DESCRIPTION
The LTC®3427 is the industry’s first high efficiency, fixed frequency, step-up DC/DC converter with true output disconnect in a 6-lead 2mm × 2mm DFN package. Requiring minimal external components, the LTC3427 operates from an input voltage as low as 1.8V. The LTC3427 contains an internal 0.525Ω N-channel MOSFET switch and a 0.575Ω P-channel MOSFET synchronous rectifier, which enables it to supply 200mA at 3.3V from a 2-cell alkaline battery input.
The LTC3427 limits inrush current during start-up and provides a soft-start of VOUT. A switching frequency of 1.25MHz minimizes solution footprint by allowing the use of tiny, low profile inductors and ceramic capacitors and produces very low VOUT ripple. The current mode PWM design is internally compensated, reducing external parts count. Anti-ringing control reduces EMI in discontinuous mode operation. The LTC3427 also features low shutdown current of under 1µA and thermal shutdown.

FEATURES
■ High Efficiency: Up to 94%
■ 3.3V at 200mA from Two Alkaline Cells
■ 5V at 200mA from a Single Li-Ion Cell
■ Inrush Current Limiting and Soft-Start
■ Output Disconnect in Shutdown
■ 1.8V to 5V VIN Range
■ 1.8V to 5.25V VOUT Range
■ 1.25MHz Fixed Frequency, Low Noise PWM
■ Internal Synchronous Rectifier
■ Logic Controlled Shutdown (<1µA)
■ Anti-Ringing Control Minimizes EMI
■ Tiny External Components
■ Short-Circuit Protection
■ Low Profile (0.75mm × 2mm × 2mm) DFN Package

APPLICATIONS
■ Handheld Instruments
■ Digital Cameras
■ Wireless Handsets
■ GPS Receivers
■ Portable Medical Devices
■ MP3 Players