LTC4069 Datasheet, PDF (1/16 Pages) Linear Technology – Standalone 750mA Li-Ion Battery Charger in 2 × 2 DFN with NTC Thermistor Input

LTC4069
FEATURES
Standalone 750mA Li-Ion
Battery Charger in 2 × 2 DFN
with NTC Thermistor Input
DESCRIPTION
n _{Complete Linear Charger in 2mm × 2mm DFN}
Package
n _{C/10 Charge Current Detection Output}
n _{Timer Charge Termination}
n _{Charge Current Programmable up to 750mA with}
5% Accuracy
n _{No External MOSFET, Sense Resistor or Blocking}
Diode Required
n _{NTC Thermistor Input for Temperature Qualified}
Charging
n _{Preset 4.2V Float Voltage with 0.6% Accuracy}
n _{Constant-Current/Constant-Voltage Operation with}
Thermal Feedback to Maximize Charge Rate
Without Risk of Overheating
n _{Charge Current Monitor Output for Gas Gauging}
n _{Automatic Recharge}
n _{Charges Single Cell Li-Ion Batteries Directly from}
USB Port
n _{20μA Supply Current in Shutdown Mode}
n _{Soft-Start Limits Inrush Current}
n _{Tiny 6-Lead (2mm × 2mm) DFN Package}
APPLICATIONS
n _{Wireless PDAs}
n _{Cellular Phones}
n _{Portable Electronics}
, 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, 6700364.
The LTC^®4069 is a complete constant-current/constant-
voltage linear charger for single-cell lithium-ion batteries.
The 2mm × 2mm DFN package and low external component
count make the LTC4069 especially well-suited for portable
applications. Furthermore, LTC4069 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
manufacturer specifications.
No external sense resistor or blocking diode is required
due to the internal MOSFET architecture. Thermal feedback
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 LTC4069 automatically enters a low current
state, dropping battery drain current to less than 1μA. With
power applied, LTC4069 can be put into shutdown mode,
reducing the supply current to less than 20μA.
The LTC4069 also includes automatic recharge, low-battery
charge conditioning (trickle charging), soft-start (to limit
inrush current) and an NTC thermistor input used to
monitor battery temperature.
The LTC4069 is available in a tiny 6-lead, low profile
(0.75mm) 2mm × 2mm DFN package.
TYPICAL APPLICATION
Standalone Li-Ion Battery Charger
V_IN
4.3V TO 5.5V
R_NOM
100k
R1
510Ω
R_NTC
1μF
100k
V_CC BAT
LTC4069
CHRG PROG
NTC GND
500mA
+
R_PROG
2k
4.2V
Li-Ion
BATTERY
4069 TA01
Complete Charge Cycle (1000mAh Battery)
600
CONSTANT
500 ^CURRENT
4.50
CONSTANT
VOLTAGE
4.25
400
CHRG
4.00
TRANSITION
300
3.75
200
CHARGE
TERMINATION
100
V_CC = 5V
0 ^{RPROG = 2k}
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
TIME (HOURS)
3.50
3.25
3.00
5
4069 TA01b
4069fb
1