The LTC4065L is a complete constant-current/constant-voltage linear charger for single-cell lithium-ion batteries. Its small size and ability to accurately regulate low charge currents make the LTC4065L especially well-suited for portable applications using low capacity rechargeable lithium-ion cells. Furthermore, LTC4065L is specifically designed to work within USB power specifications.TheCHRGpin indicates when charge current has dropped to ten percent of its programmed value (C/10). An internal timer terminates charging according to battery manufacturer specifications.The LTC4065L-4.1/LTC4065LX-4.1 features a constant-voltage float voltage of 4.1V. This 4.1V version of the standard LTC4065L/LTC4065LX is intended for back-up or high ambient temperature applications. Under these conditions, a reduced float voltage will trade-off initial cell capacity for the benefit of increased capacity retention over the life of the battery. A reduced float voltage also minimizes swelling in prismatic and polymer cells.When the input supply (wall adapter or USB supply) is removed, the LTC4065L automatically enters a low current state, dropping battery drain current to less than 1µA. With power applied, LTC4065L can be put into shutdown mode, reducing the supply current to less than 20µA.The full-featured LTC4065L also includes automatic recharge, low-battery charge conditioning (trickle charging) and soft-start (to limit inrush current).Float Voltage (V)Charge Current RangePin 5 Is EN or ACPR?Trickle Charge?LTC40654.2V40mA to 750mAENYesLTC4065A4.2V40mA to 750mAACPRYesLTC4065-4.44.4V40mA to 750mAENYesLTC4065L4.2V8mA to 250mAENYesLTC4065LX4.2V8mA to 250mAENNoLTC4065L-4.14.1V8mA to 250mAENYesApplicationsCharger for Li-Ion Coin Cell BatteriesPortable MP3 Players, Wireless HeadsetsBluetooth ApplicationsMultifunction Wristwatches