LTC4056-4.2

1

405642f

The LTC

constant-voltage Li-Ion battery charger controller with a

programmable termination timer. When combined with a

few external components, the LTC4056 forms a very small

standalone charger for single cell lithium-ion batteries.

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 40

µA.

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.

The LTC4056 is available in a low profile (1mm) 8-lead

SOT-23 (ThinSOT

s

Cellular Telephones

s

Handheld Computers

s

Digital Cameras

s

Charging Docks and Cradles

s

Low Cost and Small Size Chargers

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

s

Standalone Li-Ion Charger with Termination

s

Programmable Termination Timer

s

No Sense Resistor or Blocking Diode Required

s

Suitable for USB-Powered Charging

s

Undervoltage Charge Current Limiting

s

Preset Charge Voltage with

±0.6% Accuracy

s

Programmable Charge Current: 200mA to 700mA

s

Automatic Recharge with Shortened Charge Cycle

s

Self-Protection for Overcurrent/Overtemperature

s

40

µA Supply Current in Shutdown Mode

s

Negligible Battery Drain Current in Shutdown

s

Low Battery Charge Conditioning (Trickle Charging)

s

CHRG Status Output including AC Present

s

s

Low Profile (1mm) SOT-23 Package

Linear Li-Ion Charger

with Termination in ThinSOT

CHRG

4.5V TO 6.5V

CHARGE

STATUS

DRIVE

TIMER/SHDN

BAT

PROG

GND

4056-4.2 TA01

1-CELL

4.2V Li-Ion

1

µF

1

µF

700mA

ZXT1M322

1.3k

LTC4056

+

ThinSOT is a trademark of Linear Technology Corporation.

4.40

4.70

4056 TA02

4.50

4.60

800

700

600

500

400

300

200

100

0

4.45

4.55

4.65

4.75

CONSTANT

CURRENT

UNDERVOLTAGE CHARGE

CURRENT LIMITING

UNDERVOLTAGE

LOCKOUT

AT 4.35V

INPUT Z = 100m

Ω

Current Limiting

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO