DESCRIPTION
The LTC®1732 is a complete constant-current/constant-voltage linear charge controller for lithium-ion (Li-Ion) batteries. Nickel-cadmium (NiCd) and nickel metal-hydride (NiMH) batteries can also be charged with constant current using external termination. Charge current can be programmed with 7% (max) accuracy using external sense and program resistors. An internal resistor divider and precision reference set the final float voltage with 1% accuracy. The SEL pin allows users to charge either 4.1V or 4.2V cells.

FEATURES
■ Complete Linear Charger Controller for 1-Cell
   Lithium-Ion Batteries
■ Preset Charge Voltage with 1% Accuracy
■ 4.5V to 12V Input Voltage Range
■ Programmable Charge Current
■ C/10 Charge Current Detection Output
■ Programmable Charge Termination Timer
■ Small, Thin 10-Pin MSOP Package
■ Select Pin to Charge Either 4.1V or
   4.2V Cells (LTC1732-4)
■ Automatic Sleep Mode When Input Supply
   is Removed (Only 7µA Battery Drain)
■ Automatic Trickle Charge of Low Voltage Cells
■ Programmable for Constant-Current-Only Mode
■ Battery Insertion Detect and Automatic Charging
   of Low-Battery Cell
■ Input Supply (Wall Adapter) Detection Output
■ 4.05V Recharge Threshold for 4.2V Cells
   (LTC1732-4.2)
■ 3.8V Recharge Threshold for 4.1V or 4.2V Cells
   (LTC1732-4)

APPLICATIONS
■ Cellular Phones
■ Handheld Computers
■ Charging Docks and Cradles