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/I
2
C 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.
Indicates Accumulated Battery Charge
and Discharge
High Accuracy Analog Integration
High Side Sense
1% Charge Accuracy
±50mV Sense Voltage Range
SMBus/I
2
C Interface
Configurable Alert Output/Charge Complete Input
2.7V to 5.5V Operating Range
Quiescent Current Less Than 100µA
Small 6-Pin 2mm × 3mm DFN and 8-Lead
MSOP Packages
APPLICATIONS
n
n
n
n
n
Low Power Handheld Products
Cellular Phones
MP3 Player
Cameras
GPS
TYPICAL APPLICATION
Total Charge Error vs
Differential Sense Voltage
CHARGER
SENSE
+
LTC2941
AL/CC
SDA
SENSE
–
SCL
GND
LOAD
0.1µF
R
SENSE
100m
2.0
1.5
CHARGE ERROR (%)
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
0.1
1
V
SENSE
(mV)
2941 TA01b
V
SENSE+
= 3.6V
I
2
C/SMBus
TO HOST
+
1-CELL
Li-Ion
2941 TA01a
10
100
Document Feedback
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1
Rev. C
LTC2941
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Supply Voltage (SENSE
+
) ............................. –0.3V to 6V
SCL, SDA,
AL/CC
......................................... –0.3V to 6V
SENSE
–
.................................. –0.3V to (V
SENSE+
+ 0.3V)
Operating Ambient Temperature Range
LTC2941C ................................................ 0°C to 70°C
LTC2941I..............................................–40°C to 85°C
Storage Temperature Range .................... –65°C to 150°
PIN CONFIGURATION
TOP VIEW
SENSE
+
1
GND 2
SCL 3
7
6 SENSE
–
5
AL/CC
4 SDA
TOP VIEW
SENSE
+
GND
SCL
DNC
1
2
3
4
9
8
7
6
5
SENSE
–
AL/CC
SDA
DNC
DCB PACKAGE
6-LEAD (2mm
×
3mm) PLASTIC DFN
T
JMAX
= 150°C,
θ
JA
= 120°C/W
EXPOSED PAD (PIN 7), DO NOT CONNECT
MSE PACKAGE
8-LEAD PLASTIC MSOP
PIN 4, PIN 5 AND EXPOSED PAD (PIN 9), DO NOT CONNECT
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI)
LTC2941CDCB#TRMPBF
LTC2941IDCB#TRMPBF
TUBE
LTC2941CMS8E#PBF
TAPE AND REEL
LTC2941CDCB#TRPBF
LTC2941IDCB#TRPBF
TAPE AND REEL
LTC2941CMS8E#TRPBF
PART MARKING*
LFKQ
LFKQ
PART MARKING*
LTGVY
PACKAGE DESCRIPTION
6-Lead (2mm × 3mm) Plastic DFN
6-Lead (2mm × 3mm) Plastic DFN
PACKAGE DESCRIPTION
8-Lead Plastic MSOP
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
TEMPERATURE RANGE
0°C to 70°C
LTC2941IMS8E#PBF
LTC2941IMS8E#TRPBF
LTGVY
8-Lead Plastic MSOP
–40°C to 85°C
TRM = 500 pieces.
Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Tape and reel specifications.
Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix.
2
Rev. C
For more information
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LTC2941
ELECTRICAL CHARACTERISTICS
SYMBOL
V
SENSE+
I
SUPPLY
PARAMETER
Supply Voltage
Supply Current (Note 3)
Device On
Shutdown
Shutdown, V
SENSE+
≤ 4.2V
V
UVLO
Undervoltage Lockout Threshold
V
SENSE+
Falling, DCB Package
V
SENSE+
Falling, MSE Package
V
SENSE+
– V
SENSE–
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 2)
CONDITIONS
MIN
2.7
70
TYP
MAX
5.5
100
2.5
1
2.5
2.45
2.6
2.6
2.7
2.7
±50
400
Prescaler M = 128 (Default),
R
SENSE
= 50mΩ
10mV ≤ |V
SENSE
| ≤ 50mV DC
10mV ≤ |V
SENSE
| ≤ 50mV, DC V
SENSE+
≤ 4.2V
1mV ≤ |V
SENSE
| ≤ 50mV DC (Note 7)
l
l
l
l
l
UNITS
V
µA
µA
µA
V
V
mV
kΩ
mAh
Power Requirements
Coulomb Counter
V
SENSE
Sense Voltage Differential Input Range
Differential Input Resistance, Across
SENSE
+
and SENSE
–
(Note 7)
q
LSB
TCE
Charge LSB (Note 4)
Total Charge Error (Note 5)
l
0.085
±1
±1.5
±3.5
2.75
2.85
2.95
0.3 •
V
SENSE+
2.8
2.9
3
2.85
2.95
3.05
0.7 •
V
SENSE+
0.4
1
10
1
%
%
%
V
V
V
V
V
µA
pF
µs
V
BAT
Alert
V
BAT
Alert Threshold
V
SENSE+
Falling, B[7:6] = 01
V
SENSE+
Falling, B[7:6] = 10
V
SENSE+
Falling, B[7:6] = 11
Digital Inputs and Digital Outputs
V
ITH
V
OL
I
IN
C
IN
t
PCC
Logic Input Threshold,
AL/CC,
SCL, SDA
Low Level Output Voltage,
AL/CC,
SDA I = 3mA
Input Leakage,
AL/CC,
SCL, SDA
Input Capacitance,
AL/CC,
SCL, SDA
Minimum Charge Complete (CC)
Pulse Width
Maximum SCL Clock Frequency
Bus Free Time Between STOP/START
Minimum Repeated START
Set-Up Time
Minimum Hold Time (Repeated)
START Condition
l
l
l
l
l
l
l
l
l
V
IN
= V
SENSE+
/2
(Note 7)
I
2
C Timing Characteristics
f
SCL(MAX)
t
BUF(MIN)
t
SU,STA(MIN)
t
HD,STA(MIN)
400
900
1.3
600
600
600
kHz
µs
ns
ns
ns
t
SU,STO(MIN)
Minimum Set-Up Time for
STOP Condition
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3
Rev. C
LTC2941
ELECTRICAL CHARACTERISTICS
SYMBOL
t
SU,DAT(MIN)
t
HD,DATO
t
Of
PARAMETER
Minimum Data Set-Up Time Input
Data Hold Time Output
Data Output Fall Time
(Notes 6, 7)
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 2)
CONDITIONS
l
l
l
l
MIN
TYP
MAX
100
0
UNITS
ns
µs
µs
ns
t
HD,DATI(MIN)
Minimum Data Hold Time Input
0.3
20 + 0.1
• C
B
0.9
300
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
All currents into pins are positive, all voltages are referenced to
GND unless otherwise specified
Note 3:
I
SUPPLY
= I
SENSE+
+ I
SENSE–
Note 4:
The equivalent charge of an LSB in the accumulated charge
registers (C, D) depends on the value of R
SENSE
and the setting of the
internal prescaling factor M. It is calculated by:
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