LTC4069

The LTC4069 is a complete constant-current/constant-voltage linear charger for single-cell lithium-ion batteries. The 2mm × 2mm DFN package and low external component count make the LTC4069 especially well-suited for portable applications. Furthermore, LTC4069 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 LTC4069 automatically enters a low current state, dropping battery drain current to less than 1μA. With power applied, LTC4069 can be put into shutdown mode, reducing the supply current to less than 20μA.

The LTC4069 also includes automatic recharge, low-battery charge conditioning (trickle charging), soft-start (to limit inrush current) and an NTC thermistor input used to monitor battery temperature.

The LTC4069 is available in a tiny 6-lead, low profile (0.75mm) 2mm × 2mm DFN package.

Applications

• Wireless PDAs
• Cellular Phones
• Portable Electronics