LTC4069-4.4
Standalone 750mA Li-Ion
Battery Charger in 2 × 2 DFN
with NTC Thermistor Input
DESCRIPTION
FEATURES
The LTC®4069-4.4 is a complete constant-current/
constant-voltagelinearchargerforhighcapacitysingle-cell
lithium-ion batteries with a 4.4V float voltage. The 2mm
× 2mm DFN package and low external component count
make the LTC4069-4.4 especially well-suited for portable
applications. Furthermore, LTC4069-4.4 is specifically
designed 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
Diode Required
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.
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NTC Thermistor Input for Temperature Qualified
Charging
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Preset 4.4V Float Voltage with 0.6% Accuracy
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Constant-Current/Constant-Voltage Operation with
Noexternalsenseresistororblockingdiodeisrequireddueto
theinternalMOSFETarchitecture.Thermalfeedbackregulates
chargecurrenttolimitthedietemperatureduringhighpower
operation or high ambient temperature conditions.
Thermal Feedback to Maximize Charge Rate
Without Risk of Overheating
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Charge Current Monitor Output for Gas Gauging
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Automatic Recharge
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Charges Single-Cell Li-Ion Batteries Directly from
When the input supply (wall adapter or USB supply) is
removed,theLTC4069-4.4automaticallyentersalowcurrent
state, dropping battery drain current to less than 1μA. With
powerapplied,LTC4069-4.4canbeputintoshutdownmode,
reducing the supply current to less than 20μA.
USB Port
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20μA Supply Current in Shutdown Mode
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Soft-Start Limits Inrush Current
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Tiny 6-Lead (2mm × 2mm) DFN Package
APPLICATIONS
The LTC4069-4.4 also includes automatic recharge, 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
Cellular Phones
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Portable Electronics
The LTC4069-4.4 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 (1100mAh Battery)
TYPICAL APPLICATION
550
500
450
400
350
300
250
200
150
100
50
4.5
4.4
4.3
4.2
4.1
4.0
3.9
3.8
3.7
3.6
3.5
3.4
CONSTANT-CURRENT
Standalone Li-Ion Battery Charger
500mA
CHRG
V
TRANSITION
IN
V
BAT
CC
4.5V TO 5.5V
CONSTANT-
VOLTAGE
R1
510Ω
LTC4069-4.4
R
NOM
100k
CHRG PROG
4.4V
+
Li-Ion
NTC
GND
BATTERY*
R
PROG
R
NTC
100k
1μF
2k
CHARGE
TERMINATION
4069 TA01
V
= 5V
PROG
CC
R
= 2K
*E.G. SANYO BATTERIES: UF553436T OR UF553450T
0
0
1
1.5
2
2.5
3
3.5
4
4.5
5
0.5
TIME (HOURS)
4069 TA01b
406944fa
1