LTC4097

1

4097f

LTC4097

DCIN

USBIN

IUSB

IDC

BAT

VNTC

HPWR

NTC

ITERM

1.24k

1%

2k

1%

2k

1%

WALL

ADAPTER

USB

PORT

1

µF

1

µF

+

4.2V

SINGLE CELL

Li-Ion BATTERY

800mA (WALL)

100mA/500mA (USB)

4097 TA01

GND

T

TIME (HR)

0

4.2

200

0

400

800

600

1000

1.5

2.5

4097 TA01b

3.6

3.4

5.0

4.0

3.8

2.5

0

0.5

1.0

2.0

3.0

CONSTANT VOLTAGE

USBIN = 5V

HPWR = 5V

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

USB/Wall Adapter

Standalone Li-Ion/Polymer

Battery Charger

is capable of charging a single-cell Li-Ion or Li-Polymer

battery from both wall adapter and USB inputs. The charger

can detect power at the inputs and automatically select

the appropriate power source for charging.

No external sense resistor or blocking diode is required

for charging due to the internal MOSFET architecture.

Internal thermal feedback regulates the battery charge

current to maintain a constant die temperature during high

power operation or high ambient temperature conditions.

The float voltage is fixed at 4.2V and the charge current

is programmed with an external resistor. The LTC4097

terminates the charge cycle when the charge current drops

below the user programmed termination threshold after

the final float voltage is reached. The LTC4097 can be put

into shutdown mode reducing the DCIN supply current to

20µA, the USBIN supply current to 10µA, and the battery

drain current to less than 2µA even with power applied

to both inputs.

Other features include trickle charge, automatic recharge,

undervoltage lockout, charge status output, an NTC therm-

istor input used to monitor battery temperature and VNTC

power present output with 120mA drive capability.

Dual Input Battery Charger for Single-Cell Li-Ion Battery

, 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.

■

Charges Single-Cell Li-Ion/Polymer Battery from

Wall Adapter and USB Inputs

■

Automatic Input Detection (Wall Adapter Input has

Charging Priority)

■

Charge Current Programmable up to 1.2A from

Wall Adapter Input

■

Programmable Charge Current Termination

■

NTC Thermistor Input for Temperature Qualified

Charging

■

Independent DC, USB Charge Current Programming

■

Preset Float Voltage with ±0.6% Accuracy

■

Thermal Regulation Maximizes Charge Rate Without

Risk of Overheating*

■

Charge Status Output

■

Automatic Recharge

■

20µA Charger Quiescent Current in Shutdown

■

Available in a Thermally Enhanced, Low Profile

(0.75mm) 12-Lead (3mm × 2mm) DFN Package

■

Cellular Telephones

■

MP3 Players

■

Portable Handheld Devices

Complete Charge Cycle (1100mAh Battery)