LTC3552-1

U U LTC3552-1 FEATURES Standalone Linear Li-Ion Battery Charger and Dual Synchronous Buck Converter DESCRIPTIO ■ Programmable Charge Current Up to 950mA ■ Complete Linear Charger and Dual DC/DC Regulator ■ Dual Fixed Outputs: 1.8V at 800mA 1.575V at 400mA ■ 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 ■ Soft-Start Limits Inrush Current ■ Low Quiescent Current Buck Converter (40µA) ■ Current Mode Operation, Constant Frequency (2.25MHz) ■ Low Profile (5mm × 3mm × 0.75mm) DFN Package U APPLICATIO S ■ Cellular Telephones, PDAs, MP3 Players ■ Bluetooth Applications The LTC®3552-1 is a complete constant-current/constantvoltage linear charger and dual fixed output DC/DC converter for single cell lithium-ion batteries. Its DFN package and low external component count make the LTC3552-1 ideally suited for portable applications. Furthermore, the LTC3552-1 is designed to work within USB power specifications. No external sense resistor or external blocking diode are required due to the internal MOSFET architecture. The charge voltage is fixed at 4.2V and the charge current is programmed with a resistor. The charge cycle terminates when the charge current drops below the ...