The KF5056 is a complete constant current & constantvoltage linear charger for single cell lithium-ion batteries.Its SOP/MSOP package and low external componentcount make the KF5056 ideally suited for portableapplications. Furthermore, the KF5056 is specificallydesigned to work within USB power specifications.No external sense resistor is needed, and no blockingdiode is required due to the internal MOSFETarchitecture. Thermal feedback regulates the chargecurrent to limit the die temperature during high poweroperation or high ambient temperature. The chargevoltage is fixed at 4.2V, and the charge current can beprogrammed externally with a single resistor. TheKF5056 automatically terminates the charge cycle whenthe charge current drops to 1/10th the programmed valueafter the final float voltage is reached.When the input supply (wall adapter or USB supply) isremoved, the KF5056 automatically enters a low currentstate, dropping the battery drain current to less than 2uA.The KF5056 can be put into shutdown mode, reducingthe supply current to 50uA.Other features include Battery temperature monitor,under-voltage lockout, automatic recharge and two statuspins to indicate charge and charge termination.