
1
LTC4065-4.4
406544f
■ Wireless PDAs
■
Cellular Phones
■
Portable Electronics
Standalone 750mA Li-Ion
Battery Charger in 2
× 2 DFN
■
Complete Linear Charger in 2mm
××××× 2mm DFN
Package
■
C/10 Charge Current Detection Output
■
Timer Termination
■
Charge Current Programmable Up to 750mA with
5% Accuracy
■
No External MOSFET, Sense Resistor or Blocking
Diode Required
■
Preset 4.4V Float Voltage with 0.6% Accuracy
■
Constant-Current/Constant-Voltage Operation with
Thermal Feedback to Maximize Charging Rate
Without Risk of Overheating
■
Charge Current Monitor Output for Gas Gauging
■
Automatic Recharge
■
Charges Single-cell Li-Ion Batteries Directly from
USB Port
■
20
A Supply Current in Shutdown Mode
■ Soft-Start Limits Inrush Current
■ Tiny 6-Lead (2mm
× 2mm) DFN Package
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
+
VCC
R1
510
500mA
R3
2k
4065 TA01
4.4V
Li-Ion
BATTERY*
VIN
4.5V TO
5.5V
C1
1
F
*E.G. SANYO BATTERIES: UF553436T OR UF553450T
LTC4065-4.4
CHRG
EN
BAT
PROG
GND
The LTC
4065-4.4 is a complete constant-current/con-
stant-voltage linear charger for high capacity single-cell
lithium-ion batteries with a 4.4V float voltage. Its 2mm
×
2mm DFN package and low external component count
make the LTC4065-4.4 especially well-suited for portable
applications. Furthermore, LTC4065-4.4 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 manufac-
turer specifications.
No external sense resistor or blocking diode is required due
to the internal MOSFET architecture. Thermal feedback regu-
lates 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 LTC4065-4.4 automatically enters a low cur-
rent state, dropping battery drain current to less than
1
A. With power applied, LTC4065-4.4 can be put into shut-
down mode, reducing the supply current to less than 20
A.
The full-featured LTC4065-4.4 also includes automatic
recharge, low-battery charge conditioning (trickle charg-
ing) and soft-start (to limit inrush current).
The LTC4065-4.4 is available in a tiny 6-lead, low profile
(0.75mm) 2mm
× 2mm DFN package.
Standalone Li-Ion Battery Charger
, 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.
TIME (HOURS)
0
CHARGE
CURRENT
(mA)
150
450
500
550
1
2
3
4065 TA01b
50
350
250
100
400
0
300
200
BATTERY
VOLTAGE
(V)
3.7
4.3
4.4
4.5
3.5
4.1
3.9
3.6
4.2
3.4
4.0
3.8
0.5
1.5
4
5
2.5
3.5
4.5
CONSTANT-CURRENT
CONSTANT-
VOLTAGE
VCC = 5V
RPROG = 2K
CHARGE
TERMINATION
CHRG
TRANSITION
Complete Charge Cycle (1100mAh Battery)