The LTC4053 is a standalone linear charger for lithium-ion batteries that can be powered directly from a USB port. The IC contains an on-chip power MOSFET and eliminates the need for an external sense resistor and blocking diode. Thermal regulation automatically adjusts charge current to limit die temperature during high power or high ambient temperature conditions. This feature protects the end product and the LTC4053 from thermal stress while the IC charges the battery at maximum rate without interruption.The charge current and charge time can be set externally with a single resistor and capacitor, respectively. When the input supply (wall adapter or USB supply) is removed, the LTC4053 automatically enters a low current sleep mode, dropping the battery drain current to less than 5µA.The LTC4053 also includes NTC temperature sensing, C/10 detection circuitry, AC present logic, low battery charge conditioning (trickle charging) and shutdown (25µA supply current).The LTC4053 is available in a 10-pin thermally enhanced MSOP package.ApplicationsCellular TelephonesHandheld ComputersCharging Docks and CradlesMP3 PlayersDigital Cameras