19-4635; 5/09
DS2782
Stand-Alone Fuel Gauge IC
www.maxim-ic.com
GENERAL DESCRIPTION
The DS2782 measures voltage, temperature and
current, and estimates available capacity for
rechargeable lithium ion and lithium-ion polymer
batteries. Cell characteristics and application
parameters used in the calculations are stored in on-
chip EEPROM. The available capacity registers
report a conservative estimate of the amount of
charge that can be removed given the current
temperature, discharge rate, stored charge and
application parameters. Capacity estimation reported
in mAh remaining and percentage of full.
PIN CONFIGURATIONS
APPLICATIONS
Digital Still Cameras
Sub-Notebook Computers
Handheld PC Data Terminals
3G Multimedia Wireless Handsets
FEATURES
Precision Voltage, Temperature, and Current
Measurement System
Accurate Stable Internal Time Base
Absolute and Relative Capacity Estimated from
Coulomb Count, Discharge Rate, Temperature
and Battery Cell Characteristics
Accurate Warning of Low Battery Conditions
Automatic Backup of Coulomb Count and Age
Estimation to Nonvolatile (NV) EEPROM
Gain and Tempco Calibration Allows the Use of
Low-Cost Sense Resistors
24-Byte User EEPROM or 16-Byte User
EEPROM and Unique 64-Bit ID
Industry 2-Wire Interface with Programmable
Slave Address
Tiny 8-Pin TSSOP and 10-TDFN Packages
Embed Easily in Thin Prismatic Cell Packs
TOP MARK
2782+
2782+
2782+
2782+
TYPICAL OPERATING CIRCUIT
ORDERING INFORMATION
PART
DS2782E+
DS2782E+T&R
DS2782G+
DS2782G+T&R
PIN-PACKAGE
8 TSSOP
8 TSSOP
10 TDFN-EP*
10 TDFN-EP*
Note:
To order devices with the unique 64-bit ID option, contact Maxim sales.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
*EP = Exposed pad.
Note:
Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here:
www.maxim-ic.com/errata.
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DS2782
ABSOLUTE MAXIMUM RATINGS
Voltage Range on Any Pin Relative to V
SS
Voltage Range on V
IN
Relative to V
SS
Operating Temperature Range
Storage Temperature Range
Soldering Temperature
-0.3V to +6.0V
-0.3V to (V
DD
+ 0.3V)
-40°C to +85°C
-55°C to +125°C
Refer to the IPC/JEDEC J-STD-020 Specification.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is
not implied. Exposure to the absolute maximum rating conditions for extended periods may affect device reliability.
RECOMMENDED DC OPERATING CHARACTERISTICS
(V
DD
= 2.5V to 4.5V; T
A
= -20°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Supply Voltage
SCL, VIN Voltage Range
SDA, PIO Voltage Range
SYMBOL
V
DD
CONDITIONS
(Note 1)
(Note 1)
(Note 1)
MIN
+2.5
-0.3
-0.3
TYP
MAX
+4.5
+4.5
+5.5
UNITS
V
V
V
DC ELECTRICAL CHARACTERISTICS
(V
DD
= 2.5V to 4.5V; T
A
= -20°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
ACTIVE Current
SLEEP Mode Current
Input Logic-High:
SDA, SCL, PIO
Input Logic-Low:
SDA, SCL, PIO
Output Logic-Low:
SDA, PIO
Pulldown Current:
SDA, SCL, PIO
V
IN
Input Resistance
Bus Low to Sleep Time
Undervoltage SLEEP
Threshold
SYMBOL
I
ACTIVE
I
SLEEP
V
IH
V
IL
V
OL
I
PD
R
IN
t
SLEEP
V
SLEEP
SDA, SCL < V
IL
(Note 2)
(Note 1)
2.40
2.45
CONDITIONS
2.5V
≤
V
DD
≤
4.2V
2.5V
≤
V
DD
≤
4.2V
(Note 1)
(Note 1)
I
OL
= 4mA (Note 1)
V
SDA
, V
SCL
, V
PIO
=
0.4V
15
2.2
2.50
0.2
1.5
0.6
0.4
MIN
TYP
65
1
MAX
95
105
3
UNITS
A
A
V
V
V
A
M
s
V
ELECTRICAL CHARACTERISTICS: TEMPERATURE, VOLTAGE, CURRENT
(V
CC
= 2.5V to 4.5V; T
A
= -20°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Temperature Resolution
Temperature Error
Voltage Resolution
Voltage Full-Scale
Voltage Error
Current Resolution
Current Full-Scale
SYMBOL
T
LSB
T
ERR
V
LSB
V
FS
V
ERR
I
LSB
I
FS
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1.56
±51.2
0
4.88
4.5
±50
CONDITIONS
MIN
TYP
0.125
±3
MAX
UNITS
°C
°C
mV
V
mV
V
mV
DS2782
PARAMETER
Current Gain Error
Current Offset Error
SYMBOL
I
GERR
I
OERR
CONDITIONS
(Note 3)
0°C
≤
T
A
≤
+70°C,
2.5V
≤
V
DD
≤
4.2V
(Note 5)
0°C
≤
T
A
≤
+70°C,
2.5V
≤
V
DD
≤
4.2V
V
SNS
= V
SS
(Notes 4, 5)
V
DD
= 3.8V,
T
A
= +25°C
0°C
≤
T
A
≤
+70°C,
2.5V
≤
VDD
≤
4.2V
-7.82
MIN
TYP
MAX
±1
+12.5
UNITS
% Full-
Scale
V
Vhr/
day
Accumulated Current Offset
q
OERR
-188
+0
±1
±2
±3
Time-Base Error
t
ERR
%
ELECTRICAL CHARACTERISTICS: 2-WIRE INTERFACE
(2.5V
V
DD
4.5V, T
A
= -20C to +70C.)
PARAMETER
SCL Clock Frequency
Bus Free Time Between a
STOP and START Condition
Hold Time (Repeated)
START Condition
Low Period of SCL Clock
High Period of SCL Clock
Setup Time for a Repeated
START Condition
Data Hold Time
Data Setup Time
Rise Time of Both SDA and
SCL Signals
Fall Time of Both SDA and
SCL Signals
Setup Time for STOP
Condition
Spike Pulse Widths
Suppressed by Input Filter
Capacitive Load for Each Bus
Line
SCL, SDA Input Capacitance
SYMBOL
f
SCL
t
BUF
t
HD:STA
t
LOW
t
HIGH
t
SU:STA
t
HD:DAT
t
SU:DAT
t
R
t
F
t
SU:STO
t
SP
C
B
C
BIN
(Note 10)
(Note 11)
(Note 8, 9)
(Note 8)
(Note 7)
CONDITIONS
(Note 6)
MIN
0
1.3
0.6
1.3
0.6
0.6
0
100
20 +
0.1C
B
20 +
0.1C
B
0.6
0
50
400
60
300
300
0.9
TYP
MAX
400
UNITS
kHz
s
s
s
s
s
s
ns
ns
ns
s
ns
pF
pF
EEPROM RELIABILITY SPECIFICATION
(V
CC
= 2.5V to 4.5V; T
A
= -20°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
EEPROM Copy Time
EEPROM Copy Endurance
SYMBOL
t
EEC
N
EEC
T
A
= +50°C
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50,000
CONDITIONS
MIN
TYP
MAX
10
UNITS
ms
cycles
DS2782
Note 1:
All voltages are referenced to V
SS
.
Note 2:
To properly enter sleep mode the application should hold the bus low for longer than the maximum t
SLEEP
.
Note 3:
Factory calibrated accuracy. Higher accuracy can be achieved by in-system calibration by the user.
Note 4:
Accumulation bias register set to 00h.
Note 5:
Parameters guaranteed by design.
Note 6:
Timing must be fast enough to prevent the DS2782 from entering sleep mode due to bus low for period >
t
SLEEP
.
Note 7:
f
SCL
must meet the minimum clock low time plus the rise/fall times.
Note 8:
The maximum t
HD:DAT
has only to be met if the device does not stretch the LOW period (t
LOW
) of the SCL
signal.
Note 9:
This device internally provides a hold time of at least 300 ns for the SDA signal (referred to the VIHmin of
the SCL signal) to bridge the undefined region of the falling edge of SCL.
Note 10:
Filters on SDA and SCL suppress noise spikes at the input buffers and delay the sampling instant.
Note 11:
C
B
– total capacitance of one bus line in pF.
Figure 1. I
2
C Bus Timing Diagram
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DS2782
PIN DESCRIPTION
PIN
TSSOP
1
2
3
4
5
TDFN-EP
1
2, 3
4
5
6
NAME
N.C.
VSS
VIN
V
DD
SDA
FUNCTION
Not Connected.
Pin not connected internally, float or connect to VSS.
Device Ground.
Connect directly to the negative terminal of the battery
cell. Connect the sense resistor between VSS and SNS.
Voltage Sense Input.
The voltage of the battery cell is monitored through
this input pin.
Power-Supply Input.
Connect to the positive terminal of the battery cell
through a decoupling network.
Serial Data Input/Output.
2-Wire data line. Open-drain output driver.
Connect this pin to the DATA terminal of the battery pack. Pin has an
internal pull-down (I
PD
) for sensing disconnection.
Serial Clock Input.
2-Wire clock line. Input only. Connect this pin to the
CLOCK terminal of the battery pack. Pin has an internal pull-down (I
PD
) for
sensing disconnection.
No Connection
Sense Resistor Connection.
Connect to the negative terminal of the
battery pack. Connect the sense resistor between VSS and SNS.
Programmable I/O Pin.
Can be configured as input or output to monitor or
control user-defined external circuitry. Output driver is open drain. This pin
has a weak internal pulldown (I
PD
).
Exposed Pad.
Connect to VSS or leave floating.
6
—
7
8
—
7
8
9
10
EP
SCL
N.C.
SNS
PIO
EP
Figure 2. Block Diagram
VDD
EN
V
POR
BIAS/VREF
Timebase
PIO
VIN
SDA
SCL
2-Wire
Interface
Status
&
Control
Temp
&
Voltage
ADC
EEPROM
Accumulated
Current
Current ADC
15 bit + sign
Rate,
Temperature
Compensation
VSS
SNS
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