DESCRIPTION
The A4056B is a complete constant-current /constant-voltage linear charger for single cell lithium-ion batteries. Its SOT package and low external component count make the A4056B ideally suited for portable applications especially in USB power specifications.
Internal MOSFET architecture makes A4056B no external sense resistor needed, and no blocking diode is required. 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 A4056B automatically terminates the charge cycle when the charge current drops to 1/10th the programmed value after the final float voltage is reached.
When the input supply (wall adapter or USB supply) is removed, the A4056B automatically enters a low current state, dropping the battery drain current to less than 2μA. The A4056B can be put into shutdown mode, reducing the supply current to 25μA.
When battery reversed, the internal protected the BAT pin throughout about 0.7mA current from GND. Also, The BAT pin has a 7KV ESD (HBM) capability.
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 A4056B is available in SOT 2 5 and SOT89 5
packages.

FEATURES
 Programmable Charge Current Up to 500mA
 No MOSFET, Sense Resistor o r Blocking Diode
Required
 Complete Linear Charger in SOT Package for
single Cell Lithium Ion Batteries
 Constant Current/Constant Voltage Operation
with Thermal Regulation to Maximize Charge
Rate Without Risk of Overheating
 Charges Single Cell Li Ion Bat teries Directly
from USB Port
 Preset 4.2V Charge Voltage with ±1% Accuracy
 Charge Current Monitor Output for Gas Gauging
 Automatic Recharge
 Charge Status Output Pin
 C/10 Charge Termination
 25 μ A Supply Current in Shutdown
 2.9V Trickle Charge Threshold
 Soft Start Limits Inrush Current
 Battery reversed protection
 7KV ESD(HBM) capability
 Available in SOT 2 5 and SOT89 5 p ackage s

APPLICATION
 Cellular Telephones, PDAs, MP3 Players
 Charging Docks and Cradles
 Bluetooth Applications