LTC3539/LTC3539-2 2A, 1MHz/2MHz Synchronous Step-Up DC/DC Converters FEATURESDESCRIPTION n Delivers 3.3V at 900mA From 2 Alkaline/NiMH Cells The LTC®3539/LTC3539-2 are synchronous, 2A step-up n Delivers 5V at 900mA From a Lithium-Polymer DC/DC converters with output disconnect. Synchronous Battery rectification enables high efficiency in the low profile n VIN Start-Up Voltage: 700mV 2mm × 3mm DFN package. Battery life is extended with n 1.5V to 5.25V VOUT Range a 700mV start-up voltage and operation down to 500mV n Up to 94% Efficiency once started. n VIN > VOUT Operation A switching frequency of 1MHz (LTC3539) or 2MHz n ±1.5% Feedback Voltage Tolerance (LTC3539-2) minimizes solution footprint by allowing the n 1MHz (LTC3539) or 2MHz (LTC3539-2) Fixed use of tiny, low profile inductors and ceramic capacitors. Frequency Operation The current mode PWM design is internally compensated, n Output Disconnect reducing external parts count. The LTC3539/LTC3539-2 n Selectable Burst Mode® or PWM Operation feature a pin-enabled automatic Burst Mode operation at n 10µA Quiescent Current light load conditions. Anti-ring circuitry reduces EMI by n Logic Controlled Shutdown: <1µA damping the inductor in discontinuous mode. Additional n Requires Only 6 External Components features include a low shutdown current of under 1µA and n Low Profile (2mm × 3mm × 0.75mm) DFN Package thermal overload protection. APPLICATIONS The LTC3539/LTC3539-2 are offered in a 2mm × 3mm × n 0.75mm DFN package. Medical Instruments n Portable Bar Code Scanners L, LT, LTC, LTM and Burst Mode are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Noise Canceling Headphones n Portable GPS Navigation n Handheld PCs TYPICAL APPLICATIONWide VIN, High Power 3.3V RegulatorEfficiency and Power Loss vs Load Current 100 1000 4.7µH V 90 IN 1.8V TO 3.6V 2.2µF 80 EFFICIENCY 100 POWER LOSS (mW) VIN SW 70 LTC3539 60 V V OUT PWM BURST MODE V 50 IN = 2.4V 10 OUT 3.3V VOUT = 3.3V 600mA 1M 33pF 40 EFFICIENCY (%) POWER LOSS 30 OFF ON SHDN FB 22µF 1 × 2 20 GND PGND 562k 10 FREQUENCY = 1MHz FREQUENCY = 2MHz 3539 TA01a 0 0.1 0.1 1 10 100 1000 ILOAD AVERAGE (mA) 3539 TA01b 35392fc For more information www.linear.com/3539/3539-2 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Related Parts
