The LTC®3552 is a complete constant-current/constant voltage linear charger with a dual DC/DC converter for single cell lithium-ion batteries. Its DFN package and low external component count make the LTC3552 ideally suited for portable applications. Furthermore, the LTC3552 is designed to work within USB power specifi cations.

FEATURES
■ Programmable Charge Current Up to 950mA
■ Complete Linear Charger and Dual DC/DC Regulator
■ Buck Converter Output Voltage from 0.6V to 5V
■ No MOSFET, Sense Resistor or Blocking Diode Required
■ Thermal Regulation Maximizes Charge Rate Without Risk of Overheating*
■ Charges Directly from a USB Port
■ Programmable Charge Current Termination
■ Preset 4.2V Charge Voltage with ±1% Accuracy
■ Charge Current Monitor Output for Gas Gauging*
■ Automatic Recharge
■ Charge Status Output
■ “Power Present” Output
■ 2.9V Trickle Charge Threshold
■ Soft-Start Limits Inrush Current
■ Low Quiescent Current Buck Converter (40µA)
■ Current Mode Operation, Constant Frequency (2.25MHz)
■ Low Profi le (5mm × 3mm × 0.75mm) DFN Package

APPLICATIONS
■ Cellular Telephones, PDAs, MP3 Players
■ Bluetooth Applications