A4054A

AiT Semiconductor Inc. www.ait-ic.com A4054A 800mA STANDALONE LINEAR Li-ion BATTERY CHARGER THERMAL REGULATION DESCRIPTION The A4054A is a complete constant current / constant voltage linear charger for single cell Lithium-Ion batteries. No external sense resistor is needed, and no blocking diode is required due to the internal MOSFET architecture. Thermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient temperature. The charge voltage is fixed at 4.2V, and the charge current can be programmed externally with a single resistor. The A4054A automatically terminates the charge cycle when the charge current drops to 1/10 the programmed value after the final float voltage is reached. When the input supply (wall adapter or USB supply) is removed, the A4054A automatically enters a low current state, dropping the battery drain current to less than 2μA. The A4054A can be put into shutdown mode, reducing the supply current to 25μA. Other features include charge current monitor, under-voltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage. A4054A will check the battery voltage first, it will not start charging unless the battery voltage is below the auto-rechrage threshold. The A4054A is available in SOT-25 packages. FEATURES  Programmable Charge Current Up to 800mA  No MOSFET, Sense Resistor or Blocking Diode Required  Preset 4.2V Charge Voltage with ±1%...