LTC4065L Datasheet, PDF (1/16 Pages) Linear Technology – Standalone 250mA Li-Ion Battery Charger in 2 x 2 DFN

LTC4065L/LTC4065LX
Standalone 250mA Li-Ion
Battery Charger in 2 × 2 DFN
FEATURES
■ _{Charge Current Programmable up to 250mA with}
5% Accuracy
■ _{Complete Linear Charger in 2mm × 2mm DFN}
Package
■ _{C/10 Charge Current Detection Output}
■ _{Timer Termination}
■ _{No External MOSFET, Sense Resistor or Blocking}
Diode Required
■ _{Preset 4.2V Float Voltage with 0.6% Accuracy}
■ _{Constant-Current/Constant-Voltage Operation with}
Thermal Feedback to Maximize Charging Rate
Without Risk of Overheating
■ _{Charge Current Monitor Output for Gas Gauging}
■ _{Automatic Recharge}
■ _{Charges Single Cell Li-Ion Batteries Directly from}
USB Port
■ _{20µA Supply Current in Shutdown Mode}
■ _{Soft-Start Limits Inrush Current}
■ _{Available Without Trickle Charge (LTC4065LX)}
■ _{Tiny 6-Lead (2mmU× 2mm) DFN Package}
APPLICATIO S
■ _{Charger for Li-Ion Coin Cell Batteries}
■ _{Portable MP3 Players, Wireless Headsets}
■ _{Bluetooth Applications}
■ _{Multifunction Wristwatches}
, 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.
DESCRIPTIO
The LTC^®4065L is a complete constant-current/constant-
voltage linear charger for single-cell lithium-ion batteries.
Its small size and ability to accurately regulate low charge
currents make the LTC4065L especially well-suited for
portable applications using low capacity rechargeable
lithium-ion cells. Furthermore, LTC4065L is specifically
designed to work within USB power specifications.
The CHRG pin indicates when charge current has dropped
to ten percent of its programmed value (C/10). An internal
timer terminates charging according to battery manufac-
turer specifications.
No external sense resistor or blocking diode is required
due to the internal MOSFET architecture. Thermal feed-
back regulates charge current to limit the die temperature
during high power operation or high ambient temperature
conditions.
When the input supply (wall adapter or USB supply) is
removed, the LTC4065L automatically enters a low cur-
rent state, dropping battery drain current to less than 1µA.
With power applied, LTC4065L can be put into shutdown
mode, reducing the supply current to less than 20µA.
The full-featured LTC4065L also includes automatic re-
charge, low-battery charge conditioning (trickle charging)
and soft-start (to limit inrush current).
The LTC4065L is available in a tiny 6-lead, low profile
(0.75mm) 2mm × 2mm DFN package.
TYPICAL APPLICATIO
Standalone Li-Ion Battery Charger
V_IN
4.3V TO 5.5V
C1
1µF
R1
510Ω
V_CC BAT
LTC4065L
CHRG PROG
EN GND
100mA
+ ^4.2V
Li-Ion
R3
BATTERY
2k
4065L TA01
Complete Charge Cycle (180mAh Battery)
110
100
4.3
90 CONSTANT
80 ^CURRENT
70
CONSTANT
VOLTAGE
4.1
60
CHRG
3.9
50
TRANSITION
40
3.7
30
CHARGE
20
TERMINATION
3.5
10 ^VCC ^{= 5V}
0
R_PROG = 2k
3.3
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
TIME (HOURS)
4065 TA02
4065lxfa
1