Standalone 750mA Li-Ion
Battery Charger in 2 × 2 DFN
with NTC Thermistor Input
n Complete Linear Charger in 2mm × 2mm DFN
n C/10 Charge Current Detection Output
n Timer Charge Termination
n Charge Current Programmable Up to 750mA with
n No External MOSFET, Sense Resistor or Blocking
n NTC Thermistor Input for Temperature Qualiﬁed
n Preset 4.4V Float Voltage with 0.6% Accuracy
n Constant-Current/Constant-Voltage Operation with
Thermal Feedback to Maximize Charge Rate
Without Risk of Overheating
n Charge Current Monitor Output for Gas Gauging
n Automatic Recharge
n Charges Single-Cell Li-Ion Batteries Directly from
n 20μA Supply Current in Shutdown Mode
n Soft-Start Limits Inrush Current
n Tiny 6-Lead (2mm × 2mm) DFN Package
n Wireless PDAs
n Cellular Phones
n Portable Electronics
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 6522118, 6700364.
The LTC®4069-4.4 is a complete constant-current/
constant-voltage linear charger for high capacity single-cell
lithium-ion batteries with a 4.4V ﬂoat voltage. The 2mm
× 2mm DFN package and low external component count
make the LTC4069-4.4 especially well-suited for portable
applications. Furthermore, LTC4069-4.4 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
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 LTC4069-4.4 automatically enters a low current
state, dropping battery drain current to less than 1μA. With
power applied, LTC4069-4.4 can be put into shutdown mode,
reducing the supply current to less than 20μA.
The LTC4069-4.4 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 LTC4069-4.4 is available in a tiny 6-lead, low proﬁle
(0.75mm) 2mm × 2mm DFN package.
Standalone Li-Ion Battery Charger
4.5V TO 5.5V
*E.G. SANYO BATTERIES: UF553436T OR UF553450T
Complete Charge Cycle (1100mAh Battery)
VCC = 5V
RPROG = 2K
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5