DESCRIPTION
The LTC®4007 is a complete constant-current/constant-voltage charger controller for 3- or 4-cell lithium-ion batteries. The PWM controller uses a synchronous, quasiconstant frequency, constant off-time architecture that will not generate audible noise even when using ceramic capacitors. Charging current is programmable to ±5% accuracy using a programming resistor. Charging current can also be monitored as a voltage across the programming resistor.

FEATURES
■ Complete Charger Controller for 3- or 4-Cell
   Lithium-Ion Batteries
■ High Conversion Efficiency: Up to 96%
■ Output Currents Exceeding 4A
■ ±0.8% Charging Voltage Accuracy
■ Built-In Charge Termination for Li-Ion Batteries
■ AC Adapter Current Limiting Maximizes Charge Rate*
■ Thermistor Input for Temperature Qualified Charging
■ Wide Input Voltage Range: 6V to 28V
■ 0.5V Dropout Voltage; Maximum Duty Cycle: 98%
■ Programmable Charge Current: ±4% Accuracy
■ Indicator Outputs for Charging, C/10 Current
   Detection, AC Adapter Present, Low Battery, Input
   Current Limiting and Faults
■ Charging Current Monitor Output
■ Available in a 24-Pin Narrow SSOP Package

APPLICATIONS
■ Notebook Computers
■ Portable Instruments
■ Battery-Backup Systems
■ Standalone Li-Ion Chargers