LTC4077_15 Datasheet, PDF (1/16 Pages) Linear Technology – Dual Input Standalone Li-Ion Battery Charger

FEATURES
■ _{Charges Single-Cell Li-Ion Batteries from Wall}
Adapter and USB Inputs
■ _{Automatic Input Power Detection and Selection}
■ _{Charge Current Programmable up to 950mA from}
Wall Adapter Input
■ _{C/10 Charge Current Termination}
■ _{Thermal Regulation Maximizes Charge Rate}
Without Risk of Overheating*
■ _{Preset Charge Voltage with ±0.6% Accuracy}
■ _{18µA USB Suspend Current in Shutdown}
■ _{Power Present Status Output}
■ _{Charge Status Output}
■ _{Automatic Recharge}
■ _{Available in a Thermally Enhanced, Low Profile}
(0.75mm) 10-Lead (3mm × 3mm) DFN Package
U
APPLICATIO S
■ _{Cellular Telephones}
■ _{Handheld Computers}
■ _{Portable MP3 Players}
■ _{Digital Cameras}
LTC4077
Dual Input Standalone
Li-Ion Battery Charger
DESCRIPTIO
The LTC^®4077 is a standalone linear charger that is capable
of charging a single-cell Li-Ion 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 LTC4077
terminates the charge cycle when the charge current drops
below the termination threshold after the final float voltage
is reached. The LTC4077 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 automatic recharge, undervoltage
lockout, charge status output, power present status output
to indicate the presence of wall adapter or USB power and
high power/low power adjustable mode for USB compat-
ible applications.
, 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
TYPICAL APPLICATIO
Dual Input Battery Charger for Single-Cell Li-Ion
WALL
ADAPTER
USB
PORT
1F
LTC4077
DCIN
BAT
USBIN HPWR
1F
IUSB
2k
IDC
IUSBL
1% _1.24k
GND
1%
800mA (WALL)
500mA (USB)
+ ^4.2V
SINGLE CELL
Li-Ion BATTERY
2k
1%
4077 TA01
Complete Charge Cycle (1100mAh Battery)
1000
800
600
400
200
0
4.2
4.0
3.8
3.6
3.4
5.0
2.5
0
CONSTANT VOLTAGE
USBIN = 5V
T_A = 25°C
R_IDC = 1.24k
R_IUSB = 2k
HPWR = 5V
0 0.5 1.0 1.5 2.0 2.5 3.0
TIME (HR)
4077fa
1