DESCRIPTION
The LTC®3542 is a high efficiency 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 ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems. The output voltage is adjustable from 0.6V to VIN. Internal power switches are optimized to provide high effi ciency and eliminate the need for an external Schottky diode.

FEATURES
■ High Efficiency: Up to 96%
■ High Peak Switch Current: 1000mA
■ Low Output Ripple (<20mVP-P Typical)
Burst Mode Operation: Only 26µA
■ 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
■ 0.6V Reference Allows Low Output Voltages
■ 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 and Small TSOT

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