LTC4069
Standalone 750mA Li-Ion
Battery Charger in 2 × 2 DFN
with NTC Thermistor Input
DESCRIPTION
FEATURES
The LTC®4069 is a complete constant-current/constant-
voltage linear charger for single-cell lithium-ion batteries.
The2mm×2mmDFNpackageandlowexternalcomponent
countmaketheLTC4069especiallywell-suitedforportable
applications.Furthermore,LTC4069isspecificallydesigned
to work within USB power specifications.
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Complete Linear Charger in 2mm × 2mm DFN
Package
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C/10 Charge Current Detection Output
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Timer Charge Termination
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Charge Current Programmable up to 750mA with
5% Accuracy
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No External MOSFET, Sense Resistor or Blocking
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
manufacturer specifications.
Diode Required
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NTC Thermistor Input for Temperature Qualified
Charging
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Preset 4.2V Float Voltage with 0.6% Accuracy
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No external sense resistor or blocking diode is required
duetotheinternalMOSFETarchitecture.Thermalfeedback
regulates charge current to limit the die temperature
during high power operation or high ambient temperature
conditions.
Constant-Current/Constant-Voltage Operation with
Thermal Feedback to Maximize Charge Rate
Without Risk of Overheating
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Charge Current Monitor Output for Gas Gauging
Automatic Recharge
Charges Single Cell Li-Ion Batteries Directly from
USB Port
20μA Supply Current in Shutdown Mode
Soft-Start Limits Inrush Current
Tiny 6-Lead (2mm × 2mm) DFN Package
When the input supply (wall adapter or USB supply) is
removed, the LTC4069 automatically enters a low current
state,droppingbatterydraincurrenttolessthan1μA.With
power applied, LTC4069 can be put into shutdown mode,
reducing the supply current to less than 20μA.
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APPLICATIONS
TheLTC4069alsoincludesautomaticrecharge,low-battery
charge conditioning (trickle charging), soft-start (to limit
inrush current) and an NTC thermistor input used to
monitor battery temperature.
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Wireless PDAs
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Cellular Phones
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Portable Electronics
The LTC4069 is available in a tiny 6-lead, low profile
(0.75mm) 2mm × 2mm DFN package.
, 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.
Complete Charge Cycle (1000mAh Battery)
TYPICAL APPLICATION
Standalone Li-Ion Battery Charger
500mA
600
4.50
CONSTANT
CURRENT
CONSTANT
VOLTAGE
500
4.25
400
300
4.00
3.75
V
IN
V
BAT
LTC4069
CHRG PROG
NTC GND
CHRG
TRANSITION
CC
4.3V TO 5.5V
R1
510Ω
R
NOM
100k
4.2V
+
Li-Ion
200
100
0
3.50
3.25
3.00
BATTERY
CHARGE
TERMINATION
R
PROG
R
NTC
100k
1μF
2k
4069 TA01
V
= 5V
PROG
CC
R
= 2k
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
TIME (HOURS)
4069 TA01b
4069fb
1