is a complete constant-current/constant

　　voltage linear charger for single cell lithium-ionbatteries. Furthermore the 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

　　PMOSFET 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 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 automatically enters a low

　　current state dropping the battery drain current to less

　　than 2μA.The can be put into shutdown

　　mode reducing the supply current to 55μA.Other features include charge current monitor，

　　undervoltage lockout， automatic recharge and a

　　status.LY3085A