19-4634; 5/09
DS2780
Standalone Fuel Gauge IC
www.maxim-ic.com
GENERAL DESCRIPTION
The DS2780 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.
FEATURES
Precision Voltage, Temperature, and Current
Measurement System
Internal Time Base is Accurate and Temperature
Stable
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 Battery/Application Parameter EEPROM
16-Byte User EEPROM
Unique ID and Multidrop 1-Wire
Interface
Tiny 8-pin TSSOP & 10-pin TDFN Package
Embeds Easily in Battery Packs Using Thin
Prismatic Cells
APPLICATIONS
Digital Still Cameras
Sub-Notebook Computers
Handheld PC Data Terminals
3G Multimedia Wireless Handsets
TYPICAL OPERATING CIRCUIT
PK+
PIN CONFIGURATION
DS2780
DATA
150
DQ
PIO
NC
SNS
5.6V
500
1K
5
8
1
7
TSSOP-8
4
VDD
3
VIN
6
OVD
2
VSS
0.1uF
Protection
Circuit
1 Cell
Li-Ion
Battery
PK-
RSNS
ORDERING INFORMATION
PART
DS2780E
DS2780E/T&R
DS2780E+
DS2780E+T&R
DS2780G+
DS2780G+T&R
MARKING
2780
2780
2780
2780
2780
2780
PACKAGE INFORMATION
TSSOP
TSSOP Tape-and-Reel
TSSOP
TSSOP Tape-and-Reel
TDFN
TDFN Tape-and-Reel
+Denotes lead(Pb)-free/RoHS-compliant package.
1-Wire is a registered trademark of Maxim Integrated Products, Inc.
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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DS2780 Standalone Fuel Gauge IC
ABSOLUTE MAXIMUM RATINGS
Voltage Range on Any Pin Relative to VSS
Voltage on VIN Relative to VSS
Operating Temperature Range
Storage Temperature Range
Soldering Temperature (10s)
-0.3V to +6.0V
-0.3V to (V
DD
+ 0.3V)
-40°C to +85°C
-55°C to +125°C
See JEDEC J-STD-020
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
(VDD = 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
OVD Voltage
DQ, PIO Voltage Range
SYMBOL
VDD
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
(VDD = 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: DQ, PIO
Input Logic Low: DQ, PIO
Output Logic Low: DQ, PIO
Pulldown Current: DQ, PIO
Input Logic High: OVD
Input Logic Low: OVD
VIN Input Resistance
DQ Capacitance
DQ SLEEP Timeout
Undervoltage SLEEP
Threshold
SYMBOL
I
ACTIVE
I
SLEEP
V
IH
V
IL
V
OL
I
PD
V
IH
V
IL
R
IN
C
DQ
t
SLEEP
V
SLEEP
CONDITIONS
2.5V
≤
VDD
≤
4.2V
2.5V
≤
VDD
≤
4.2V
(Note 1)
(Note 1)
I
OL
= 4mA (Note 1)
V
DQ
, V
PIO
= 0.4V
(Note 1)
(Note 1)
15
DQ < V
IL
(Note 5)
(Note 1)
1.5
2.40
50
2.0
2.45
2.5
2.50
1.5
0.6
0.4
0.2
VDD –
0.2
VSS + 0.2
MIN
TYP
65
1
MAX
95
105
3
UNITS
µA
µA
V
V
V
µA
V
V
M
pF
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
SYMBOL
T
LSB
T
ERR
V
LSB
V
FS
V
ERR
I
LSB
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1.56
0
4.88
4.992
±50
CONDITIONS
MIN
TYP
0.125
±3
MAX
UNITS
°C
°C
mV
V
mV
µV
DS2780 Standalone Fuel Gauge IC
PARAMETER
Current Full-Scale
Current Gain Error
Current Offset Error
SYMBOL
I
FS
I
GERR
I
OERR
(Note 2)
0°C
≤
T
A
≤
+70°C,
2.5V
≤
VDD
≤
4.2V
(Note 4)
0°C
≤
T
A
≤
+70°C,
2.5V
≤
VDD
≤
4.2V
VSNS = VSS, (Notes 3,
4)
VDD = 3.8V, T
A
= +25°C
0°C
≤
T
A
≤
+70°C,
2.5V
≤
VDD
≤
4.2V
-7.82
CONDITIONS
MIN
TYP
MAX
±51.2
±1
+12.5
UNITS
mV
% Full-
Scale
µV
µVhr/
day
Accumulated Current Offset
q
OERR
-188
+0
±1
±2
±3
Timebase Error
t
ERR
%
ELECTRICAL CHARACTERISTICS: 1-WIRE INTERFACE, STANDARD
(V
CC
= 2.5V to 4.5V, T
A
= -20°C to +70°C.)
PARAMETER
Time Slot
Recovery Time
Write-0 Low Time
Write-1 Low Time
Read Data Valid
Reset Time High
Reset Time Low
Presence Detect High
Presence Detect Low
SYMBOL
t
SLOT
t
REC
t
LOW0
t
LOW1
t
RDV
t
RSTH
t
RSTL
t
PDH
t
PDL
480
480
15
60
960
60
240
CONDITIONS
MIN
60
1
60
1
120
15
15
TYP
MAX
120
UNITS
s
s
s
s
s
s
s
s
s
ELECTRICAL CHARACTERISTICS: 1-WIRE INTERFACE, OVERDRIVE
(V
CC
= 2.5V to 4.5V, T
A
= -20°C to +70°C.)
PARAMETER
Time Slot
Recovery Time
Write-0 Low Time
Write-1 Low Time
Read Data Valid
Reset-Time High
Reset-Time Low
Presence-Detect High
Presence-Detect Low
SYMBOL
t
SLOT
t
REC
t
LOW0
t
LOW1
t
RDV
t
RSTH
t
RSTL
t
PDH
t
PDL
48
48
2
8
80
6
24
CONDITIONS
MIN
6
1
6
1
16
2
2
TYP
MAX
16
UNITS
s
s
s
s
s
s
s
s
s
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DS2780 Standalone Fuel Gauge IC
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
50,000
CONDITIONS
MIN
TYP
MAX
10
UNITS
ms
cycles
Note 1:
All voltages are referenced to VSS.
Note 2:
Factory calibrated accuracy. Higher accuracy can be achieved by in-system calibration by the user.
Note 3:
Accumulation bias register set to 00h.
Note 4:
Parameters guaranteed by design.
Note 5:
The application must wait for the maximum DQ SLEEP Timeout to confirm that the IC has entered sleep
mode.
PIN DESCRIPTION
NAME
TSSOP
PIN
TDFN
PIN
FUNCTION
NC
VSS
VIN
VDD
DQ
1
2
3
4
5
1
2, 3
4
5
6
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.
Data Input/Output.
1-Wire data line. Open-drain output driver. Connect this pin to the
DATA terminal of the battery pack. This pin has a weak internal pulldown (I
PD
) for
sensing pack disconnection from host or charger.
1-Wire Bus Speed Control.
Input logic level selects the speed of the 1-Wire bus.
Logic 1 selects overdrive (OVD) and Logic 0 selects standard timing (STD). On a
multidrop bus, all devices must operate at the same speed.
Not Connected.
Pin not connected internally, float or connect to VSS.
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 an weak
internal pulldown (I
PD
).
Exposed Pad.
Connect to VSS or leave floating. (Only present on TDFN package)
OVD
NC
SNS
PIO
PAD
6
—
7
8
—
7
8
9
10
PAD
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DS2780 Standalone Fuel Gauge IC
Figure 1. Block Diagram
DETAILED DESCRIPTION
The DS2780 operates directly from 2.5V to 4.5V and supports single cell Lithium-ion battery packs. As shown in
Figure 2, the DS2780 accommodates multicell applications by adding a voltage regulator for VDD and voltage
divider for VIN. Nonvolatile storage is provided for cell compensation and application parameters. Host side
development of fuel-gauging algorithms is eliminated. On-chip algorithms and convenient status reporting of
operating conditions reduce the serial polling required of the host processor. For 2-cell applications, the DS2781 is
recommended, since it includes a voltage regulator and accepts VIN up to 10V.
Additionally, 16 bytes of EEPROM memory are made available for the exclusive use of the host system and/or
pack manufacturer. The additional EEPROM memory can be used to facilitate battery lot and date tracking and
non-volatile storage of system or battery usage statistics.
A Dallas 1-Wire interface provides serial communication at the standard 16kbps or overdrive 140kbps speeds. It
allows access to data registers, control registers and user memory. A unique, factory programmed 64-bit
registration number (8-bit family code + 48-bit serial number + 8-bit CRC) assures that no two parts are alike and
enables absolute traceability. The Dallas 1-Wire interface on the DS2780 supports multidrop capability so that
multiple slave devices may be addressed with a single pin.
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