LTC4008 - 4A, High Efficiency, Multi-Chemistry Battery Charger

The LTC4008 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 pin indicates this condition. A FLAG pin indicates when charging current has decreased below 10% of the programmed current. An external sense resistor programs AC adapter current limiting. The ICL pin indicates when the charging current is being reduced by input current limiting so that the charging algorithm can adapt.

Features
  • General Purpose Charger Controller
  • High Conversion Efficiency: Up to 96%
  • Output Currents Exceeding 4A
  • ±0.8% Voltage Accuracy
  • AC Adapter Current Limiting Maximizes Charge Rate*
  • Thermistor Input for Temperature Qualified Charging
  • Wide Input Voltage Range: 6V to 28V
  • Wide Output Voltage: 3V 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, Input Current Limiting and Faults
  • Charging Current Monitor Output
  • Available in a 20-Pin Narrow SSOP Package
Typical Application
Applications
  • Notebook Computers
  • Portable Instruments
  • Battery Backup Systems
Packaging

Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LTC4008EGN-1#PBFSSOP-20E$5.27$3.70
LTC4008EGN-1#TRPBFSSOP-20E$3.80
LTC4008EGN#PBFSSOP-20E$5.27$3.70
LTC4008EGN#TRPBFSSOP-20E$3.80
Datasheet
Reliability Data
LT Journal
Related Product
LTC4008 - 4A, High Efficiency, Multi-Chemistry Battery Charger
LTC4008 Package Drawing LTC4008
R480 Reliability Data
Mar 2003 Next Generation No Compromise Battery Chargers
September 2008 - Feature-Packed Charger Handles All Battery Chemistries and Produces 3A/50W for Fast Charging from a 4mm × 4mm QFN
LTC4008 Footprints and Symbols