DESCRIPTION
The LTC®4002 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.

FEATURES
■ Wide Input Supply Range:
   4.7V to 22V – 4.2 Version
   8.9V to 22V – 8.4 Version
■ High Efficiency Current Mode PWM Controller with 500kHz Switching Frequency
■ ±1% Charge Voltage Accuracy
■ End-of-Charge Current Detection Output
■ 3 Hour Charge Termination Timer
■ Constant Switching Frequency for Minimum Noise
■ ±5% Charge Current Accuracy
■ Low 10µA Reverse Battery Drain Current
■ Automatic Battery Recharge
■ Automatic Shutdown When Input Supply is Removed
■ Automatic Trickle Charging of Low Voltage Batteries
■ Battery Temperature Sensing and Charge Qualification
■ Stable with Ceramic Output Capacitor
■ 8-Lead SO and 10-Lead DFN Packages

APPLICATIONS
■ Portable Computers
■ Charging Docks
■ Handheld Instruments