1
LTC4065L/LTC4065LX
4065lxfa
■ Charger for Li-Ion Coin Cell Batteries
■
Portable MP3 Players, Wireless Headsets
■
Bluetooth Applications
Standalone 250mA Li-Ion
Battery Charger in 2
× 2 DFN
■
Charge Current Programmable up to 250mA with
5% Accuracy
■
Complete Linear Charger in 2mm
××××× 2mm DFN
Package
■
C/10 Charge Current Detection Output
■
Timer Termination
■
No External MOSFET, Sense Resistor or Blocking
Diode Required
■
Preset 4.2V 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
■ Available Without Trickle Charge (LTC4065LX)
■ Tiny 6-Lead (2mm
× 2mm) DFN Package
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
The LTC
4065L is a complete constant-current/constant-
voltage linear charger for single-cell lithium-ion batteries.
Its small size and ability to accurately regulate low charge
currents make the LTC4065L especially well-suited for
portable applications using low capacity rechargeable
lithium-ion cells. Furthermore, LTC4065L 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 feed-
back 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 LTC4065L automatically enters a low cur-
rent state, dropping battery drain current to less than 1
A.
With power applied, LTC4065L can be put into shutdown
mode, reducing the supply current to less than 20
A.
The full-featured LTC4065L also includes automatic re-
charge, low-battery charge conditioning (trickle charging)
and soft-start (to limit inrush current).
The LTC4065L is available in a tiny 6-lead, low profile
(0.75mm) 2mm
× 2mm DFN package.
Standalone Li-Ion Battery Charger
+
VCC
R1
510
100mA
R3
2k
4065L TA01
4.2V
Li-Ion
BATTERY
VIN
4.3V TO 5.5V
C1
1
F
LTC4065L
CHRG
EN
BAT
PROG
GND
■
Multifunction Wristwatches
Complete Charge Cycle (180mAh Battery)
TIME (HOURS)
0
CHARGE
CURRENT
(mA)
BATTERY
VOLTAGE
(V)
30
90
100
110
1
2
2.5
4065 TA02
10
70
50
20
80
0
60
40
4.3
3.5
4.1
3.3
3.9
3.7
0.5
1.5
3
3.5
4
4.5
CONSTANT
CURRENT
CONSTANT
VOLTAGE
CHRG
TRANSITION
CHARGE
TERMINATION
VCC = 5V
RPROG = 2k
, LTC and LT 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.