LTC4054L-4.2
150mA Standalone Linear
Li-Ion Battery Charger in ThinSOT
DESCRIPTIO
The LTC
®
4054L is a complete, constant-current/constant-
voltage linear charger for single cell lithium-ion batteries.
Its small size and ability to regulate low charge currents
make the LTC4054L especially well-suited for portable
applications using low capacity rechargeable lithium-ion
coin cells. Furthermore, the LTC4054L is specifically de-
signed to work within USB power specifications.
No external sense resistor is needed, and no blocking di-
ode is required due to the internal MOSFET architecture.
Thermal feedback regulates the charge current to eliminate
thermal overdesign. The charge voltage is fixed at 4.2V, and
the charge current can be programmed externally with a
single resistor. The LTC4054L automatically terminates a
charge cycle when the charge current drops to 1/10th the
programmed value after the final float voltage is reached.
When the input supply (wall adapter or USB supply) is
removed, the LTC4054L automatically enters a low cur-
rent state, dropping the battery drain current to less than
2µA. The LTC4054L can be put into shutdown mode, re-
ducing 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
FEATURES
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Programmable Charge Current Range:
10mA to 150mA
No External MOSFET, Sense Resistor or Blocking
Diode Required
Complete Linear Charger in ThinSOT
TM
Package for
Single Cell/Coin Cell Lithium-Ion Batteries
Constant-Current/Constant-Voltage Operation with
Thermal Regulation* to Maximize Charge Rate
Without Risk of Overheating
Charges Single Cell Li-Ion Batteries Directly
from USB Port
Preset 4.2V Charge Voltage with
±1%
Accuracy
Charge Current Monitor Output for Gas Gauging*
Automatic Recharge
Charge Status Output Pin
C/10 Charge Termination
25µA Max Supply Current in Shutdown Mode
2.9V Trickle Charge Threshold
Soft-Start Limits Inrush Current
Available in a 6-Lead Low Profile (1mm)
SOT-23 Package
APPLICATIO S
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Charger for Li-Ion Coin Cell Batteries
Portable MP3 Players, Wireless Headsets
Bluetooth Applications
Multifunction Wristwatches
TYPICAL APPLICATIO
V
IN
4.5V TO 6.5V
1µF
Complete Charge Cycle (130mAh Battery)
100
4.4
CONSTANT
CURRENT
4.3
CONSTANT
VOLTAGE
4.2
BATTERY VOLTAGE (V)
90mA Li-Ion Single Coin Cell Charger
CHARGE CURRENT (mA)
90
80
70
60
50
40
30
20
10
0
4
BAT
LTC4054L-4.2
PROG
GND
2
V
CC
3
90mA
5
1.69k
4.2V
COIN CELL
Li-Ion
BATTERY
4054l42 TA01
3.4
0 0.25 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25
TIME (HOURS)
4054l42 TA01b
V
CC
= 5V
θ
JA
= 130°C/W
R
PROG
= 1.69k
T
A
= 25°C
U
U
U
4.1
4.0
3.9
3.8
3.7
3.6
3.5
4054l42f
1
LINER [ LINEAR TECHNOLOGY ]
