LTC4075X_15 Datasheet, PDF (1/16 Pages) Linear Technology – Dual Input USB/AC Adapter Standalone Li-Ion Battery Chargers

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
■ _{No External MOSFET, Sense Resistor or Blocking}
Diode Needed
■ _{Thermal Regulation Maximizes Charging Rate}
Without Risk of Overheating*
■ _{Preset Charge Voltage with ±0.6% Accuracy}
■ _{Programmable Charge Current Termination}
■ _{18µA USB Suspend Current in Shutdown}
■ _{Independent “Power Present” Status Outputs}
■ _{Charge Status Output}
■ _{Automatic Recharge}
■ _{Available Without Trickle Charge (LTC4075X)}
■ _{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}
LTC4075/LTC4075X
Dual Input USB/AC
Adapter Standalone Li-Ion
Battery Chargers
DESCRIPTIO
The LTC^®4075/LTC4075X are standalone linear chargers
that are capable of charging a single-cell Li-Ion battery
from both wall adapter and USB inputs. The chargers 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 LTC4075
terminates the charge cycle when the charge current drops
below the programmed termination threshold after the
final float voltage is reached. With power applied to both
inputs, the LTC4075/LTC4075X 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.
Other features include automatic recharge, undervoltage
lockout, charge status outputs, and “power present”
status outputs to indicate the presence of wall adapter
or USB power.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Protected by U.S. patents, including 6522118, 6700364
TYPICAL APPLICATIO
Dual Input Battery Charger for Single-Cell Li-Ion
WALL
ADAPTER
USB
PORT
1µF
LTC4075
DCIN
BAT
USBIN
1µF
IUSB
2k
IDC
ITERM
1% _1.24k
GND
1%
800mA (WALL)
500mA (USB)
+ ^4.2V
SINGLE CELL
Li-Ion BATTERY
2k
1%
4075 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
–2.5
0
CONSTANT VOLTAGE
USBIN = 5V
T_A = 25°C
R_IDC = 1.25k
R_IUSB = 2k
0.5 1.0 1.5 2.0 2.5 3.0
TIME (HR)
4075 TA01b
4075Xfa
1