LTC4065LX_15 Datasheet, PDF (1/18 Pages) Linear Technology – Standalone 250mA Li-Ion Battery Charger

LTC4065L/
LTC4065LX/LTC4065L-4.1
Standalone 250mA Li-Ion
Battery Charger in 2 × 2 DFN
FEATURES
DESCRIPTION
n _{Charge Current Programmable up to 250mA with}
5% Accuracy
n _{Complete Linear Charger in 2mm × 2mm DFN Package}
n _{C/10 Charge Current Detection Output}
n _{Timer Termination}
n _{No External MOSFET, Sense Resistor or Blocking}
Diode Required
n _{Preset Float Voltage with 0.6% Accuracy:}
4.2V for LTC4065L/LTC4065LX
4.1V for LTC4065L-4.1
n _{Constant-Current/Constant-Voltage Operation with}
Thermal Feedback to Maximize Charging 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}
USB Port
n _{20μA Supply Current in Shutdown Mode}
n _{Available Without Trickle Charge (LTC4065LX)}
n _{Tiny 6-Lead (2mm × 2mm) DFN Package}
APPLICATIONS
n _{Charger for Li-Ion Coin Cell Batteries}
n _{Portable MP3 Players, Wireless Headsets}
n _{Bluetooth Applications}
n _{Multifunction Wristwatches}
L, LT, LTC, LTM, Linear Technology and the Linear logo 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^®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.
The LTC4065L-4.1 features a constant-voltage float voltage
of 4.1V. This 4.1V version of the standard LTC4065L is in-
tended for back-up or high ambient temperature applications.
Under these conditions, a reduced float voltage will trade-
off initial cell capacity for the benefit of increased capacity
retention over the life of the battery. A reduced float voltage
also minimizes swelling in prismatic and polymer cells.
When the input supply (wall adapter or USB supply) is
removed, the LTC4065L automatically enters a low current
state, dropping battery drain current to less than 1μA. With
power applied, LTC4065L can be put into shutdown mode,
reducing the supply current to less than 20μA.
The full-featured LTC4065L also includes automatic re-
charge, low-battery charge conditioning (trickle charging)
and soft-start (to limit inrush current).
TYPICAL APPLICATION
Standalone Li-Ion Battery Charger
V_IN
4.3V TO 5.5V
C1
1μF
R1
510Ω
V_CC BAT
LTC4065L
CHRG PROG
EN GND
100mA
+ ^4.2V
Li-Ion
R3
BATTERY
2k
4065L TA01
Complete Charge Cycle (180mAh Battery)
LTC4065L and LTC4065LX
110
100
4.3
90 CONSTANT
80 ^CURRENT
70
CONSTANT
VOLTAGE
4.1
60
CHRG
3.9
50
TRANSITION
40
3.7
30
20
10
0
0
CHARGE
TERMINATION
3.5
V_CC = 5V
R_PROG = 2k
3.3
0.5 1 1.5 2 2.5 3 3.5 4 4.5
TIME (HOURS)
4065 TA02
4065lfb
1