LTC2941
Battery Gas Gauge
with I
2
C Interface
FeaTures
n
n
n
n
n
n
n
n
n
n
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/I
2
C 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 and
ThinSOT and Bat-Track are trademarks of Linear Technology Corporation. All other 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
2941fb
For more information
www.linear.com/LTC2941
1
LTC2941
absoluTe maximum raTings
Supply Voltage (SENSE
+
) ............................. –0.3V to 6V
SCL, SDA,
AL/CC
......................................... –0.3V to 6V
SENSE
–
.................................. –0.3V to (V
SENSE+
+ 0.3V)
(Notes 1, 2)
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
NC
1
2
3
4
9
8
7
6
5
SENSE
–
AL/CC
SDA
NC
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
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
(http://www.linear.com/product/LTC2941#orderinfo)
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
LTC2941CDCB#TRPBF
LTC2941IDCB#TRPBF
TAPE AND REEL
LTC2941CMS8E#TRPBF
LTC2941IMS8E#PBF
LTC2941IMS8E#TRPBF
LTGVY
8-Lead Plastic MSOP
–40°C to 85°C
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
2
2941fb
For more information
www.linear.com/LTC2941
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
2941fb
For more information
www.linear.com/LTC2941
3
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)
t
HD,DATI(MIN)
Minimum Data Hold Time Input
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
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:
50mΩ M
q
LSB
=
0.085mAh •
•
R
SENSE
128
See Choosing R
SENSE
and Coulomb Counter Prescaler M section for more
information.
1mAh = 3.6A • s = 3.6C (coulomb), 0.085mAh = 306mC.
Note 5:
Deviation of q
LSB
from its nominal value.
Note 6:
C
B
= capacitance of one bus line in pF (10pF ≤ C
B
≤ 400pF).
Note 7:
Guaranteed by design, not subject to test.
Timing Diagram
t
of
SDA
t
SU, DAT
t
HD, DATO,
t
HD, DATI
t
SU, STA
t
HD, STA
t
SU, STO
t
BUF
2941 F01
SCL
t
HD, STA
START
CONDITION
REPEATED START
CONDITION
STOP
CONDITION
START
CONDITION
Figure 1. Definition of Timing on I
2
C Bus
4
2941fb
For more information
www.linear.com/LTC2941
LTC2941
Typical perFormance characTerisTics
Total Charge Error
vs Differential Sense Voltage
3
2
CHARGE ERROR (%)
1
0
–1
–2
–3
0.1
CHARGE ERROR (%)
1.00
0.75
CHARGE ERROR (%)
0.50
0.25
0
Total Charge Error
vs Supply Voltage
1.00
0.75
0.50
0.25
0
–0.25
–0.50
–0.75
Total Charge Error vs Temperature
–0.25
–0.50
–0.75
–1.00
2.5
3.0
3.5
V
SENSE
= –50mV
V
SENSE
= –10mV
4.0 4.5
5.0
V
SENSE+
(V)
5.5
6.0
V
SENSE+
= 2.7V
V
SENSE+
= 4.2V
1
V
SENSE
(mV)
2941 G01
10
100
–1.00
–50
V
SENSE
= –50mV
V
SENSE
= –10mV
–25
25
50
0
TEMPERATURE (°C)
75
100
2941 G03
2941 G02
Supply Current vs Supply Voltage
100
90
80
70
60
50
40
2.5
0
T
A
= 25°C
T
A
= –40°C
T
A
= 85°C
I
SHUTDOWN
(µA)
2.0
Shutdown Supply Current
vs Supply Voltage
1.5
I
SUPPLY
(µA)
1.0
0.5
T
A
= 25°C
T
A
= –40°C
T
A
= 85°C
2.5
3.0
3.5
4.0 4.5
5.0
V
SENSE+
(V)
5.5
6.0
3.0
3.5
4.0 4.5
5.0
V
SENSE+
(V)
5.5
6.0
2941 G04
2941 G05
2941fb
For more information
www.linear.com/LTC2941
5
玄铁RISC-V活动专区
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
