LTC4007 Datasheet | Linear Technology

4A, High Efficiency, Standalone Li-Ion Battery Charger Features DESCRIPTION n plete Charger Controller for 3- or 4-Cell Lithium-Ion Batteries n High Conversion Efficiency: Up to 96% n Output Currents Exceeding 4A n ±0.8% Charging Voltage Accuracy n Built-In Charge Termination for Li-Ion Batteries n AC Adapter Current Limiting Maximizes Charge Rate- n Thermistor Input for Temperature Qualified Charging n Wide Input Voltage Range: 6V to 28V n 0.5V Dropout Voltage; Maximum Duty Cycle: 98% n Programmable Charge Current: ±4% Accuracy n Indicator Outputs for Charging, C/10 Current Detection, AC Adapter Present, Low Battery, Input Current Limiting and Faults n Charging Current Monitor Output n Available in a 24-Pin Narrow SSOP Package APPLICATIONS n Notebook puters n Portable Instruments n Battery-Backup Systems n Standalone Li-Ion Chargers The LTC®4007 is a plete constant-current/constant-voltage charger controller for 3- or 4-cell lithium-ion batteries. The PWM controller uses a synchronous, quasi-constant frequency, constant off-time architecture that will not generate audible noise even when using ceramic capacitors. Charging current is programmable to ±4% accuracy using a programming resistor. Charging current can also be monitored as a voltage across the programming resistor. The output float voltage is pin programmed for cell count (3 cells or 4 cells) and chemistry (4.2V/4.1V). A timer, programmed by an external resistor, sets the charge termination time. Charging is automatically restarted when cell voltage falls below 3.9V/cell. LTC4007 includes a thermistor input, which suspends charging if an unsafe temperature condition is detected. If the cell voltage is less than 2.5V, a low-battery indicator asserts and can be used to program a trickle charge current to safely charge depleted batteries. The FAULT pin is also asserted and charging terminates if the low-battery condition persists for more than 1/4 of the total charge...