MIC2141 Micropower Boost Converter General Description Features The MIC2141 is a micropower boost switching regulator Implements low-power boost, SEPIC, or flyback that can operate from 3- or 4-cell nickel-metal-hydride 2.2V to 14V input voltage batteries or a single Li-ion cell. This regulator employs a 330kHz switching frequency constant 330kHz, fixed 18% duty-cycle, gated-oscillator <2A shutdown current architecture. 70A quiescent current The MIC2141 can be used in applications where the output voltage must be dynamically adjusted. The device 1.24V bandgap reference features a control signal input which is used to Typical output current 1mA to 10mA proportionally adjust the output voltage. The control signal SOT23-5 package input has a gain of 6, allowing a 0.8V to 3.6V control signal to vary a 4.8V to 22V output. Applications The MIC2141 requires only three external components to operate and is available in a tiny 5-pin SOT-23 package for LCD bias supply space and power-sensitive portable applications. The CCD digital camera supply MIC2141 draws only 70A of quiescent current and can operate with an efficiency exceeding 85%. Data sheets and support documentation can be found on Micrels web site at: www.micrel.com. Typical Application Control Voltage 10H vs. Output Voltage Variable 4.0 V * V C OUT (from DAC) 3.5 MIC2141 3.0 15 2.5 2 2.0 34 1.5 10F 1.0 0.5 0 0 5 10 15 20 25 V (V) OUT DAC-Controlled LCD Bias Voltage Supply Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC2141 Ordering Information Part Number Marking* Ambient Voltage Package Temperature Range Standard Pb-Free Standard Pb-Free MIC2141BM5 MIC2141YM5 SAAA SAAA Adj. 40 to +85C 5-Pin SOT23 * Under bar symbol ( ) may not be to scale. Pin Configuration 5-Pin SOT23 (BM5) 5-Pin SOT23 (YM5) Pin Description Pin Number Pin Name Pin Function 1 IN Input: +2.5V to +14V supply for internal circuity. 2 GND Ground: Return for internal circuitry and internal MOSFET (switch) source. 3 SW Switch Node (Input): Internal MOSFET drain 22V maximum. 4 FB Feedback (Input): Output voltage sense node. Compared to VC control input voltage. 5 VC Control (Input): Output voltage control signal input. Input voltage of 0.8V to3.6V is proportional to 4.8V to 22V output voltage (gain of 6). If the pin is not connected, the output voltage will be V 0.5V. IN M9999-122006 December 2006 2