LTC2941 Datasheet, PDF (1/16 Pages) Linear Technology – Battery Gas Gauge with I2C Interface

FEATURES
n _{Indicates Accumulated Battery Charge and}
Discharge
n _{High Accuracy Analog Integration}
n _{High Side Sense}
n _{1% Charge Accuracy}
n _{±50mV Sense Voltage Range}
n _SMBus/I²_{C Interface}
n _{Configurable Alert Output/Charge Complete Input}
n _{2.7V to 5.5V Operating Range}
n _{Quiescent Current Less than 100μA}
n _{Small 6-Pin 2mm × 3mm DFN package}
APPLICATIONS
n _{Low Power Handheld Products}
n _{Cellular Phones}
n _{MP3 Player}
n _Cameras
n _GPS
LTC2941
Battery Gas Gauge
with I²C Interface
DESCRIPTION
The LTC^®2941 measures battery charge state in battery-
supplied handheld PC and portable product applications.
Its operating range is perfectly suited for single cell Li-Ion
batteries. A precision coulomb counter integrates current
through a sense resistor between the battery’s positive
terminal and the load or charger. The measured charge
is stored in internal registers. An SMBus/I²C interface
accesses and configures the device.
The LTC2941 features programmable high and low thresh-
olds for accumulated charge. If a threshold is exceeded,
the device communicates an alert using either the SMBus
alert protocol or by setting a flag in the internal status
register.
The LTC2941 requires only a single low value external
sense resistor to set the current range.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
CHARGER
I²C/SMBus
TO HOST
SENSE⁺
LTC2941
AL/CC
SDA SENSE^–
SCL
GND
R_SENSE
100mΩ
+ _1-CELL
Li-Ion
2941 TA01a
LOAD
0.1μF
Total Charge Error vs
Differential Sense Voltage
2.0
V_SENSE+ = 3.6V
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
0.1
1
10
V_SENSE (mV)
100
2941 TA01b
2941f
1