LTC4069-4.4

The LTC®4069-4.4 is a complete constant-current/ constant-voltage linear charger for high capacity single-cell lithium-ion batteries with a 4.4V fl oat voltage. The 2mm * 2mm DFN package and low external component count make the LTC4069-4.4 especially well-suited for portable applications. Furthermore, LTC4069-4.4 is specifi cally designed to work within USB power specifi cations.

The CHRG pin of LTC4069-4.4 indicates when charge current has dropped to ten percent of its programmed value (C/10). An internal timer terminates charging according to battery manufacturer specifi cations. 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 LTC4069-4.4 automatically enters a low current state, dropping battery drain current to less than 1A. With power applied, LTC4069-4.4 can be put into shutdown mode, reducing the supply current to less than 20A.

The LTC4069-4.4 also includes automatic recharge, lowbattery charge conditioning (trickle charging), soft-start (to limit inrush current) and an NTC thermistor input used to monitor battery temperature. The LTC4069-4.4 is available in a tiny 6-lead, low profi le (0.75mm) 2mm * 2mm DFN package.