Standalone Linear Li-Ion Battery Charger with Thermistor Input

The LTC4061-4.4 is a full-featured, flexible, standalone linear charger for single-cell 4.375V Lithium-Ion batteries. It is capable of operating within USB power specifications.

Both programmable time and programmable current based termination schemes are available. Furthermore, the CHRG open-drain status pin can be programmed to indicate the battery charge state according to the needs of the application. Additional safety features designed to maximize battery lifetime and reliability include NTC battery temperature sensing and the SmartStart charging algorithm.

No external sense resistor or external blocking diode is required for charging due to the internal MOSFET architecture. Internal thermal feedback regulates the charge current to maintain a constant die temperature during high power operation or high ambient temperature conditions. The charge current is programmed with an external resistor. With power applied, the LTC4061-4.4 can be put into shutdown mode to reduce the supply current to 20µA and the battery drain current to less than 5µA.

Other features include smart recharge, USB C/5 current programming input, undervoltage lockout and AC Present logic output.

Float Voltage (V)

LTC4061

4.2V

LTC4061-4.4

4.4V

Applications

* Handheld Computers

* Portable MP3 Players

* Digital Cameras

* Charge Current Programmable up to 1A

* Charges Single Cell Li-Ion Batteries Directly from USB Port

* Preset 4.375V Float Voltage with ±0.4% Accuracy

* Thermistor Input for Temperature Qualified Charging

* Input Supply Present Logic Output

* Thermal Regulation Maximizes Charge Rate Without Risk of Overheating