DESCRIPTION
The LTC®3542-1 is a high efficiency, fi xed output voltage of 2.8V, monolithic synchronous buck converter using a constant frequency, current mode architecture. Supply current during operation is only 26μA, dropping to <1μA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3542-1 ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems. Internal power switches are optimized to provide high efficiency and eliminate the need for an external Schottky diode.

FEATURES
■ High Effi ciency: Up to 96%
■ Fixed Output Voltage: 2.8V
■ High Peak Switch Current: 1000mA
■ Low Output Ripple (<20mVP-P Typical)
   Burst Mode Operation
■ Very Low Quiescent Current: Only 26μA
■ 2.5V to 5.5V Input Voltage Range
■ 2.25MHz Constant Frequency Operation
■ 1MHz to 3MHz External Frequency Synchronization
■ Low Dropout Operation: 100% Duty Cycle
■ No Schottky Diode Required
■ Internal Soft-Start Limits Inrush Current
■ Shutdown Mode Draws <1μA Supply Current
■ ±2% Output Voltage Accuracy
■ Current Mode Operation for Excellent Line and Load
   Transient Response
■ Overtemperature Protected
■ Available in 6-Lead 2mm × 2mm DFN

APPLICATIONS
■ Cellular Telephones
■ Wireless and DSL Modems
■ Digital Cameras
■ MP3 Players
■ PDAs and Other Handheld Devices