GENERAL DESCRIPTION
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 XT4059 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 XT4059 automatically enters a low current state, dropping the battery drain current to less than 1uA. The XT4059 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.. 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.
