LTC1733_15 Datasheet, PDF (1/16 Pages) Linear Technology – Monolithic Linear Lithium-Ion Battery Charger with Thermal Regulation

LTC1733
Monolithic Linear
Lithium-Ion Battery Charger with
Thermal Regulation
FEATURES
s _{Complete Linear Charger for 1-Cell Lithium-Ion}
Batteries
s _{Thermal Regulation Maximizes Charging Rate}
without Risk of Overheating*
s _{No External MOSFET, Sense Resistor or Blocking}
Diode Required
s _{Up to 1.5A Charge Current}
s _{Preset Charge Voltage with 1% Accuracy}
s _{Programmable Charge Current with 7% Accuracy}
s _{Programmable Charge Termination Timer}
s _{Tiny Thermally Enhanced 10-Pin MSOP Package}
s _{Charge Current Monitor Useful for Gas Gauging*}
s _{C/10 Charge Current Detection Output}
s _{Automatic Recharge}
s _{Thermistor Input for Temperature Qualified Charging}
s _{AC Present Logic Output}
s _{4.1V/4.2V Pin Selectable Output Voltage}
U
APPLICATIO S
s _{Cellular Telephones}
s _{Handheld Computers}
s _{Digital Still Cameras}
s _{Charging Docks and Cradles}
DESCRIPTIO
The LTC^®1733 is a standalone constant-current/
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 5µA.
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.
*Patent Pending
TYPICAL APPLICATIO
Standalone Li-Ion Battery Charger
V_IN = 5V
8
2
4.7µF
SEL V_CC
9
BAT
4
LTC1733
7
TIMER PROG
GND NTC
0.1µF 5
6
I_BAT = 1A
4.2V
1-CELL
Li-Ion
1.5k ^BATTERY*
1%
1733TA01
*AN OUTPUT CAPACITOR MAY BE REQUIRED
DEPENDING ON BATTERY LEAD LENGTH
Charge Current vs Battery Voltage
1200
1000
T_A = 0°C
CONSTANT
CURRENT
800
T_A = 40°C
T_A = 25°C
600
CONSTANT
POWER
400
CONSTANT
VOLTAGE
200 ^TRICKLE
CHARGE
V_IN = 5V
θ_JA = 40°C/W
0
2
2.5
3
3.5
4
BATTERY VOLTAGE (V)
4.5
1733 TA01b
sn1733 1733fs
1