19-5210; Rev 3; 4/10
KIT
ATION
EVALU
BLE
AVAILA
Compact, Low-Cost 1S/2S Fuel Gauges
General Description
The MAX17040/MAX17041 are ultra-compact, low-cost,
host-side fuel-gauge systems for lithium-ion (Li+) batter-
ies in handheld and portable equipment. The MAX17040
is configured to operate with a single lithium cell and the
MAX17041 is configured for a dual-cell 2S pack.
The MAX17040/MAX17041 use a sophisticated Li+ bat-
tery-modeling scheme, called ModelGauge™ to track
the battery’s relative state-of-charge (SOC) continuously
over a widely varying charge/discharge profile. Unlike
traditional fuel gauges, the ModelGauge algorithm elim-
inates the need for battery relearn cycles and an exter-
nal current-sense resistor. Temperature compensation
is possible in the application with minimal interaction
between a µC and the device.
A quick-start mode provides a good initial estimate of
the battery’s SOC. This feature allows the IC to be
located on system side, reducing cost and supply
chain constraints on the battery. Measurement and esti-
mated capacity data sets are accessed through an I
2
C
interface. The MAX17040/MAX17041 are available in a
small, 2mm x 3mm, 8-pin TDFN lead-free package.
Features
o
Host-Side or Battery-Side Fuel Gauging
1 Cell (MAX17040)
2 Cell (MAX17041)
o
Precision Voltage Measurement
±12.5mV Accuracy to 5.00V (MAX17040)
±30mV Accuracy to 10.00V (MAX17041)
o
Accurate Relative Capacity (RSOC) Calculated
from ModelGauge Algorithm
o
o
o
o
No Offset Accumulation on Measurement
No Full-to-Empty Battery Relearning Necessary
No Sense Resistor Required
2-Wire Interface
MAX17040/MAX17041
o
Low Power Consumption
o
Tiny, Lead-Free, 8-Pin, 2mm x 3mm TDFN
Package
Ordering Information
PART
MAX17040G+U
MAX17040G+T
MAX17041G+U
TEMP RANGE
-20°C to +70°C
-20°C to +70°C
-20°C to +70°C
PIN-PACKAGE
8 TDFN-EP*
8 TDFN-EP*
8 TDFN-EP*
Applications
Smart Phones
MP3 Players
Digital Still Cameras
Digital Video Cameras
Portable DVD Players
GPS Systems
Handheld and Portable
Applications
MAX17041G+T
-20°C to +70°C
8 TDFN-EP*
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T =Tape and reel.
*EP
= Exposed pad.
ModelGauge is a trademark of Maxim Integrated Products, Inc.
Pin Configuration
TOP VIEW
SDA SCL
8
7
EO
6
SEO
5
Simplified Operating Circuit
150Ω
CELL
V
DD
150Ω
SYSTEM
µP
MAX17040
MAX17041
Li+
PROTECTION
CIRCUIT
MAX17040
MAX17041
SEO
EO
CTG
GND
EP
SDA
SCL
10nF
I
2
C BUS
MASTER
+
1
2
3
4
CTG CELL V
DD
GND
1µF
TDFN
(2mm
×
3mm)
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Compact, Low-Cost 1S/2S Fuel Gauges
MAX17040/MAX17041
ABSOLUTE MAXIMUM RATINGS
Voltage on CTG Pin Relative to V
SS
.......................-0.3V to +12V
Voltage on CELL Pin Relative to V
SS
......................-0.3V to +12V
Voltage on All Other Pins Relative to V
SS
.................-0.3V to +6V
Operating Temperature Range ...........................-40°C to +85°C
Power Dissipation ..........1333mW at +70°C (derate 16.7mW/°C)
Storage Temperature Range .............................-55°C to +125°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
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
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS RECOMMENDED DC OPERATING CONDITIONS
(2.5V
≤
V
DD
≤
4.5V, T
A
= -20°C to +70°C, unless otherwise noted.)
PARAMETER
Supply Voltage
Data I/O Pins
MAX17040 CELL Pin
MAX17041 CELL Pin
SYMBOL
V
DD
(Note 1)
SCL, SDA,
(Note 1)
EO, SEO
V
CELL
V
CELL
(Note 1)
(Note 1)
CONDITIONS
MIN
+2.5
-0.3
-0.3
-0.3
TYP
MAX
+4.5
+5.5
+5.0
+10.0
UNITS
V
V
V
V
DC ELECTRICAL CHARACTERISTICS
(2.5V
≤
V
DD
≤
4.5V, T
A
= -20°C to +70°C, unless otherwise noted. Contact Maxim for V
DD
greater than 4.5V.)
PARAMETER
Active Current
Sleep-Mode Current (Note 2)
SYMBOL
I
ACTIVE
I
SLEEP
CONDITIONS
With on-chip clock in use
With external 32kHz clock
V
DD
= 2.0V
V
DD
= 3.6V at +25°C
Time-Base Accuracy (Note 3)
MAX17040 Voltage-
Measurement Error
MAX17041 Voltage-
Measurement Error
CELL Pin Input Impedance
Input Logic-High:
SCL, SDA, EO, SEO
Input Logic-Low:
SCL, SDA, EO, SEO
Output Logic-Low: SDA
Pulldown Current: SCL, SDA
Input Capacitance: EO
Bus Low Timeout
V
GERR
t
ERR
T
A
= 0°C to +70°C
T
A
= -20°C to +70°C
T
A
= +25°C, V
IN
= V
DD
T
A
= +25°C, 5.0V < V
IN
< 9.0V
5.0 < V
IN
< 9.0
R
CELL
V
IH
V
IL
V
OL
I
PD
C
BUS
t
SLEEP
(Note 4)
1.75
(Note 1)
(Note 1)
I
OL
= 4mA (Note 1)
V
DD
= 4.5V, V
PIN
= 0.4V
0.2
50
2.5
-1
-2
-3
-12.5
-30
-30
-60
15
1.4
0.5
0.4
MIN
TYP
50
40
0.5
1
MAX
75
65
1.0
3
+1
+2
+3
+12.5
+30
+30
+60
M
V
V
V
µA
pF
s
mV
%
UNITS
µA
µA
2
_______________________________________________________________________________________
Compact, Low-Cost 1S/2S Fuel Gauges
ELECTRICAL CHARACTERISTICS: 2-WIRE INTERFACE
(2.5V
≤
V
DD
≤
4.5V, T
A
= -20°C to +70°C.)
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 8)
(Note 9)
(Notes 6, 7)
(Note 6)
(Note 5)
(Note 5)
CONDITIONS
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
µs
µs
µs
µs
µs
µs
ns
ns
ns
µs
ns
pF
pF
MAX17040/MAX17041
Note 1:
All voltages are referenced to V
SS
.
Note 2:
SDA, SCL = V
SS
; EO, SEO idle.
Note 3:
External time base on EO pin must meet this specification.
Note 4:
The MAX17040/MAX17041 enter Sleep mode 1.75s to 2.5s after (SCL < V
IL
) AND (SDA < V
IL
).
Note 5:
f
SCL
must meet the minimum clock low time plus the rise/fall times.
Note 6:
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 7:
This device internally provides a hold time of at least 75ns for the SDA signal (referred to the V
IHMIN
of the SCL signal) to
bridge the undefined region of the falling edge of SCL.
Note 8:
Filters on SDA and SCL suppress noise spikes at the input buffers and delay the sampling instant.
Note 9:
C
B
—total capacitance of one bus line in pF.
_______________________________________________________________________________________
3
Compact, Low-Cost 1S/2S Fuel Gauges
MAX17040/MAX17041
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
SIMPLE C/2 RATE CYCLES
SOC ACCURACY
100
90
80
STATE OF CHARGE (%)
70
60
50
40
30
20
10
0
0
1
2
V
DD
(V)
3
4
5
0
0
REFERENCE SOC:
SOLID LINE
2
4
6
TIME (hr)
8
ERROR (%)
10
12
MAX17040/
MAX17041 SOC:
DASHED LINE
MAX17040 toc02
QUIESCENT CURRENT vs. SUPPLY VOLTAGE
MAX17040 toc01
100
10
8
6
SOC ERROR (%)
4
2
0
-2
-4
-6
-8
-10
QUIESCENT CURRENT (µA)
80
T
A
= +25°C
T
A
= +70°C
60
40
20
T
A
= -20°C
SIMPLE C/4 RATE CYCLES
SOC ACCURACY
100
90
80
STATE OF CHARGE (%)
70
60
50
40
30
20
10
0
0
2
4
6
8 10 12 14 16 18 20 22
TIME (hr)
REFERENCE SOC:
SOLID LINE
ERROR (%)
MAX17040/
MAX17041 SOC:
DASHED LINE
MAX17040 toc03
MAX17040 VOLTAGE ADC ERROR
vs. TEMPERATURE
8
VOLTAGE ADC ERROR (mV)
6
SOC ERROR (%)
4
2
0
-2
-4
-6
-8
-10
-15
-20
-40
-15
10
35
60
85
TEMPERATURE (°C)
15
10
5
0
-5
-10
V
CELL
= 3.6V
V
CELL
= 3.0V
MAX17040 toc04
10
20
V
CELL
= 4.2V
C/2 RATE ZIGZAG PATTERN
SOC ACCURACY
100
90
80
STATE OF CHARGE (%)
70
60
50
40
30
20
10
0
0
4
8
12
TIME (hr)
16
20
22
REFERENCE SOC:
SOLID LINE
MAX17040/MAX17041 SOC:
DASHED LINE
ERROR (%)
MAX17040 toc05
10
8
6
SOC ERROR (%)
4
2
0
-2
-4
-6
-8
-10
4
_______________________________________________________________________________________
Compact, Low-Cost 1S/2S Fuel Gauges
Pin Description
PIN
1
2
3
4
5
NAME
CTG
CELL
V
DD
GND
SEO
FUNCTION
Connect to Ground. Connect to V
SS
during normal operation.
Battery Voltage Input. The voltage of the cell pack is measured through this pin.
Power-Supply Input. 2.5V to 4.5V input range. Connect to system power through a decoupling
network. Connect a 10nF typical decoupling capacitor close to pin.
Ground. Connect to the negative power rail of the system.
External 32kHz Clocking Signal Enable Input. Input to enable external clocking signal on EO pin
with a pullup state. A pulldown state to configure the interrupt feature. External 32kHz clock
enable. Connects logic-low to enable external interrupt.
External 32kHz Clocking Signal. Input for external clocking signal to be the primary system clock.
Configured to implement interrupt feature with a pulldown set on SEO pin.
Serial Clock Input. Input only 2-wire clock line. Connect this pin to the CLOCK signal of the 2-wire
interface. This pin has a 0.2µA typical pulldown to sense disconnection.
Serial Data Input/Output. Open-drain 2-wire data line. Connect this pin to the DATA signal of the
2-wire interface. This pin has a 0.2µA typical pulldown to sense disconnection.
Exposed Pad. Connect PD to ground.
MAX17040/MAX17041
6
7
8
—
EO
SCL
SDA
EP
SDA
t
F
t
LOW
t
R
t
SU:DAT
t
F
t
HD:STA
t
SP
t
R
t
BUF
SCL
t
HD:STA
S
t
HD:DAT
t
SU:STA
Sr
t
SU:STO
P
S
Figure 1. 2-Wire Bus Timing Diagram
Detailed Description
V
DD
BIAS
VOLTAGE
REFERENCE
ADC (VCELL)
CELL
GND
TIME BASE
(32kHz)
EO
Figure 1 shows the 2-wire bus timing diagram, and
Figure 2 is the MAX17040/MAX17041 block diagram.
MAX17040
MAX17041
STATE
MACHINE
(SOC, RATE)
SEO
CTG
ModelGauge Theory of Operation
The MAX17040/MAX17041 use a sophisticated battery
model, which determines the SOC of a nonlinear Li+
battery. The model effectively simulates the internal
dynamics of a Li+ battery and determines the SOC. The
model considers the time effects of a battery caused by
the chemical reactions and impedance in the battery.
The MAX17040/MAX17041 SOC calculation does not
accumulate error with time. This is advantageous
5
IC
GROUND
2-WIRE
INTERFACE
SDA
SCL
Figure 2. Block Diagram
_______________________________________________________________________________________
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