LTC4056-4.2
Linear Li-Ion Charger
with Termination in ThinSOT
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FEATURES
DESCRIPTIO
■
Standalone Li-Ion Charger with Termination
The LTC®4056 is a low cost, single-cell, constant-current/
constant-voltage Li-Ion battery charger controller with a
programmable termination timer. When combined with a
fewexternalcomponents, theLTC4056formsaverysmall
standalone charger for single cell lithium-ion batteries.
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Programmable Termination Timer
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No Sense Resistor or Blocking Diode Required
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Suitable for USB-Powered Charging
Undervoltage Charge Current Limiting
■
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Preset Charge Voltage with ±0.6% Accuracy
Charge current and charge time are set externally with a
single resistor and capacitor, respectively. The LTC4056
charges to a final float voltage accurate to ±0.6%. Manual
shutdown is accomplished by grounding the TIMER/
SHDN pin, while removing input power automatically puts
the LTC4056 into a sleep mode. Both the shutdown and
sleep modes drain near zero current from the battery; the
shutdown mode reduces supply current to 40µA.
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Programmable Charge Current: 200mA to 700mA
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Automatic Recharge with Shortened Charge Cycle
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Self-Protection for Overcurrent/Overtemperature
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40µA Supply Current in Shutdown Mode
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Negligible Battery Drain Current in Shutdown
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Low Battery Charge Conditioning (Trickle Charging)
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CHRG Status Output including AC Present
PCB Total Solution Area only 75mm2 (700mA)
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The output driver is both current limited and thermally
protected to prevent operating outside of safe limits. No
external blocking diode or sense resistor is required. The
LTC4056 also includes low battery charge conditioning
(trickle charging), undervoltage charge current limiting,
automatic recharge and a charge status output.
Low Profile (1mm) SOT-23 Package
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APPLICATIO S
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Cellular Telephones
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Handheld Computers
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Digital Cameras
Charging Docks and Cradles
Low Cost and Small Size Chargers
The LTC4056 is available in a low profile (1mm) 8-lead
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SOT-23 (ThinSOTTM) package.
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, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
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TYPICAL APPLICATIO
VIN Undervoltage Charge
Current Limiting
800
V
= 4V
BAT
CONSTANT
CURRENT
R
= 1.3k
PROG
700
600
500
400
300
200
100
0
I
= 700mA
CHG
INPUT Z = 100mΩ
LTC4056
V
IN
700mA
4.5V TO 6.5V
V
CC
I
SENSE
UNDERVOLTAGE CHARGE
CURRENT LIMITING
CHARGE
STATUS
CHRG
DRIVE
ZXT1M322
TIMER/SHDN BAT
1µF
+
1-CELL
4.2V Li-Ion
PROG
GND
1µF
1.3k
UNDERVOLTAGE
LOCKOUT
AT 4.35V
4056-4.2 TA01
4.45 4.50 4.55 4.60 4.65
4.75
4.70
4.40
V
IN
(V)
4056 TA02
405642f
1