Li-Ion Battery Charger with
Thermal Regulation in ThinSOT
s Programmable Charge Current Up to 800mA
s No MOSFET, Sense Resistor or Blocking
s Complete Linear Charger in ThinSOTTM Package for
Single Cell Lithium-Ion Batteries
s Constant-Current/Constant-Voltage Operation with
Thermal Regulation* to Maximize Charge Rate
Without Risk of Overheating
s Charges Single Cell Li-Ion Batteries Directly
from USB Port
s Preset 4.2V Charge Voltage with ±1% Accuracy
s Charge Current Monitor Output for Gas
s Automatic Recharge
s Charge Status Output Pin
s C/10 Charge Termination
s 25µA Supply Current in Shutdown
s 2.9V Trickle Charge Threshold (LTC4054)
s Available Without Trickle Charge (LTC4054X)
s Soft-Start Limits Inrush Current
s Available in 5-Lead SOT-23 Package
s Cellular Telephones, PDAs, MP3 Players
s Charging Docks and Cradles
s Bluetooth Applications
The LTC®4054 is a complete constant-current/constant-
voltage linear charger for single cell lithium-ion batteries.
Its ThinSOT package and low external component count
make the LTC4054 ideally suited for portable applications.
Furthermore, the LTC4054 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 LTC4054 automatically terminates
the charge cycle when the charge current drops to 1/10th
the programmed value after the final float voltage is
When the input supply (wall adapter or USB supply) is
removed, the LTC4054 automatically enters a low current
state, dropping the battery drain current to less than 2µA.
The LTC4054 can be put into shutdown mode, reducing
the supply current to 25µA.
Other features include charge current monitor, undervoltage
lockout, automatic recharge and a status pin to indicate
charge termination and the presence of an input voltage.
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
*U.S.Patent No. 6,522,118
600mA Single Cell Li-Ion Charger
4.5V TO 6.5V
VCC BAT 3
Complete Charge Cycle (750mAh Battery)
VCC = 5V
θJA = 130°C/W
RPROG = 1.65k
0 TA = 25°C
0 0.25 0.5 0.75 1.0 1.25 1.5 1.75 2.0