DESCRIPTION

The A4055 is a complete constant-current / constant-voltage linear charger for single cell lithium-Ion batteries. No external sense resistor is needed, and no blocking diode is required due to the internal MOSFET architecture. Thermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient temperature. The charge voltage is fixed at 4.2V, and the charge current can be programmed externally with a single resistor. The A4055 automatically terminates the charge cycle when the charge current drops to 1/10 the programmed value after the final float voltage is reached. When the input supply (wall adapter or USB supply) is removed, the A4055 automatically enters a low current state, dropping the battery drain current to less than 2μA. The A4055 can be put into shutdown mode, reducing the supply current to 25μA. Other features include charge current monitor, under-voltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage. The A4055 is available in SOT-25 Package

FEATURES

 Programmable Charge Current Up to 800mA

 No MOSFET, Sense Resistor or Blocking Diode Required

 Preset 4.2V Charge Voltage with ±1 Accuracy

 Charge Current Monitor Output for Gas Gauging

 Thermal Regulation Maximizes Charge Rate Without Risk of Overheating

 Charges Single Cell Li-Ion Batteries directly from USB Port

 Over-Voltage Protect

 Automatic Recharge

 Charge Status Output Pin

 C/10 Charge Termination

 25μA Supply Current in Shutdown

 2.9V Trickle Charge Threshold

 Soft-Start Limits Inrush Current

 Available in SOT-25 Package APPLICATION

 Cellular and Smart Phones

 Charging Docks and Cradles

 Blue Tooth Applications

 PDAs

 MP3/MP4/MP5 Players