DESCRIPTION
The LTC®3454 is a synchronous buck-boost DC/DC converter optimized for driving a single high power LED at currents up to 1A from a single cell Li-Ion battery input. The regulator operates in either synchronous buck, synchronous boost, or buck-boost mode depending on input voltage and LED forward voltage. PLED/PIN effi ciency greater than 90% can be achieved over the entire usable range of a Li-Ion battery (2.7V to 4.2V).

FEATURES
■ High Effi ciency: >90% Typical in Torch Mode, >80% in Flash Mode
■ Wide VIN Range: 2.7V to 5.5V
■ Up to 1A Continuous Output Current
■ 3.5% LED Current Programming Accuracy
■ Internal Soft-Start
■ Open/Shorted LED Protection
■ Constant Frequency 1MHz Operation
■ Zero Shutdown Current
■ Overtemperature Protection
■ Small Thermally Enhanced 10-Lead (3mm × 3mm) DFN Package

APPLICATIONS
■ Cell Phone Camera Flash
■ Cell Phone Torch Lighting
■ Digital Cameras
■ PDAs
■ Misc Li-Ion LED Drivers