The MAX17048/MAX17049 ICs are tiny, micropower cur-
rent fuel gauges for lithium-ion (Li+) batteries in handheld
and portable equipment. The MAX17048 operates with
a single lithium cell and the MAX17049 with two lithium
cells in series.
The ICs use the sophisticated Li+ battery-modeling algo-
rithm ModelGauge™ to track the battery relative state-of-
charge (SOC) continuously over widely varying charge
and discharge conditions. The ModelGauge algorithm
eliminates current-sense resistor and battery-learn cycles
required in traditional fuel gauges. Temperature compen-
sation is implemented using the system microcontroller.
The ICs automatically detect when the battery enters a
low-current state and enters low-power 3µA hibernate
mode, while still providing accurate fuel gauging. The
ICs automatically exit hibernate mode when the system
returns to active state.
On battery insertion, the ICs debounce initial voltage
measurements to improve the initial SOC estimate,
thus allowing them to be located on system side. SOC,
voltage, and rate information is accessed using the I
2
C
interface. The ICs are available in a tiny 0.9mm x 1.7mm,
8-bump wafer-level package (WLP), or a 2mm x 2mm,
8-pin TDFN package.
●
MAX17048: 1 Cell, MAX17049: 2 Cells
●
Precision ±7.5mV/Cell Voltage Measurement
●
ModelGauge Algorithm
• Provides Accurate State-of-Charge
• Compensates for Temperature/Load Variation
• Does Not Accumulate Errors, Unlike Coulomb
Counters
• Eliminates Learning
• Eliminates Current-Sense Resistor
●
Ultra-Low Quiescent Current
•
3μA Hibernate, 23μA Active
• Fuel Gauges in Hibernate Mode
• Automatically Enters and Exits Hibernate Mode
●
Reports Charge and Discharge Rate
●
Battery-Insertion Debounce
• Best of 16 Samples to Estimate Initial SOC
●
Programmable Reset for Battery Swap
• 2.28V to 3.48V Range
●
Configurable Alert Indicator
• Low SOC
• 1% Change in SOC
• Battery Undervoltage/Overvoltage
• VRESET Alert
●
I
2
C Interface
●
8-Bit OTP ID Register (Contact Factory)
Features and Benefits
Applications
●
●
●
●
●
●
●
●
●
Smartphones, Tablets
Smartwatches, Wearables
Bluetooth Headsets
Health and Fitness Monitors
Digital Still, Video, and Action Cameras
Medical Devices
Handheld Computers and Terminals
Wireless Speakers
Home and Building Automation, Sensors
Simple Fuel-Gauge Circuit Diagram
MAX17048
V
DD
ONLY ONE
EXTERNAL
COMPONENT
CELL
CTG
GND
ALRT
SDA
SCL
QSTRT
SYSTEM
µP
Ordering Information
appears at end of data sheet.
ModelGauge is a trademark of Maxim Integrated Products, Inc.
19-6171; Rev 7; 11/16
MAX17048/MAX17049
3μA 1-Cell/2-Cell Fuel Gauge with ModelGauge
Absolute Maximum Ratings
CELL to GND ........................................................-0.3V to +12V
All Other Pins to GND .............................................-0.3V to +6V
Continuous Sink Current, SDA,
ALRT
...............................20mA
Operating Temperature Range ........................... -40°C to +85°C
Storage Temperature Range ............................ -55°C to +125°C
Lead Temperature (TDFN only) (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
(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.) (Note 1)
PARAMETER
Supply Voltage
Fuel-Gauge SOC Reset
(VRESET Register)
Data I/O Pins
SYMBOL
V
DD
V
RST
SCL, SDA,
ALRT
(Note 2)
Configuration range, in 40mV steps
Trimmed at 3V
(Note 2)
Sleep mode, T
A
≤ +50°C
Supply Current
I
DD0
Hibernate mode, reset comparator
disabled (VRESET.Dis = 1)
Hibernate mode, reset comparator
enabled (VRESET.Dis = 0)
I
DD1
Time Base Accuracy
ADC Sample Period
Voltage Error
Voltage-Measurement Resolution
Voltage-Measurement Range
SDA, SCL, QSTRT Input
Logic-High
SDA, SCL, QSTRT Input
Logic-Low
SDA,
ALRT
Output
Logic-Low
SDA, SCL Bus
Low-Detection Current
Bus Low-Detection Timeout
V
IH
V
IL
V
OL
I
PD
t
SLEEP
I
OL
= 4mA
V
SDA
= V
SCL
= 0.4V (Note 5)
(Note 6)
1.75
0.2
MAX17048: V
DD
pin
MAX17049: CELL pin
2.5
5
1.4
0.5
0.4
0.4
2.5
V
ERR
t
ERR
Active mode
Active, hibernate modes (Note 3)
Active mode
Hibernate mode
V
CELL
= 3.6V, T
A
= +25°C (Note 4)
-7.5
-20
1.25
5
10
-3.5
CONDITIONS
MIN
2.5
2.28
2.85
-0.3
0.5
3
4
23
±1
250
45
+7.5
+20
40
+3.5
%
ms
s
mV/cell
mV/cell
V
V
V
V
µA
s
3.0
TYP
MAX
4.5
3.48
3.15
+5.5
2
5
µA
UNITS
V
V
V
V
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Maxim Integrated
│
2
MAX17048/MAX17049
3μA 1-Cell/2-Cell Fuel Gauge with ModelGauge
Electrical Characteristics (I
2
C INTERFACE)
(2.5V < V
DD
< 4.5V, T
A
= -20°C to +70°C, unless otherwise noted.) (Note 1)
PARAMETER
SCL Clock Frequency
Bus Free Time Between a
STOP and START Condition
START Condition (Repeated)
Hold Time
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
B,IN
(Note 11)
(Note 12)
(Notes 9, 10)
(Note 9)
(Note 8)
(Note 7)
CONDITIONS
MIN
0
1.3
0.6
1.3
0.6
0.6
0
100
20 + 0.1CB
20 + 0.1CB
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
Note 1:
Specifications are 100% tested at T
A
= +25°C. Limits over the operating range are guaranteed by design and
characterization.
Note 2:
All voltages are referenced to GND.
Note 3:
Test is performed on unmounted/unsoldered parts.
Note 4:
The voltage is trimmed and verified with 16x averaging.
Note 5:
This current is always present.
Note 6:
The IC enters shutdown mode after SCL < V
IL
and SDA < V
IL
for longer than 2.5s.
Note 7:
Timing must be fast enough to prevent the IC from entering sleep mode due to bus low for period > t
SLEEP
.
Note 8:
f
SCL
must meet the minimum clock low time plus the rise/fall times.
Note 9:
The maximum t
HD:DAT
has to be met only if the device does not stretch the low period (t
LOW
) of the SCL signal.
Note 10:
This device internally provides a hold time of at least 100ns for the SDA signal (referred to the V
IH,MIN
of the SCL signal) to
bridge the undefined region of the falling edge of SCL.
Note 11:
Filters on SDA and SCL suppress noise spikes at the input buffers and delay the sampling instance.
Note 12:
C
B
is total capacitance of one bus line in pF.
www.maximintegrated.com
Maxim Integrated
│
3
MAX17048/MAX17049
3μA 1-Cell/2-Cell Fuel Gauge with ModelGauge
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
t
SU:STA
t
SU:STO
S
t
HD:DAT
Sr
P
S
Figure 1. I
2
C Bus Timing Diagram
Typical Operating Characteristics
QUIESCENT CURRENT vs. SUPPLY
VOLTAGE (HIBERNATE MODE)
MAX17048 toc01
(T
A
= +25°C, battery is Sanyo UF504553F, unless otherwise noted.)
QUIESCENT CURRENT vs. SUPPLY
VOLTAGE (ACTIVE MODE)
MAX17048 toc02
QUIESCENT CURRENT (µA)
QUIESCENT CURRENT (µA)
4
3
VOLTAGE ADC ERROR (mV/CELL)
T
A
= +70°C
35
30
25
20
15
10
5
T
A
= +25°C
T
A
= -20°C
T
A
= +70°C
15
10
5
0
-5
-10
-15
-20
-20
-5
10
25
40
55
V
CELL
= 2.5V
V
CELL
= 3.6V
V
CELL
= 4.5V
T
A
= -20°C
2
1
0
T
A
= +25°C
2.5
3.0
3.5
V
CELL
(V)
4.0
4.5
0
2.5
3.0
3.5
V
CELL
(V)
4.0
4.5
70
TEMPERATURE (°C)
0.50
C
RATE
(%/Hr)
0.25
0
CURRENT (I_BATT mA, I_DD uA)
0.75
MAX17048 C
RATE
MAX17048 toc04
1.00
C
RATE
ACCURACY
600
500
400
300
200
100
0
-100
ENTER HIBERNATE MODE
AUTOMATICALLY
MAX17048 toc05
4.00
3.95
V
BATT
3.90
3.85
V
BATT
(V)
-0.25
-0.50
-0.75
-1.00
-4
I
BATT
3.80
3.75
3.70
MEASURED C
RATE
-2
0
2
TIME (Hr)
4
6
8
I
DD1
0
5
10
TIME (min)
I
DD0
15
20
3.65
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Maxim Integrated
│
4
MAX17048 toc03
5
40
20
VOLTAGE ADC ERROR vs. TEMPERATURE
MAX17048/MAX17049
3μA 1-Cell/2-Cell Fuel Gauge with ModelGauge
Typical Operating Characteristics (continued)
(T
A
= +25°C, battery is Sanyo UF504553F, unless otherwise noted.)
1. Introduction
Electronic scales are gradually replacing traditional measuring tools like springs and balances in everyday life, such as electronic price computing scales and electronic weigh...[详细]
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