The LTC4065-4.4 is a complete constant-current/constant-voltage linear charger for high capacity single-cell lithium-ion batteries with a 4.4V float voltage. Its 2mm × 2mm DFN package and low external component count make the LTC4065-4.4 especially well-suited for portable applications. Furthermore, LTC4065-4.4 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.

No external sense resistor or blocking diode is required due to the internal MOSFET architecture. Thermal feedback regulates charge current to limit the die temperature during high power operation or high ambient temperature conditions.

When the input supply (wall adapter or USB supply) is removed, the LTC4065-4.4 automatically enters a low current state, dropping battery drain current to less than 1µA. With power applied, LTC4065-4.4 can be put into shutdown mode, reducing the supply current to less than 20µA.

The full-featured LTC4065-4.4 also includes automatic recharge, low-battery charge conditioning (trickle charging) and soft-start (to limit inrush current).

The LTC4065-4.4 is available in a tiny 6-lead, low profile (0.75mm) 2mm × 2mm DFN package.

Applications

• Wireless PDAs
• Cellular Phones
• Portable Electronics