch that allows it to provide over 2.5W of output power. The peak Flash LED driver switch current can be programmed through an external LCD bias supply resistor. This allows the user to set the peak switch current at White LED driver the level where maximum efficiency occurs. It also allows the DSL bias supply user to further optimize for efficiency and inductor size by Local 3V to 5V conversion setting the peak current below the level of inductor saturation. The MIC2145 is available in an MSOP-8 and 3mm3mm MLF-10L package with an ambient operating temperature range from 40C to +85C. Ordering Information Part Number Voltage Ambient Standard Pb-Free Temp. Range Package MIC2145BMM MIC2145YMM Adj 40C to +85C 8-lead MSOP MIC2145BML MIC2145YML Adj 40C to +85C 10-lead MLF Typical Application L1 10V Output V IN Efficiency 3.0V to 5.0V 10H 90 D1 C IN 15 V OUT 10F/6.3V 85 EN SW 10V/150mA 4 6 80 PGND VDD COUT MIC2145BMM 10F/16V 75 3 7 FB RSET 70 2 8 SS SGND 65 V = 3.0V IN 60 I Limit 10 100 1000 OUTPUT CURRENT (mA) Adjustable Output Boost Converter with Programmable Peak Switch Current MLF and MicroLeadFrame are trademarks of Amkor Technologies, Inc. Micrel, Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 474-1000 MIC2145 Micrel, Inc. Pin Configuration EN 1 10 SGND EN 1 8 SGND SS 2 FB 9 SS 2 7 FB RSET 3 8 VDD RSET 3 6 VDD PGND 4 7 SW 56 PGND SW PGND 4 5 SW 3mm3mm MLF-10L (ML) 8-Lead MSOP (MM) Pin Description Pin Number Pin Number Pin Name Pin Function MSOP MLF 11 EN Enable (Input): Logic high (1.5V) enables regulator. Logic low ( 0.7V) shuts down regulator. Do not float. 22 SS Soft Start Capacitor (External Component): Connect external capacitor to ground to control the rise time of the output voltage. 33 RSET Current Limit (External Component): Sets peak current limit of the internal power MOSFET using an external resistor. 4 4, 5 PGND Power Ground (Return): Internal power MOSFET source. 5 6, 7 SW Switch Node (Input): Internal power MOSFET drain. 68 VDD Supply (Input): +2.4V to +16V for internal circuitry. 79 FB Feedback (Input): Output voltage sense node. 810 SGND Small Signal Ground (Return): Ground M9999-042205 2 April 2005