LTC1733

1

sn1733 1733fs

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO

s

Cellular Telephones

s

Handheld Computers

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Digital Still Cameras

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Charging Docks and Cradles

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Complete Linear Charger for 1-Cell Lithium-Ion

Batteries

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Thermal Regulation Maximizes Charging Rate

without Risk of Overheating*

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No External MOSFET, Sense Resistor or Blocking

Diode Required

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Up to 1.5A Charge Current

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Preset Charge Voltage with 1% Accuracy

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Programmable Charge Current with 7% Accuracy

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Programmable Charge Termination Timer

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Tiny Thermally Enhanced 10-Pin MSOP Package

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Charge Current Monitor Useful for Gas Gauging*

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C/10 Charge Current Detection Output

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Automatic Recharge

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Thermistor Input for Temperature Qualified Charging

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AC Present Logic Output

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4.1V/4.2V Pin Selectable Output Voltage

Monolithic Linear

Lithium-Ion Battery Charger with

Thermal Regulation

The LTC

constant-voltage linear charger for lithium-ion batteries

with an on-chip power MOSFET. Internal thermal feedback

regulates the charge current to limit die temperature

during high power operation or high ambient temperature

conditions. This feature allows the user to program a high

charge current without risk of damaging the LTC1733 or

the handheld product.

No external current sense resistor is needed and no

blocking diode is required due to the internal MOSFET

architecture. The charge current and charge time can be

set externally with a single resistor and capacitor, respec-

tively. When the input supply (wall adapter) is removed,

the LTC1733 automatically enters a low current sleep

mode, dropping the battery drain current to less than 5

µA.

The LTC1733 also includes NTC temperature sensing,

C/10 detection circuitry, AC present logic, 4.1V/4.2V pin

selectability and low battery charge conditioning (trickle

charging).

The LTC1733 is available in a 10-pin thermally enhanced

MSOP package.

, LTC and LT are registered trademarks of Linear Technology Corporation.

Charge Current vs Battery Voltage

Standalone Li-Ion Battery Charger

BATTERY VOLTAGE (V)

2

3.5

1733 TA01b

2.5

3

4

4.5

1200

1000

800

600

400

200

0

TRICKLE

CHARGE

CONSTANT

CURRENT

CONSTANT

VOLTAGE

CONSTANT

POWER

*Patent Pending

BAT

PROG

TIMER

GND

1.5k

1%

4.7

µF

0.1

µF

1733TA01

LTC1733

4.2V

1-CELL

Li-Ion

BATTERY*

*AN OUTPUT CAPACITOR MAY BE REQUIRED

DEPENDING ON BATTERY LEAD LENGTH

2

8

9

7

5

NTC

6

4

SEL