DESCRIPTION

The A4056 is a complete constant-current /constant -voltage linear charger for single cell lithium-ion batteries. Its Thin SOT package and low external component count make the A4056 ideally suited for portable applications. Furthermore, the A4056 is specifically designed to work within USB power specifications.

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 A4056 automatically terminates the charge cycle when the charge current drops to 1/10th the programmed value after the final float voltage is reached.

When the input supply (wall adapter or USB supply) is removed, the A4056 automatically enters a low current state, dropping the battery drain current to less than 2μA. The A4056 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.

The A4056 is available in SOT 26 package.

FEATURES

⚫ Programmable charge current up to 500mA

⚫ No MOSFET, sense resistor or blocking diode

required

⚫ Complete linear charger in Thin SOT package

for single cell lithium ion batteries

⚫ Constant current/constant voltage operation with

thermal regulation to maximize charge rate

without risk of over heating

⚫ Charges single cell li ion batteries directly from

USB port

⚫ Preset 4.2V charge voltage with 1 a ccuracy

⚫ Charge current monitor output for gas gauging

⚫ Charge status output pin

⚫ C/10 charge termination

⚫ 25μA supply current in shutdown

⚫ 2.9V trick le charge threshold (A4056)

⚫ Soft start limits inrush current

⚫ Available in SOT 26 p ackage

APPLICATION

⚫ Cellular Telephones, PDAs, MP3 Players

⚫ Bluetooth Applications