General Description
The AP5057 is a complete constant current & constant
voltage linear charger for single cell lithium-ion batteries.
Its SOP package and low external component count
make the AP5057 ideally suited for portable applications.
Furthermore, the AP5057 is specifically designed to
work within USB power specifications.
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
AP5057 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 AP5057 automatically enters a low current
state, dropping the battery drain current to less than 2uA.
The AP5057 can be put into shutdown mode, reducing
the supply current to 50uA.
Other features include Battery temperature monitor,
under-voltage lockout, automatic recharge and two status
pins to indicate charge and charge termination.

Features
Programmable Charge Current Up to 1000mA
No MOSFET, Sense Resistor or Blocking Diode
Required
Complete Linear Charger in SOP 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 Batteries Directly from
USB Port
Preset 4.2V Charge Voltage
Charge Current Monitor Output for Gas Gauging
Automatic Recharge
Charge state pairs of output, no battery and fault
status display
C/10 Charge Termination
50uA Supply Current in Shutdown
2.9V Trickle Charge Threshold
Soft-Start Limits Inrush Current
Battery temperature monitoring function
Available in SOP8-PP Package