LTC4008

LTC4008 4A, High Efficiency, Multi-Chemistry Battery Charger FEATURES n General Purpose Charger Controller n High Conversion Efficiency: Up to 96% n Output Currents Exceeding 4A n ±0.8% Voltage Accuracy n AC Adapter Current Limiting Maximizes Charge Rate* n Thermistor Input for Temperature Qualified Charging n Wide Input Voltage Range: 6V to 28V n Wide Output Voltage: 3V 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, Input Current Limiting and Faults n Charging Current Monitor Output n Available in a 20-Pin Narrow SSOP Package APPLICATIONS n Notebook Computers n Portable Instruments n Battery Backup Systems DESCRIPTION The LTC®4008 is a constant-current/constant-voltage charger controller. 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 with a sense resistor and programming resistor to ±4% typical accuracy. Charging current can be monitored as a voltage across the programming resistor. An external resistor divider and precision internal reference set the final float voltage. The LTC4008 includes a thermistor sensor input that will suspend charging if an unsafe temperature condition is detected and will automatically resume charging when battery temperature returns to within safe limits; a FAULT ...