DS2751
Multichemistry Battery
Fuel Gauge
www.maxim-ic.com
FEATURES
§
Available in Two Configurations
- Internal 25mW Sense Resistor
- External User-Selectable Sense Resistor
Current Measurement
- 12-Bit Bidirectional Measurement
- Internal Sense Resistor Configuration:
0.625mA LSB and ±1.9A Dynamic Range
- External Sense Resistor Configuration:
15.625mV LSB and ±64mV Dynamic
Range
Current Accumulation
- Internal Sense Resistor: 0.25mAhr LSB
- External Sense Resistor: 6.25mVhr LSB
Voltage Measurement with 4.88mV
Resolution
Temperature Measurement Using Integrated
Sensor with 0.125°C Resolution
32 Bytes of Lockable EEPROM
16 Bytes of General-Purpose SRAM
Dallas 1-Wire
®
Interface with Unique 64-Bit
Device Address
Supports 1-Cell Li+/Polymer or 3-Cell Ni
Battery Packs
3mm Dimension of 8-Pin TSSOP Package
Allows Mounting on Side of Thin Li+ and
Li+/Polymer Cells
Low Power Consumption:
- Active Current: 60mA (typ), 90mA (max)
- Sleep Current:
1mA (typ), 2mA (max)
PIN CONFIGURATION
V
IN
V
SS
PIO
V
DD
1
2
2
3
2
4
8
7
6
5
DQ
SNS
IS2
IS1
§
DS2751E
8-Pin TSSOP Package
PIN DESCRIPTION
V
IN
V
SS
PIO
V
DD
IS1
IS2
SNS
DQ
Voltage-Sense Input
Device Ground
Programmable I/O Pin
Power-Supply Input (2.5V to 5.5V)
Current-Sense Input
Current-Sense Input
Sense Resistor Connection
Data Input/Output
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§
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ORDERING INFORMATION
PART
DS2751E
DS2751E-025
DS2751E/T&R
DS2751E-025/T&R
MARKING
2751E
2751R
2751E
2751R
TEMP RANGE
-20°C to +70°C
-20°C to +70°C
-20°C to +70°C
-20°C to +70°C
DESCRIPTION
8-Pin TSSOP, External Sense Resistor
8-Pin TSSOP, 25mW Sense Resistor
DS2751E on Tape-and-Reel
DS2751E-025 on Tape-and-Reel
1-Wire is a registered trademark of Dallas Semiconductor.
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050803
DS2751
DESCRIPTION
The DS2751 multichemistry battery fuel gauge is a data-acquisition and information-storage device
tailored for cost-sensitive and space-constrained 1-cell Li+/polymer or 3-cell Ni battery-pack
applications. The DS2751 provides the key hardware components required to accurately estimate
remaining capacity by integrating low-power, precision measurements of temperature, voltage, current,
and current accumulation, as well as nonvolatile (NV) data storage, into the small footprint of a 3.0mm x
4.4mm 8-pin TSSOP package.
Through its 1-Wire interface, the DS2751 gives the host system read/write access to status and control
registers, instrumentation registers, and general-purpose data storage. Each device has a unique factory-
programmed 64-bit net address that allows it to be individually addressed by the host system, supporting
multibattery operation.
The DS2751 performs temperature, voltage, and current measurement to a resolution sufficient to support
process-monitoring applications such as battery charge control and remaining capacity estimation.
Temperature is measured using an on-chip sensor, eliminating the need for a separate thermistor.
Bidirectional current measurement and accumulation are accomplished using either an internal 25mW
sense resistor or an external device. The DS2751 also features a programmable I/O pin that allows the
host system to sense and control other electronics in the pack, including switches, vibration motors,
speakers, and LEDs.
Three types of memory are provided on the DS2751 for battery information storage: EEPROM, lockable
EEPROM, and SRAM. EEPROM memory saves important battery data in true NV memory that is
unaffected by severe battery depletion, accidental shorts, or ESD events. Lockable EEPROM becomes
ROM when locked to provide additional security for unchanging battery data. SRAM provides
inexpensive storage for temporary data.
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DS2751
ABSOLUTE MAXIMUM RATINGS*
Voltage on PIO Pin, Relative to V
SS
Voltage on All Other Pins, Relative to V
SS
Continuous Internal Sense Resistor Current
Pulsed Internal Sense Resistor Current
Operating Temperature Range
Storage Temperature Range
Soldering Temperature
-0.3V to +12V
-0.3V to +6V
±2.5A
±50A
for <100µs/s, <1000 Pulses
-40°C to +85°C
-55°C to +125°C
See J-STD-020A Specification
*
This is a stress rating only and functional operation of the device at these or any other conditions above
those indicated in the operation sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS
(T
A
= 2.5V
£
V
DD
£
5.5V, -20°C to +70°C.)
PARAMETER
SYMBOL
CONDITIONS
Supply Voltage
V
DD
(Note 1)
Data Pin
DQ
(Note 1)
V
DD
³
4.2V (Notes 1, 2)
V
IN
Pin
V
IN
2.5V
<
V
DD
<
4.2V
(Notes 1, 2)
MIN
2.5
-0.3
-0.3
TYP
MAX
5.5
+5.5
+4.5
V
DD
+
0.3
UNITS
V
V
V
V
DC ELECTRICAL CHARACTERISTICS
(T
A
= 2.5V
£
V
DD
£
5.5V, -20°C to +70°C.)
PARAMETER
SYMBOL
CONDITIONS
DQ = V
DD
,
Active Current
I
ACTIVE
normal operation
DQ = 0V,
Sleep-Mode Current
I
SLEEP
no activity
Input Logic High:
V
IH
(Note 1)
DQ, PIO
Input Logic Low:
V
IL
(Note 1)
DQ, PIO
Output Logic Low:
I
OL
= 4mA (Note 1)
V
OL
DQ, PIO
DQ Pulldown Current
I
PD
Input Resistance: V
IN
R
IN
Internal Current-Sense
R
SNS
+25°C
Resistor
DQ Low-to-Sleep
t
SLEEP
Time
Undervoltage Detect
V
UV
(Note 1)
Undervoltage Delay
T
UVD
MIN
TYP
60
1
1.5
0.4
0.4
1
5
20
2.2
2.5
90
2.6
100
2.7
110
25
30
MAX
90
2
UNITS
mA
mA
V
V
V
mA
MW
mW
s
V
ms
3 of 19
DS2751
ELECTRICAL CHARACTERISTICS: TEMPERATURE, VOLTAGE, CURRENT
(T
A
= 2.5V
£
V
DD
£
5.5V, -20°C to +70°C.)
PARAMETER
SYMBOL
CONDITIONS
Temperature Resolution
T
LSB
Temperature Full-Scale
T
FS
Magnitude
Temperature Error
T
ERR
(Note 3)
Voltage Resolution
V
LSB
Voltage Full-Scale
V
FS
(Note 4)
Magnitude
Voltage Offset Error
V
OERR
(Note 5)
Voltage Gain Error
Current Resolution
Current Full-Scale
Magnitude
Current Offset Error
Current Gain Error
Accumulated Current
Resolution
Current Sampling
Frequency
Internal Timebase
Accuracy
V
GERR
I
LSB
I
FS
I
OERR
I
GERR
q
CA
f
SAMP
t
ERR
0°C to +50°C
(Note 11)
-20°C to +70°C
(Note 6)
(Note 7)
(Notes 6, 7)
(Note 8)
(Note 9)
(Notes 6, 10)
(Note 7)
(Note 6)
(Note 7)
0.625
15.625
2.56
64
1
3
1
0.25
6.25
1456
±1
±3
±5
MIN
127
4.88
4.5
1
3
±3
TYP
0.125
MAX
UNITS
°C
°C
°C
mV
V
LSB
%V
reading
mA
m
V
A
mV
LSB
%I
reading
mAhr
µVhr
Hz
%
1.9
ELECTRICAL CHARACTERISTICS—1-WIRE INTERFACE
(T
A
= 2.5V
£
V
DD
£
5.5V, -20°C to +70°C.)
PARAMETER
SYMBOL
CONDITIONS
Time Slot
t
SLOT
Recovery Time
t
REC
Write 0 Low Time
t
LOW0
Write 1 Low Time
t
LOW1
Read Data Valid
t
RDV
Reset Time High
t
RSTH
Reset Time Low
t
RSTL
Presence-Detect High
t
PDH
Presence-Detect Low
t
PDL
DQ Capacitance
C
DQ
MIN
60
1
60
1
480
480
15
60
TYP
MAX
120
119
15
15
960
60
240
60
UNITS
m
s
m
s
m
s
m
s
m
s
m
s
m
s
m
s
m
s
pF
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DS2751
EEPROM RELIABILITY SPECIFICATION
(T
A
= 2.5V
£
V
DD
£
5.5V, -20°C to +70°C.)
PARAMETER
SYMBOL
CONDITIONS
Copy to EEPROM Time
t
EEC
EEPROM Copy
(Note 12)
N
EEC
Endurance
MIN
25,000
TYP
2
MAX
10
UNITS
ms
cycles
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note 10:
Note 11:
Note 12:
All voltages are referenced to V
SS
.
Operating V
IN
> 4.5V relative to V
SS
, or V
IN
> V
DD
+ 0.3V can induce errors in voltage,
temperature, or current measurements.
Self heating due to output pin loading and sense resistor power dissipation can alter the
reading from ambient conditions.
Although the Voltage Register is large enough to report values larger than 4.75V, the internal
compensation for circuit variations can reduce the maximum reportable voltage to as low as
4.75V.
Voltage offset measurement is with respect to 4.35V at +25°C.
Internal current-sense resistor configuration.
External current-sense resistor configuration.
The Current Register supports measurement magnitudes up to 2.56A using the internal sense-
resistor option and 64mV with the external resistor option. Compensation of the internal
sense-resistor value for process and temperature variation may reduce the maximum
reportable magnitude to 1.9A.
Current offset error null to ±1 LSb typically requires a one time 3.5s in-system calibration by
user.
Current gain-error specification applies to gain error in converting the voltage difference at
IS1 and IS2, and excludes any error remaining after the DS2751 compensates for the internal
sense-resistor’s temperature coefficient of 3700ppm/°C to an accuracy of
±500ppm/°C.
The
DS2751 does not compensate for external sense resistor characteristics, and any error terms
arising from the use of an external sense resistor should be taken into account when
calculating total current measurement error.
Typical value for t
ERR
valid at 3.6V and +25°C.
Four year data retention at +70°C.
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