LTC4065L Standalone 250mA Li-Ion Battery Charger in 2 × 2 DFN

Product Details

The LTC4065L is a complete constant-current/constant-voltage linear charger for single-cell lithium-ion batteries. Its small size and ability to accurately regulate low charge currents make the LTC4065L especially well-suited for portable applications using low capacity rechargeable lithium-ion cells. Furthermore, LTC4065L is specifically designed to work within USB power specifications.

The CHRG pin indicates when charge current has dropped to ten percent of its programmed value (C/10). An internal timer terminates charging according to battery manufacturer specifications.

The LTC4065L-4.1/LTC4065LX-4.1 features a constant-voltage float voltage of 4.1V. This 4.1V version of the standard LTC4065L/LTC4065LX is intended for back-up or high ambient temperature applications. Under these conditions, a reduced float voltage will trade-off initial cell capacity for the benefit of increased capacity retention over the life of the battery. A reduced float voltage also minimizes swelling in prismatic and polymer cells.

When the input supply (wall adapter or USB supply) is removed, the LTC4065L automatically enters a low current state, dropping battery drain current to less than 1µA. With power applied, LTC4065L can be put into shutdown mode, reducing the supply current to less than 20µA.

The full-featured LTC4065L also includes automatic recharge, low-battery charge conditioning (trickle charging) and soft-start (to limit inrush current).


  • Charger for Li-Ion Coin Cell Batteries
  • Portable MP3 Players, Wireless Headsets
  • Bluetooth Applications
  • Multifunction Wristwatches

Features and Benefits

  • Charge Current Programmable up to 250mA with 5% Accuracy
  • Complete Linear Charger in 2mm × 2mm DFN Package
  • C/10 Charge Current Detection Output
  • Timer Termination
  • No External MOSFET, Sense Resistor or Blocking Diode Required
  • Preset Float Voltage with 0.6% Accuracy:
  • Constant-Current/Constant-Voltage Operation with Thermal Feedback to Maximize Charging Rate Without Risk of Overheating
  • Charge Current Monitor Output for Gas Gauging
  • Automatic Recharge
  • Charges Single Cell Li-Ion Batteries Directly from USB Port
  • 20µA Supply Current in Shutdown Mode
  • Available Without Trickle Charge (LTC4065LX/ LTC4065LX-4.1)
  • Tiny 6-Lead (2mm × 2mm) DFN Package