The LTC4002 is a complete battery charger controller for one (4.2V) or two (8.4V) cell lithium-ion batteries. With a 500kHz switching frequency, the LTC4002 provides a small, simple and efficient solution to fast charge Li-Ion batteries from a wide range of supply voltages. An external sense resistor sets the charge current with ±5% accuracy. An internal resistor divider and precision reference set the final float voltage to 4.2V per cell with ±1% accuracy.When the input supply is removed, the LTC4002 automatically enters a low current sleep mode, dropping the battery drain current to 10µA. An internal comparator detects the near end-of-charge condition while an internal timer sets the total charge time and terminates the charge cycle. After the charge cycle ends, if the battery voltage drops below 4.05V per cell, a new charge cycle will automatically begin.The LTC4002 is available in the 8-lead SO and 10-lead DFN packages.ApplicationsPortable ComputersCharging DocksHandheld Instruments