LTC2941
Battery Gas Gauge with I2C Interface
FEATURES
nn Indicates Accumulated Battery Charge
and Discharge
nn High Accuracy Analog Integration
nn High Side Sense
nn 1% Charge Accuracy
nn ±50mV Sense Voltage Range
nn SMBus/I2C Interface
nn Configurable Alert Output/Charge Complete Input
nn 2.7V to 5.5V Operating Range
nn Quiescent Current Less Than 100µA
nn Small 6-Pin 2mm × 3mm DFN and 8-Lead
MSOP Packages
APPLICATIONS
nn Low Power Handheld Products
nn Cellular Phones
nn MP3 Player
nn Cameras
nn GPS
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
thresholds 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 inter-
nal status register.
The LTC2941 requires only a single low value external
sense resistor to set the current range.
All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION
CHARGER
I2C/SMBus
TO HOST
SENSE+
LTC2941
AL/CC
SDA SENSE–
SCL
GND
RSENSE
100mΩ
+ 1-CELL
Li-Ion
2941 TA01a
LOAD
0.1µF
Total Charge Error vs
Differential Sense Voltage
2.0
VSENSE+ = 3.6V
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
0.1
1 10
VSENSE (mV)
100
2941 TA01b
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For more information www.analog.com
Rev. C
1
