LTC4061
Standalone Linear Li-Ion Battery
Charger with Thermistor Input
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FEATURES
DESCRIPTIO
The LTC®4061 is a full-featured, flexible, standalone linear
charger for single-cell Lithium-Ion batteries. It is capable
of operating within USB power specifications.
■
Charge Current Programmable up to 1A
■
Charges Single Cell Li-Ion Batteries Directly from
USB Port
■
Preset Charge Voltage with ±±0.35 Accuracy
Both programmable time and programmable current
based termination schemes are available. Furthermore,
the CHRG open-drain status pin can be programmed to
indicate the battery charge state according to the needs
of the application. Additional safety features designed to
maximize battery lifetime and reliability include NTC bat-
tery temperature sensing and the SmartStartTM charging
algorithm.
■
Thermistor Input for Temperature Qualified
Charging
Input Supply Present Logic Output
■
■
Thermal Regulation Maximizes Charge Rate
Without Risk of Overheating*
■
Programmable Charge Current Detection/
Termination
■
Programmable Charge Termination Timer
No external sense resistor or external blocking diode is
required for charging due to the internal MOSFET archi-
tecture. Internal thermal feedback regulates the charge
current to maintain a constant die temperature during
high power operation or high ambient temperature condi-
tions. The charge current is programmed with an external
resistor. With power applied, the LTC4061 can be put into
shutdown mode to reduce the supply current to 20µA and
the battery drain current to less than 2µA.
■
Smart Pulsing Error Feature
SmartStartTM Prolongs Battery Life
■
■
20µA Charger Quiescent Current in Shutdown
■
Available in a Low Profile (0.75mm) 10-Lead
(3mm × 3mm) DFN Package
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APPLICATIO S
■
Handheld Computers
■
Portable MP3 Players
Other features include smart recharge, USB C/5 cur-
rent programming input, undervoltage lockout and AC
Present logic.
■
Digital Cameras
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
SmartStart is a trademark of Linear Technology Corporation.
*Protected by U.S. Patents including 6522118.
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Complete Charge Cycle (11±±mAh Battery)
TYPICAL APPLICATIO
900
800
700
600
500
400
300
200
100
0
4.3
4.2
4.1
4.0
3.9
3.8
3.7
3.6
3.5
3.4
8±±mA Single Cell Li-Ion Battery Charger
(C/1± Termination)
800mA
V
IN
V
BAT
CC
4.3V TO 8V
LTC4061
EN
1µF
CHRG
ACPR
NTC
C/5
BATTERY
CURRENT
BATTERY
VOLTAGE
4.2V
SINGLE CELL
Li-Ion BATTERY
+
TIMER
PROG
I
DET
GND
V
A
= 5V
CC
619Ω
T
= 25°C
4061 TA01a
0
0.5
1.0
1.5
2.0
2.5
3.0
TIME (HOURS)
4061 TA01b
4061fa
1