General Description
ME4057 is a complete constant-current/constant voltage
linear charger for single cell lithium-ion batteries. With a
thermally enhanced 8-PIN SOP package on the bottom
and low external component count make the ME4057
ideally suited for portable applications. Furthermore the
ME4057 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 PMOSFET
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 ME4057 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 ME4057 automatically enters a low current
state dropping the battery drain current to less than
2μA.The ME4057 can be put into shutdown mode reducing
the supply current to 55μA.
Other features include Battery temperature monitor,
under-voltage lockout, automatic recharge and two status
pins to indicate charge and charge termination.