LTC3440 Datasheet | Linear Technology

Micropower Synchronous Buck-Boost DC/DC Converter Features nn Single Inductor nn Fixed Frequency Operation with Battery Voltages Above, Below or Equal to the Output nn Synchronous Rectification: Up to 96% Efficiency nn 25µA Quiescent Current in Burst Mode® Operation nn Up to 600m A Continuous Output Current nn No Schottky Diodes Required (VOUT < 4.3V) nn VOUT Disconnected from VIN During Shutdown nn 2.5V to 5.5V Input and Output Range nn Programmable Oscillator Frequency from 300k Hz to 2MHz nn Synchronizable Oscillator nn Burst Mode Enable Control nn <1µA Shutdown Current nn Small Thermally Enhanced 10-Pin MSOP and (3mm × 3mm) DFN Packages Applications nn Palmtop puters nn Handheld Instruments nn MP3 Players nn Digital Cameras Description The LTC®3440 is a high efficiency, fixed frequency, Buck Boost DC/DC converter that operates from input voltages above, below or equal to the output voltage. The topology incorporated in the IC provides a continuous transfer function through all operating modes, making the product ideal for single lithium-ion, multicell alkaline or Ni MH applications where the output voltage is within the battery voltage range. The device includes two 0.19Ω N-channel MOSFET switches and two 0.22Ω P-channel switches. Switching frequencies up to 2MHz are programmed with an external resistor and the oscillator can be synchronized to an external clock. Quiescent current is only 25µA in Burst Mode operation, maximizing battery life in portable applications. Burst Mode operation is user controlled and can be enabled by driving the MODE/SYNC pin high. If the MODE/SYNC pin has either a clock or is driven low, then fixed frequency switching is enabled. Other Features include a 1µA shutdown, soft-start control, thermal shutdown and current limit. The LTC3440 is available in the 10-pin thermally enhanced MSOP and (3mm × 3mm) DFN packages. L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks and Thin SOT is a...