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MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
General Description
Benefits and Features
The MAX17261 is an ultra-low power fuel gauge IC which
implements the Maxim ModelGauge™ m5 algorithm. The
IC monitors a multiple-series cell battery pack with an external resistor divider.
● ModelGauge m5 EZ
• No Characterization Required for EZ Performance
• Robust Against Battery Variation
• Eliminates Error Near Empty Voltage
• Eliminates Coulomb Counter Drift
• Compensates for Age, Current, and Temperature
• Does Not Require Empty, Full, or Idle States
The ModelGauge m5 EZ algorithm makes fuel gauge implementation easy by eliminating battery characterization
requirements and simplifying host software interaction. The algorithm provides tolerance against battery diversity for most lithium batteries and applications.
The algorithm combines the short-term accuracy and linearity of a coulomb counter with the long-term stability of
a voltage-based fuel gauge, along with temperature compensation to provide industry-leading fuel gauge accuracy. The IC automatically compensates for cell-aging, temperature, discharge rate, and provides accurate state-ofcharge (SOC) in percentage (%) and remaining capacity
in milliampere-hours (mAh) over a wide range of operating conditions. As the battery approaches the critical region near empty, the algorithm invokes a special correction mechanism that eliminates any error. The IC provides
accurate estimation of time-to-empty and time-to-full and
provides three methods for reporting the age of the battery: reduction in capacity, increase in battery resistance,
and cycle odometer.
The IC provides precision measurements of current, voltage, and temperature. The temperature of the battery
pack is measured using an internal temperature sensor or
external thermistor. A 2-wire I2C interface provides access
to data and control registers. The IC is available in a tiny
lead-free 0.4mm pitch, 1.5mm x 1.5mm, 9-pin WLP package and 3mm x 3mm, 14-pin TDFN package.
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Low 5.1μA Operating Current
Monitors Multiple-Cell Battery Pack
Wide Sense Resistor Range: 1mΩ to 1000mΩ
PCB Metal Sensing + Temperature Compensation
Supports Li+ and Variants Including LiFePO4
Thermistor or ±1°C Internal Temperature
Dynamic Power Estimates Power Capability During
Discharge
Time-to-Empty and Time-to-Full Estimation
Predicts Remaining Capacity Under Theoretical Load
No Calibration Required
Alert Indicator for Voltage, SOC, Temperature,
Current and 1% SOC Change
Ordering Information appears at end of data sheet.
Simple Fuel Gauge Circuit Diagram
SYSPWR
3~5V
REG
BATT
0.1µF
REG
MAX17261
Applications
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Tablets, 2-in-1 Laptops
Digital Still, Video, and Action Cameras
Medical Devices
Handheld Computers and Terminals
Financial Terminals
Mobile Printers
Augmented/Virtual Reality Devices
Robots
E-Bikes
Battery Backups
Wireless Speakers
ModelGauge is a trademark of Maxim Integrated Products, Inc.
19-100318; Rev 0; 5/18
0.47µF
CELLX
ALRT
SDA
SCL
PROTECTION
CIRCUIT
TH
CSPL (TDFN)
EP (TDFN)
GND
CSN
10kΩ
NTC
RSENSE
SYSGND
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
TABLE OF CONTENTS
General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Benefits and Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Simple Fuel Gauge Circuit Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
WLP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
TDFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Typical Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Pin Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
TDFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
WLP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Functional Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Detailed Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
ModelGauge m5 EZ Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Standard Register Formats. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
ModelGauge m5 EZ Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
DesignCap Register (18h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
VEmpty Register (3Ah). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
ModelCfg Register (DBh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
IChgTerm Register (1Eh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Config Register (1Dh) and Config2 Register (BBh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
ModelGauge m5 EZ Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
ModelGauge m5 Algorithm Output Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
RepCap Register (05h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
RepSOC Register (06h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
FullCapRep Register (10h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
TTE Register (11h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
TTF Register (20h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Cycles Register (17h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Status Register (00h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Analog Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Voltage Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
VCell Register (09h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
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Maxim Integrated | 2
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
TABLE OF CONTENTS (CONTINUED)
AvgVCell Register (19h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
MaxMinVolt Register (1Bh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Current Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Current Register (0Ah). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
AvgCurrent Register (0Bh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
MaxMinCurr Register (1Ch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Temperature Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Temp Register (08h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
AvgTA Register (16h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
MaxMinTemp Register (1Ah) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
DieTemp Register (034h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Power Register (B1h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
AvgPower Register (B3h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Alert Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
VAlrtTh Register (01h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
TAlrtTh Register (02h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
SAlrtTh Register (03h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
IAlrtTh Register (B4h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Serial Number Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
ModelGauge m5 Memory Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Layout Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Typical Application Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
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Maxim Integrated | 3
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
LIST OF FIGURES
Figure 1. ModelGauge m5 EZ Configuration Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 2. ModelGauge m5 EZ Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 3. MAX17261 Layout Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 4. Low-Side Current Measurement Typical Applications Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Figure 5. Multiple-Series Battery Typical Applications Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
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Maxim Integrated | 4
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
LIST OF TABLES
Table 1. ModelGauge m5 EZ Performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 2. ModelGauge m5 Register Standard Resolutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 3. VEmpty (3Ah) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 4. ModelCFG (DBh) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 5. Config (1Dh) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 6. Config2 (BBh) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 7. Status (00h) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 8. MaxMinVolt (1Bh) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 9. Current Measurement Range and Resolution vs. Sense Resistor Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 10. MaxMinCurr (1Ch) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 11. MaxMinTemp (1Ah) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 12. VAlrtTh (01h) Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 13. TAlrtTh (02h) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 14. SAlrtTh (03h) Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 15. IAlrtTh (B4h) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 16. Serial Number Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 17. ModelGauge m5 Register Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
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Maxim Integrated | 5
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Absolute Maximum Ratings
BATT to GND ........................................................... -0.3V to +6V
ALRT to GND ......................................................... -0.3V to +17V
REG to GND.......................................................... -0.3V to +2.2V
TH to GND............................................... -0.3 V to VBATT + 0.3 V
CELLX to GND .......................................... -0.3V to VBATT + 0.3V
CSN to GND .............................................. -0.3V to VBATT + 0.3V
CSPL to GND ........................................................ -0.3V to +0.3V
SDA, SCL to GND .................................................... -0.3V to +6V
SW to GND .................................................... -0.3 to VBATT + 0.3
Operating Temperature Range .............................-40°C to +85°C
Junction Temperature ....................................................... +150°C
Storage Temperature Range ..............................-55°C to +125°C
Soldering Temperature (reflow) ........................................ +260°C
Continuous Source Current for TH ........................................1mA
Continuous Sink Current for SDA, ALRT .............................20mA
Lead Temperature (soldering 10s).................................... +300ºC
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.
Package Information
WLP
Package Code
W91G1+2
Outline Number
21-100168
Land Pattern Number
Refer to Application Note 1891
Thermal Resistance, Four-Layer Board:
Junction to Ambient (θJA)
83.98ºC/W
Junction to Case (θJC)
NA
TDFN
Package Code
T1433+2C
Outline Number
21-0137
Land Pattern Number
90-0063
Thermal Resistance, Single-Layer Board:
Junction to Ambient (θJA)
54ºC/W
Junction to Case (θJC)
8ºC/W
Thermal Resistance, Four-Layer Board:
Junction to Ambient (θJA)
41ºC/W
Junction to Case (θJC)
8ºC/W
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board.
For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
www.maximintegrated.com
Maxim Integrated | 6
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Electrical Characteristics
(VBATT = 2.3V to 4.9V, TA = -40ºC to +85ºC, typical value for TA is +25ºC. Limits are 100% tested at TA = +25°C. The operating
temperature range and relevant supply voltage range are guaranteed by design and characterization. Specifications marked "GBD" are
guaranteed by design and not production tested.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
4.9
V
POWER SUPPLY
Supply Voltage
VBATT
(Note 1)
2.3
Shutdown Supply
Current
IDD0
TA ≤ +50ºC
0.5
0.9
μA
Hibernate Supply
Current
IDD1
TA ≤ +50ºC, average current
5.1
12
μA
Active Supply Current
IDD2
TA ≤ +50ºC, average current not including
thermistor measurement current
15
30
μA
Regulation Voltage
VREG
Startup Voltage
1.8
VBATTSU
V
3
V
% of
Reading
ANALOG-TO-DIGITAL CONVERSION
TA = +25ºC
-0.2
+0.2
-40ºC ≤ TA ≤ 85ºC
-0.5
+0.5
CELLX Measurement
Error
VXGERR
CELLX Measurement
Resolution
VXLSB
CELLX Measurement
Range
VXFS
Current Measurement
Offset Error
IOERR
Current Measurement
Error
IGERR
Current Measurement
Resolution
ILSB
1.5625
μV
Current Measurement
Range
IFS
±51.2
mV
Internal Temperature
Measurement Error
TIGERR
±1
ºC
Internal Temperature
Measurement
Resolution
TILSB
0.00391
ºC
78.125
0.92
Long-term average without load current
μV
2
±1.5
-1
-40ºC ≤ TA ≤ +85ºC
V
μV
+1
% of
Reading
INPUT / OUTPUT
External Thermistance
Resistance
REXT10
Config.R100 = 0
10
REXT100
Config.R100 = 1
100
Output Drive Low,
ALRT, SDA
VOL
Input Logic High, ALRT,
SCL, SDA
VIH
Input Logic Low, ALRT,
SCL, SDA
VIL
Battery-Detach
Detection Threshold
www.maximintegrated.com
VDET
IOL = 4mA, VBATT = 2.3V
kΩ
0.4
1.5
Measured as a fraction of VBATT on TH
rising
91
V
V
96.2
0.5
V
99
%
Maxim Integrated | 7
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Electrical Characteristics (continued)
(VBATT = 2.3V to 4.9V, TA = -40ºC to +85ºC, typical value for TA is +25ºC. Limits are 100% tested at TA = +25°C. The operating
temperature range and relevant supply voltage range are guaranteed by design and characterization. Specifications marked "GBD" are
guaranteed by design and not production tested.)
PARAMETER
SYMBOL
Battery-Detach
Detection Threshold
Hysteresis
VDET-HYS
Battery-Detach
Comparator Delay
tTOFF
CONDITIONS
MIN
Measured as a fraction of VBATT on TH
falling
TYP
MAX
1
TH step from 70% to 100% of VBATT
(Alrtp = 0, EnAIN = 1, FTHRM = 1)
UNITS
%
100
μs
+1
μA
RESISTANCE AND LEAKAGE
Leakage Current, CSN,
ALRT
VALRT < 15V
-1
VCELLX < 2.0V
-60
±5
+60
nA
IPD
VSDA = 0.4V, VSCL = 0.4V
0.05
0.2
0.4
μA
SCL Clock Frequency
fSCL
(Note 2)
400
kHz
Bus Free Time Between
a STOP and START
Condition
tBUF
Leakage Current,
CELLX
Input Pulldown Current
ILEAK
ILEAK_CELLX
2-WIRE INTERFACE
Hold Time (Repeated)
START Condition
tHD:STA
(Note 3)
0
1.3
μs
0.6
μs
Low Period of SCL
Clock
tLOW
1.3
μs
High Period of SCL
Clock
tHIGH
0.6
μs
Setup Time for a
Repeated START
Condition
tSU:STA
0.6
μs
Data Hold Time
tHD:DAT
(Notes 4, 5)
Data Setup Time
tSU:DAT
(Note 4)
0
0.9
100
μs
ns
Rise Time of Both SDA
and SCL Signals
tR
5
300
ns
Fall Time of Both SDA
and SCL Signals
tF
5
300
ns
Setup Time for STOP
Condition
tSU:STO
0.6
Spike Pulse Width
Suppressed by Input
Filter
tSP
(Note 6)
50
ns
Capacitive Load for
Each Bus Line
CB
(Note 7)
400
pF
SCL, SDA Input
Capacitance
CBIN
μs
6
pF
TIMING
Time-Base Accuracy
www.maximintegrated.com
tERR
TA = +25°C
-1
+1
%
Maxim Integrated | 8
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Electrical Characteristics (continued)
(VBATT = 2.3V to 4.9V, TA = -40ºC to +85ºC, typical value for TA is +25ºC. Limits are 100% tested at TA = +25°C. The operating
temperature range and relevant supply voltage range are guaranteed by design and characterization. Specifications marked "GBD" are
guaranteed by design and not production tested.)
PARAMETER
TH Precharge Time
SYMBOL
tPRE
CONDITIONS
MIN
8.48
TYP
MAX
UNITS
ms
Note 1: All voltages are referenced to GND.
Note 2: Timing must be fast enough to prevent the IC from entering shutdown mode due to bus low for a period greater than the
shutdown timer setting.
Note 3: fSCL must meet the minimum clock low time plus the rise/fall times.
Note 4: The maximum tHD:DAT has only to be met if the device does not stretch the low period (tLOW) of the SCL signal.
Note 5: This device internally provides a hold time of at least 100ns for the SDA signal (referred to the minimum VIH of the SCL signal)
to bridge the undefined region of the falling edge of SCL.
Note 6: Filters on SDA and SCL suppress noise spikes at the input buffers and delay the sampling instant.
Note 7: CB represents total capacitance of one bus line in pF.
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
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Maxim Integrated | 9
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
www.maximintegrated.com
Maxim Integrated | 10
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Pin Configurations
TDFN
TOP VIEW
(PAD SIDE DOWN)
TH
1
14 SCL
NC
2
13 SDA
SW
3
12 ALRT
NC
4
NC
5
10 CELLX
BATT
6
9
CSPL
CSN
7
8
GND
MAX17261
11 REG
EP
TDFN
WLP
TOP VIEW
(BUMP SIDE DOWN)
MAX17261
TH
SCL
CSN
A1
A2
A3
BATT
ALRT
REG
B1
B2
B3
SDA
CELLX
GND/CSPL
C1
C2
C3
WLP
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Maxim Integrated | 11
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Pin Descriptions
PIN
NAME
FUNCTION
TDFN
WLP
2, 4, 5
—
NC
No Connection.
1
A1
TH
Thermistor Input. Connect a thermistor from TH to GND. TH also provides battery insertion/
removal detection. Connect to BATT if not used.
14
A2
SCL
Serial Clock Input. 2-wire clock line. Input only. SCL has an internal pulldown (IPD) for
sensing disconnection.
13
C1
SDA
Serial Data Input/Output. 2-wire data line. Open-drain output driver. SDA has an internal
pulldown (IPD) for sensing disconnection.
7
A3
CSN
Sense Resistor Negative Sense Point. Kelvin connect to the system side of the sense
resistor.
10
C2
CELLX
Voltage Measurement Point for Multiple-Series Cells Application. Connect to an external
voltage divider circuit to measure a fraction of the cell voltage.
9
—
CSPL
Sense Resistor Positive Sense Point. Kelvin connect to the cell side of the sense resistor.
6
B1
BATT
IC Power Supply. Connect to a 3 to 5 volt supply. Bypass with a 0.1μF capacitor to GND.
—
C3
GND/
CSPL
IC Ground and Sense Resistor Positive Sense Point. Kelvin connect to the cell side of the
sense resistor.
8
—
GND
IC Ground.
11
B3
REG
Internal 1.8V Regulator Output. Bypass with an external 0.47μF capacitor to GND. Do not
load externally.
12
B2
ALRT
Alert Output. The ALRT pin is an open-drain active-low output which indicates fuel-gauge
alerts. Connect to GND if not used.
3
—
SW
www.maximintegrated.com
Gate Switch Signal. Use this pin to control optional FET in resistor divider circuit for low
power operation.
Maxim Integrated | 12
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Functional Diagram
SYSPWR
3~5V
REG
1.8V LDO
BATT
IN
0.1µF
THRM
ENABLE
MUX
SW
CELLX
CSPL (TDFN)
GND
10kΩ/
100kΩ
NTC
www.maximintegrated.com
ALRT
ModelGauge m5
CORE
I2C
INTERFACE
SDA
SCL
INTERNAL
TEMPERATURE
SENSOR
INTERNAL
PULLUP
TH
PROTECTION
CIRCUIT
0.47µF
OUT
32kHz
OSCILLATOR
12-BIT
ADC
REG
MAX17261
EP (TDFN)
RSENSE
CSN
SYSGND
Maxim Integrated | 13
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Detailed Description
The MAX17261 is an ultra-low power fuel gauge IC which implements the Maxim ModelGauge m5 EZ algorithm. The IC
measures voltage, current, and temperature accurately to produce fuel gauge results. The ModelGauge m5 EZ robust
algorithm provides tolerance against battery diversity. This additional robustness enables simpler implementation for
most applications and batteries by avoiding time-consuming battery characterization.
The ModelGauge m5 algorithm combines the short-term accuracy and linearity of a coulomb-counter with the long-term
stability of a voltage-based fuel gauge, along with temperature compensation to provide industry-leading fuel gauge
accuracy. The IC automatically compensates for aging, temperature, and discharge rate and provides accurate state of
charge (SOC) in percentage (%) and remaining capacity in milliampere-hours (mAhr) over a wide range of operating
conditions. Fuel gauge error always converges to 0% as the cell approaches empty.
The IC has a register set that is compatible with Intel's DBPT v2 dynamic power standard. This allows the system
designer to safely estimate the maximum allowed CPU turbo-boost power level in complex power conditions. The IC
provides accurate estimation of time-to-empty and time-to-full and provides three methods for reporting the age of the
battery: reduction in capacity, increase in battery resistance, and cycle odometer.
The IC contains a unique serial number. It can be used for cloud-based authentication. See the Serial Number
Feature section for more information.
Communication to the host occurs over standard I2C interface. For information about I2C communication, refer
to the User Guide 6597: MAX1726x ModelGauge m5 EZ User Guide.
ModelGauge m5 EZ Performance
ModelGauge m5 EZ performance provides plug-and-play operation when the IC is connected to most lithium batteries.
While the IC can be custom tuned to the application's specific battery through a characterization process for ideal
performance, the IC has the ability to provide good performance for most applications with no custom characterization
required. Table 1 and Figure 1 show the performance of the ModelGauge m5 algorithm in applications using ModelGauge
m5 EZ configuration.
The ModelGauge m5 EZ provides good performance for most cell types. For some chemistries, such as lithium-ironphosphate (LiFePO4) and Panasonic NCR/NCA series cells, it is suggested that the customer request a custom model
from Maxim for best performance.
Table 1. ModelGauge m5 EZ Performance
DESCRIPTION
AFTER FIRST CYCLE* (%)
AFTER SECOND CYCLE* (%)
Tests with less than 3% error
95
97
Tests with less than 5% error
98.7
99
Tests with less than 10% error
100
100
*Test conditions: +20°C and +40°C, run time of > 3 hours.
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Maxim Integrated | 14
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
ModelGauge m5 EZ CONFIGURATION PERFORMANCE
60%
PERCENTILE OF TESTS (%)
50%
TEST CONDITIONS:
· 300+ DIFFERENT BATTERIES
· 3000+ DISCHARGES
· BETWEEN +20ºC TO +40ºC
· RUN TIME OF > 3 HOURS
· AFTER FIRST CYCLE
40%
30%
20%
10%
0%
1
2
3
4
5
6
7
8
9
10
WORST CASE ERROR DURING DISCHARGE (%)
Figure 1. ModelGauge m5 EZ Configuration Performance
Application Notes
Refer to the following application notes for additional reference material:
● User Guide 6597: MAX1726x ModelGauge m5 EZ User Guide
• Documents full register set
• More details about ModelGauge m5 algorithm
• Discusses additional applications
● User Guide 6595: MAX1726x Software Implementation Guide
• Guidelines for software drivers including example code
Standard Register Formats
Unless otherwise stated during a given register's description, all IC registers follow the same format depending on the
type of register. See Table 2 for the resolution and range of any register described hereafter. Note that current and
capacity values are displayed as a voltage and must be divided by the sense resistor to determine Amps or Amp-hours.
Table 2. ModelGauge m5 Register Standard Resolutions
REGISTER
TYPE
LSb SIZE
MINIMUM
VALUE
MAXIMUM
VALUE
Capacity
5.0μVh/
RSENSE
0.0μVh
327.675mVh/
RSENSE
www.maximintegrated.com
NOTES
Equivalent to 0.5mAh with a 0.010Ω sense resistor.
Maxim Integrated | 15
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Table 2. ModelGauge m5 Register Standard Resolutions (continued)
REGISTER
TYPE
LSb SIZE
MINIMUM
VALUE
MAXIMUM
VALUE
Percentage
1/256%
0.0%
255.9961%
Voltage
78.125μV
0.0V
5.11992V
Current
1.5625μV/
RSENSE
-51.2mV/
RSENSE
51.1984mV/
RSENSE
Signed 2's complement format. Equivalent to 156.25μA with a
0.010Ω sense resistor.
Temperature
1/256°C
-128.0°C
127.996°C
Signed 2's complement format. 1°C LSb when reading only the
upper byte.
Resistance
1/4096Ω
0.0Ω
15.99976Ω
Time
5.625s
0.0s
102.3984h
Special
NOTES
1% LSb when reading only the upper byte.
On per-cell basis.
Format details are included with the register description.
ModelGauge m5 EZ Configuration Registers
The following registers are inputs to the ModelGauge m5 algorithm and store characterization information for the
application cells as well as important application specific parameters. They are described briefly here.
Only the following information is required for configuring ModelGauge m5 EZ:
● Label Capacity—DesignCap
● Empty Voltage—VEmpty
● Charge Termination Current—ICHGTerm
Refer to the MAX1726x Software Implementation Guide for more details on how to initialize the fuel gauge.
DesignCap Register (18h)
Register Type: Capacity
Initial value: 0x0BB8
The DesignCap register holds the nominal capacity of the cell.
VEmpty Register (3Ah)
Register Type: Special
Initial Value: 0xA561 (3.3V/3.88V)
The VEmpty register sets thresholds related to empty detection during operation. Table 3 shows the register format.
Table 3. VEmpty (3Ah) Format
D15
D14
D13
D12
D11
VE
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
VR
VE: Empty voltage target, during load. The fuel gauge provides capacity and percentage relative to the empty voltage
target, eventually declaring 0% at VE. A 10mV resolution gives a 0V to 5.11V range. This value defaults to 3.3V after
reset.
VR: Recovery voltage. Sets the voltage level for clearing empty detection. Once the cell voltage rises above this point,
empty voltage detection is reenabled. A 40mV resolution gives a 0V to 5.08V range. This value defaults to 3.88V, which
is recommended for most applications.
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Maxim Integrated | 16
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
ModelCfg Register (DBh)
Register Type: Special
The ModelCFG register controls basic options of the EZ algorithm. Table 4 shows the register format.
Table 4. ModelCFG (DBh) Format
D15
Refresh
D14
D13
D12
D11
D10
D9
D8
0
R100
0
0
VChg
0
0
D7
D6
D5
D4
ModelID
D3
D2
D1
D0
1
0
0
0
Refresh: Set Refresh to 1 to command the model reload. After completion the MAX17261 clears Refresh to 0.
R100: if using 100kΩ NTC, set R100 = 1; if using 10kΩ NTC, set R100 = 0.
0: Bit must be written 0. Do not write 1.
1: Bit must be written 1. Do not write 0.
ModelID: Choose from one of the following Lithium models. For the majority of batteries, use ModelID = 0.
ModelID = 0: Use for most lithium cobalt-oxide variants (a large majority of lithium in the market-place). Supported by EZ
without characterization.
ModelID = 2: Use for lithium NCR or NCA cells such as Panasonic. Custom characterization is recommended in this
case.
ModelID = 6: Use for lithium iron-phosphate (LiFePO4). Custom characterization is recommended in this case.
VChg: Set VChg to 1 for charge voltage higher than 4.25V (4.3V–4.4V). Set VChg to 0 for 4.2V charge voltage.
IChgTerm Register (1Eh)
Register Type: Current
Initial Value: 0x0640 (250mA on 10mΩ)
The IChgTerm register allows the device to detect when charge termination has occurred. Program IChgTerm to the
exact charge termination current used in the application.
Refer to the End-of-Charge Detection section of the User Guide 6597: MAX1726x ModelGauge m5 EZ User Guide for
more details.
Config Register (1Dh) and Config2 Register (BBh)
Register Type: Special
Initial Value: 0x2210 for Config, 0x3658 for Config2
The Config registers hold all shutdown enable, alert enable, and temperature enable control bits. Writing a bit location
enables the corresponding function within one task period. Table 5 and Table 6 show the register formats.
Table 5. Config (1Dh) Format
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
TSel
SS
TS
VS
IS
THSH
Ten
Tex
SHDN
COMMSH
0
ETHRM
FTHRM
Aen
Bei
Ber
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Maxim Integrated | 17
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Table 6. Config2 (BBh) Format
D15
D14
D13
D12
0
0
AtRateEn
DPEn
D11
D10
D9
POWR
D8
D7
D6
D5
D4
dSOCen
TAlrtEn
LDMdl
1
D3
D2
DRCfg
D1
D0
CPMode
0
0: Bit must be written 0. Do not write 1.
1: Bit must be written 1. Do not write 0.
TSEL: Temperature sensor select. Set to 0 to use internal die temperature. Set to 1 to use temperature information from
thermistor. ETHRM bit must be set to 1 when TSel is 1.
SS: SOC ALRT Sticky. When SS = 1, SOC alerts can only be cleared through software. When SS = 0, SOC alerts are
cleared automatically when the threshold is no longer exceeded.
TS: Temperature ALRT Sticky. When TS = 1, temperature alerts can only be cleared through software. When TS = 0,
temperature alerts are cleared automatically when the threshold is no longer exceeded.
VS: Voltage ALRT Sticky. When VS = 1, voltage alerts can only be cleared through software. When VS = 0, voltage alerts
are cleared automatically when the threshold is no longer exceeded.
IS: Current ALRT Sticky. When IS = 1, current alerts can only be cleared through software. When IS = 0, current alerts
are cleared automatically when the threshold is no longer exceeded.
THSH: TH Pin Shutdown. Set to 1 to enable device shutdown when the IC is mounted host-side and the battery is
removed. The IC enters shutdown if the TH pin remains high (VTH > VBATT - VDET) for longer than the timeout of the
ShdnTimer register. This also configures the device to wake up when TH is pulled low with a thermistor on-cell insertion.
Note that if COMMSH and AINSH are both set to 0, the device wakes up on any edge of SDA.
Ten: Enable Temperature Channel. Set to 1 and set ETHRM or FTHRM to 1 to enable temperature measurement.
Tex: Temperature External. When set to 1, the fuel gauge requires external temperature measurements to be written
from the host. When set to 0, the ICs own measurements are used instead.
SHDN: Shutdown. Write this bit to logic 1 to force a shutdown of the device after timeout of the ShdnTimer register
(default 45s delay). SHDN is reset to 0 at power-up and upon exiting shutdown mode. In order to command shutdown
within 45 seconds, first write HibCFG = 0x0000 to enter active mode.
COMMSH: Communication Shutdown. Set to logic 1 to force the device to enter shutdown mode if both SDA and SCL
are held low for more than timeout of the ShdnTimer register. This also configures the device to wake up on a rising edge
of any communication. Note that if COMMSH and THSH are both set to 0, the device wakes up on any edge of SDA.
Refer to the User Guide 6597: MAX1726x ModelGauge m5 EZ User Guide for details.
ETHRM: Enable Thermistor. Set to logic 1 to enable the TH pin measurement.
FTHRM: Force Thermistor Bias Switch. This allows the host to control the bias of the thermistor switch or enable
fast detection of battery removal. Set FTHRM = 1 to always enable the thermistor bias switch. With a standard 10kΩ
thermistor, this adds an additional ~200μA to the current drain of the circuit.
Aen: Enable alert on fuel-gauge outputs. When Aen = 1, any violation of the alert threshold register values by
temperature, voltage, current, or SOC triggers an alert. This bit affects the ALRT pin operation only. The Smx, Smn, Tmx,
Tmn, Vmx, Vmn, Imx, and Imn bits of the Status register (000h) are not disabled.
Bei: Enable alert on battery insertion when the IC is mounted host-side. When Bei = 1, a battery-insertion condition, as
detected by the TH pin voltage, triggers an alert.
Ber: Enable alert on battery removal when the IC is mounted host-side. When Ber = 1, a battery-removal condition, as
detected by the TH pin voltage, triggers an alert.
AtRateEn: AtRate enable. When this bit is set to 0, AtRate calculations are disabled and registers AtQResidual/AtTTE/
AtAvSOC/AtAvCap can be used as general purpose memory.
DPEn: Dynamic power enable. When this bit is set to 0, Dynamic Power calculations are disabled and registers
MaxPeakPower/SusPeakPower/MPPCurrent/SPPCurrent can be used as general purpose memory.
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Maxim Integrated | 18
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
POWR: Sets the time constant for the AvgPower register. The default POR value of 0100b gives a time constant of
11.25s. The equation setting the period is:
AvgPower time constant = 45s x 2(POWR-6)
dSOCen: SOC Change Alert Enable. Set this bit to 1 to enable alert output with the Status.dSOCi bit function. Write this
bit to 0 to disable alert output with the Status. dSOCi bit. This bit is set to 0 at power-up.
TAlrten: Temperature Alert Enable. Set this bit to 1 to enable temperature based alerts. Write this bit to 0 to disable
temperature alerts. This bit is set to 1 at power-up.
LDMdl: Host sets this bit to 1 in order to initiate firmware to finish processing a newly loaded model. Firmware clears this
bit to zero to indicate that model loading is finished.
DRCfg: Deep relax time configuration. 00 for 0.8 to 1.6 hours, 01 for 1.6 to 3.2 hours, 10 for 3.2 to 6.4 hours and 11 for
6.4 to 12.8 hours.
CPMode: Constant-power mode. Set to 1 to enable constant-power mode. If it is set to 0, AtRate/AvgCurrent is used for
AvgVCell
(At)TTE/(At)QResidual/(At)AvSOC/(At)AvCap. If it is set to 1, AtRate/AvgCurrent x (AvgVCell + VEmpty) 2 is used for those
/
calculations
ModelGauge m5 EZ Algorithm
Classical coulomb-counter-based fuel gauges have excellent linearity and short-term performance. However, they suffer
from drift due to the accumulation of the offset error in the current-sense measurement. Although the offset error is often
very small, it cannot be eliminated. It causes the reported capacity error to increase over time and requires periodic
corrections. Corrections are traditionally performed at full or empty. Some other systems also use the relaxed battery
voltage to perform corrections. These systems determine the true state-of-charge (SOC) based on the battery voltage
after a long time of no current flow. Both have the same limitation: if the correction condition is not observed over time in
the actual application, the error in the system is boundless. The performance of classic coulomb counters is dominated by
the accuracy of such corrections. Voltage measurement based SOC estimation has accuracy limitations due to imperfect
cell modeling, but does not accumulate offset error over time.
The IC includes an advanced voltage fuel gauge (VFG) that estimates open-circuit voltage (OCV), even during current
flow, and simulates the nonlinear internal dynamics of a Li+ battery to determine the SOC with improved accuracy. The
model considers the time effects of a battery caused by the chemical reactions and impedance in the battery to determine
SOC. This SOC estimation does not accumulate offset error over time. The IC performs a smart empty compensation
algorithm that automatically compensates for the effect of temperature condition and load condition to provide accurate
state-of-charge information. The converge-to-empty function eliminates error toward empty state. The IC learns battery
capacity over time automatically to improve long-term performance. The age information of the battery is available in the
output registers.
The ModelGauge m5 algorithm combines a high-accuracy coulomb counter with a VFG. See Figure 2. The
complementary combined result eliminates the weaknesses of both the coulomb counter and the VFG while providing
the strengths of both. A mixing algorithm weighs and combines the VFG capacity with the coulomb counter and weighs
each result so that both are used optimally to determine the battery state. In this way, the VFG capacity result is used to
continuously make small adjustments to the battery state, cancelling the coulomb-counter drift.
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Maxim Integrated | 19
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
RSENSE
CURRENT
INTEGRATOR
ModelGauge
ALGORITHM
COULOMB
COUNTER
Q CHANGE
%SOC CHANGE
CAPACITY
MICROCORRECTIONS
FULL, EMPTY, AND
STANDBY-STATE
DETECTION UNNECESSARY
Figure 2. ModelGauge m5 EZ Algorithm
The ModelGauge m5 algorithm uses this battery state information and accounts for temperature, battery current, age,
and application parameters to determine the remaining capacity available to the system. As the battery approaches the
critical region near empty, the ModelGauge m5 algorithm invokes a special error correction mechanism that eliminates
any error.
The ModelGauge m5 algorithm continually adapts to the cell and application through independent learning routines. As
the cell ages, its change in capacity is monitored and updated and the voltage-fuel-gauge dynamics adapt based on cellvoltage behavior in the application.
For even better fuel-gauging accuracy than ModelGauge m5 EZ, contact Maxim for information regarding cell
characterization.
ModelGauge m5 Algorithm Output Registers
The following registers are outputs from the ModelGauge m5 algorithm. The values in these registers become valid
351ms after the IC is configured.
RepCap Register (05h)
Register Type: Capacity
RepCap or reported remaining capacity in mAh. The ModelGauge m5 algorithm prevents remaining capacity from making
a sudden jump during load change conditions.
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Maxim Integrated | 20
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
RepSOC Register (06h)
Register Type: Percentage
RepSOC is the reported state-of-charge percentage output for use by the application GUI.
FullCapRep Register (10h)
Register Type: Capacity
This register reports the full capacity that goes with RepCap, generally used for reporting to the user. A new full-capacity
value is calculated at the end of every charge cycle in the application.
TTE Register (11h)
Register Type: Time
The TTE register holds the estimated time to empty for the application under present temperature and load conditions.
TTE register is only valid when current register is negative.
TTF Register (20h)
Register Type: Time
The TTF register holds the estimated time to full for the application under present conditions. The TTF value is
determined by learning the constant current and constant voltage portions of the charge cycle based on experience of
prior charge cycles. Time-to-full is then estimated by comparing the present charge current to the charge termination
current. Operation of the TTF register assumes all charge profiles are consistent in the application. The TTF register is
only valid when the current register is positive.
Cycles Register (17h)
Register Type: Special
The Cycles register maintains a total count of the number of charge/discharge cycles of the cell. The result is stored
as a fraction of a full cycle. For example, a full charge/discharge cycle results in the Cycles register incrementing by
100%. The Cycles register accumulates fractional or whole cycles. For example, if a battery is cycled 10% x 10 times,
then it is equivalent to 100% of one cycle. The Cycles register has a full range of 0 to 655.35 cycles with a 1% LSb.
Status Register (00h)
Register Type: Special
Initial Value: 0x8082
The Status register maintains all flags related to alert thresholds and battery insertion or removal. Table 7 shows the
Status register format.
Table 7. Status (00h) Format
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Br
Smx
Tmx
Vmx
Bi
Smn
Tmn
Vmn
dSOCi
Imx
X
X
Bst
Imn
POR
X
POR (Power-On Reset): This bit is set to 1 when the device detects that a software or hardware POR event has
occurred. This bit must be cleared by system software to detect the next POR event. POR is set to 1 at power-up.
Imn and Imx (Minimum/Maximum Current-Alert Threshold Exceeded): These bits are set to 1 whenever a Current
register reading is below (Imn) or above (Imx) the IAlrtTh thresholds. These bits may or may not need to be cleared by
system software to detect the next event. See Config.IS bit description. Imn and Imx are cleared to 0 at power-up.
Vmn and Vmx (Minimum/Maximum Voltage-Alert Threshold Exceeded): These bits are set to 1 whenever a VCell
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Maxim Integrated | 21
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
register reading is below (Vmn) or above (Vmx) the VAlrtTh thresholds. These bits may or may not need to be cleared by
system software to detect the next event. See Config.VS bit description. Vmn and Vmx are cleared to 0 at power-up.
Tmn and Tmx (Minimum/Maximum Temperature-Alert Threshold Exceeded): These bits are set to 1 whenever a
Temperature register reading is below (Tmn) or above (Tmx) the TAlrtTh thresholds. These bits may or may not need to
be cleared by system software to detect the next event. See Config.TS bit description. Tmn and Tmx are cleared to 0 at
power-up.
Smn and Smx (Minimum/Maximum SOC-Alert Threshold Exceeded): These bits are set to 1 whenever SOC is below
(Smn) or above (Smx) the SAlrtTh thresholds. These bits may or may not need to be cleared by system software to
detect the next event. See Config.SS description. Smn and Smx are cleared to 0 at power-up.
Bst (Battery Status): Useful when the IC is used in a host-side application. This bit is set to 0 when a battery is present
in the system, and set to 1 when the battery is absent. Bst is set to 0 at power-up.
dSOCi (State-of-Charge 1% Change Alert): This is set to 1 whenever the RepSOC register crosses an integer
percentage boundary such as 50.0%, 51.0%, etc. Must be cleared by host software. dSOCi is set to 1 at power-up.
Bi (Battery Insertion): Useful when the IC is used in a host-side application. This bit is set to 1 when the device detects
that a battery has been inserted into the system by monitoring the TH pin. This bit must be cleared by system software
to detect the next insertion event. Bi is set to 0 at power-up.
Br (Battery Removal): Useful when the IC is used in a host-side application. This bit is set to 1 when the system detects
that a battery has been removed from the system. This bit must be cleared by system software to detect the next removal
event. Br is set to 1 at power-up.
X (Don’t Care): This bit is undefined and can be logic 0 or 1.
Analog Measurements
The IC monitors voltage, current, and temperature. This information is provided to the fuel guage algorithm to predict cell
capacity and also made available to the user.
Voltage Measurement
VCell Register (09h)
Register Type: Voltage
VCell register reports the 2.5X the voltage measured at the CELLX pin. This represents the voltage per cell of the battery
pack.
AvgVCell Register (19h)
Register Type: Voltage
The AvgVCell register reports an average of the VCell register readings.
MaxMinVolt Register (1Bh)
Register Type: Special
Initial Value: 0x00FF
The MaxMinVolt register maintains the maximum and minimum of VCell register values since device reset. At power-up,
the maximum voltage value is set to 00h (the minimum) and the minimum voltage value is set to FFh (the maximum).
Therefore, both values are changed to the voltage register reading after the first update. Host software can reset this
register by writing it to its power-up value of 0x00FF. The maximum and minimum voltages are each stored as 8-bit
values with a 20mV resolution. Table 8 shows the register format.
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Maxim Integrated | 22
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Table 8. MaxMinVolt (1Bh) Format
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
MaxVCELL
D4
D3
D2
D1
D0
MinVCELL
MaxVCELL: Maximum VCell register reading
MinVCELL: Minimum VCell register reading
Current Measurement
The IC monitors the current flow through the battery by measuring the voltage across the current-sensing element over
a ±51.2mV range. The IC is precalibrated for current-measurement accuracy in Maxim's factory.
Additionally, the IC maintains a record of the minimum and maximum current measured by the IC and an average current.
See the Layout Guidelines section for the recommended board layout to minimize current-sense error.
Current Register (0Ah)
Register Type: Current
The IC measures the voltage across the sense resistor, and the result is stored as a two’s complement value in the
Current register. Voltages outside the minimum and maximum register values are reported as the minimum or maximum
value. The register value should be divided by the sense resistance to convert to amperes. The value of the sense resistor
determines the resolution and the full-scale range of the current readings. Table 9 shows range and resolution values
for typical sense resistances. This is for rechargeable applications. Non-rechargeable applications with long run-times
should generally use higher sense resistor value.
Table 9. Current Measurement Range and Resolution vs. Sense Resistor Value
BATTERY FULL
CAPACITY (mAh)
SENSE
RESISTOR (mΩ)
CURRENT REGISTER
RESOLUTION (μA)
CURRENT REGISTER
RANGE (A)
CAPACITY
RESOLUTION (mAh)
> 4000
1
1562.5
± 51.2
5
> 2000
2
781.25
± 25.6
2.5
> 800
5
312.5
± 10.24
1
> 400
10
156.25
± 5.12
0.5
> 200
20
78.125
± 2.56
0.25
> 80
50
31.25
± 1.024
0.1
AvgCurrent Register (0Bh)
Register Type: Current
The AvgCurrent register reports an average of Current register readings.
MaxMinCurr Register (1Ch)
Register Type: Special
Initial Value: 0x807F
The MaxMinCurr register maintains the maximum and minimum Current register values since the last IC reset or until
cleared by host software. At power-up, the maximum current value is set to 80h (most negative) and the minimum current
value is set to 7Fh (most positive). Therefore, both values are changed to the Current register reading after the first
update. Host software can reset this register by writing it to its power-up value of 0x807F. The maximum and minimum
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Maxim Integrated | 23
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
currents are each stored as two’s complement 8-bit values with (0.4mV) / Rsense resolution. Table 10 shows the register
format.
Table 10. MaxMinCurr (1Ch) Format
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
MaxCurrent
D4
D3
D2
D1
D0
MinCurrent
MaxCurrent: Maximum Current register reading
MinCurrent: Minimum Current register reading
Temperature Measurement
The IC can be configured to measure its own internal die temperature or an external NTC thermistor.
Set Config.TSEL = 0 (default) to enable die temperature measurement. Set Config.TSEL = 1 to enable thermistor
measurement.
Thermistor conversions are initiated by periodically connecting the TH and BATT pins internally. Measurement results of
TH pin are compared to the voltage of the BATT pin and converted to a ratiometric value from 0% to 100%. The active
pullup is disabled when temperature measurements are complete. This reduces the current consumption.
The ratiometric results are converted to temperature using the temperature gain (TGain), temperature offset (TOff), and
temperature curve (Curve) register values. Internal die temperature measurements are factory calibrated and are not
affected by TGain, TOff, and Curve register settings. Refer to the User Guide 6597: MAX1726x ModelGauge m5 EZ
User Guide for more details. Additionally, the IC maintains a record of the minimum and maximum temperature measured
and an average temperature.
Temp Register (08h)
Register Type: Temperature
The Temp register provides the temperature measured by the thermistor or die temperature based on the Config register
setting.
AvgTA Register (16h)
Register Type: Temperature
The AvgTA register reports an average of the readings from the Temp register.
MaxMinTemp Register (1Ah)
Register Type: Special
Initial Value: 0x807F
The MaxMinTemp register maintains the maximum and minimum Temp register (08h) values since the last fuel-gauge
reset or until cleared by host software. At power-up, the maximum value is set to 0x80 (most negative) and the minimum
value is set to 0x7F (most positive). Therefore, both values are changed to the Temp register reading after the first
update. Host software can reset this register by writing it to its power-up value of 0x807F. The maximum and minimum
temperatures are each stored as two’s complement 8-bit values with 1°C resolution. Table 11 shows the format of the
register.
Table 11. MaxMinTemp (1Ah) Format
D15
D14
D13
D12
D11
MaxTemperature
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D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
MinTemperature
Maxim Integrated | 24
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
MaxTemperature: Maximum Temp register reading
MinTemperature: Minimum Temp register reading
DieTemp Register (034h)
Register Type: Temperature
The DieTemp register provides the internal die temperature measurement. If Config.TSel = 0, DieTemp and Temp
registers have the value of the die temperature.
Power Register (B1h)
Instant power calculation from immediate current and voltage. The LSB is (8μV2) / Rsense.
AvgPower Register (B3h)
Filtered average power from the Power register. The LSB is (8μV2) / Rsense.
Alert Function
The Alert Threshold registers allow interrupts to be generated by detecting a high or low voltage, current, temperature,
or state-of-charge. Interrupts are generated on the ALRT pin open-drain output driver. An external pullup is required to
generate a logic-high signal. Alerts can be triggered by any of the following conditions:
• Battery removal: (VAIN > VTHRM – VDET) and battery removal detection enabled (Ber = 1).
• Battery insertion: (VAIN < VTHRM – VDET-HYS) and battery insertion detection enabled (Bei = 1).
• Over/undervoltage: VAlrtTr register threshold violation (upper or lower) and alerts enabled (Aen = 1).
• Over/undertemperature: TAlrtTr register threshold violation (upper or lower) and alerts enabled (Aen = 1).
• Over/undercurrent: IAlrtTr register threshold violation (upper or lower) and alerts enabled (Aen = 1).
• Over/under SOC: SAlrtTr register threshold violation (upper or lower) and alerts enabled (Aen = 1).
• 1% SOC change: RepSOC register bit d8 (1% bit) changed (dSOCen = 1).
To prevent false interrupts, the threshold registers should be initialized before setting the Aen bit. Alerts generated
by battery insertion or removal can only be reset by clearing the corresponding bit in the Status (00h) register. Alerts
generated by a threshold-level violation can be configured to be cleared only by software, or cleared automatically when
the threshold level is no longer violated. See the Config (1Dh) and Config2 (BBh) register descriptions for details of the
alert function configuration.
VAlrtTh Register (01h)
Register Type: Special
Initial Value: 0xFF00 (Disabled)
The VAlrtTh register shown in Table 12 sets upper and lower limits that generate an alert if exceeded by the VCell register
value. The upper 8 bits set the maximum value and the lower 8 bits set the minimum value. Interrupt threshold limits are
selectable with 20mV resolution over the full operating range of the VCell register.
Table 12. VAlrtTh (01h) Format
D15
D14
D13
D12
VMAX
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
VMIN
VMAX: Maximum voltage reading. An alert is generated if the VCell register reading exceeds this value.
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Maxim Integrated | 25
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
VMIN: Minimum voltage reading. An alert is generated if the VCell register reading falls below this value.
TAlrtTh Register (02h)
Register Type: Special
Initial Value: 0x7F80 (Disabled)
The TAlrtTh register (Table 13) sets upper and lower limits that generate an alert if exceeded by the Temp register value.
The upper 8 bits set the maximum value and the lower 8 bits set the minimum value. Interrupt threshold limits are stored
in 2’s-complement format with 1°C resolution over the full operating range of the Temp register.
Table 13. TAlrtTh (02h) Format
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
TMAX
D4
D3
D2
D1
D0
TMIN
TMAX: Maximum temperature reading. An alert is generated if the Temp register reading exceeds this value.
TMIN: Minimum temperature reading. An alert is generated if the Temp register reading falls below this value.
SAlrtTh Register (03h)
Register Type: Special
Initial Value: 0xFF00 (Disabled)
The SAlrtTh register shown (Table 14) sets upper and lower limits that generate an alert if exceeded by RepSOC. The
upper 8 bits set the maximum value and the lower 8 bits set the minimum value. Interrupt threshold limits are configurable
with 1% resolution over the full operating range of the RepSOC register.
Table 14. SAlrtTh (03h) Format
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
SMAX
D4
D3
D2
D1
D0
SMIN
SMAX: Maximum state-of-charge threshold. An alert is generated if the RepSOC register exceeds this value.
SMIN: Minimum state-of-charge threshold. An alert is generated if the RepSOC register falls below this value.
IAlrtTh Register (B4h)
Register Type: Special
Initial Value: 0x7F80 (Disabled)
The IAlrtTh register (Table 15) sets upper and lower limits that generate an alert if exceeded by the Current register
value. The upper 8 bits set the maximum value and the lower 8 bits set the minimum value. Interrupt threshold limits are
selectable with 0.4mV/RSENSE resolution over the full operating range of the Current register.
Table 15. IAlrtTh (B4h) Format
D15
D14
D13
D12
IMAX
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
IMIN
IMAX: Maximum current reading. An alert is generated if the current register reading exceeds this value.
IMIN: Maximum current reading. An alert is generated if the current register reading falls below this value.
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Maxim Integrated | 26
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Serial Number Feature
Each IC provides a unique serial number ID. To read this serial number, clear the AtRateEn and the DPEn
bit in the Config2 register. The 128-bit serial information overwrites the Dynamic Power and AtRate output
registers. To continue Dynamic Power and AtRate operations after reading the serial number, the host should set
Config2.AtRateEn and Config2.DPEn to 1.
Table 16. Serial Number Format
ADDRESS
Config2.AtRateEn = 1 || Config2.DPEn = 1
Config2.AtRateEn = 0 && Config2.DPEn = 0
0xD4
MaxPeakPower
Serial Number Word0
0xD5
SusPeakPower
Serial Number Word1
0xD9
MPPCurrent
Serial Number Word2
0xDA
SPPCurrent
Serial Number Word3
0xDC
AtQResidual
Serial Number Word4
0xDD
AtTTE
Serial Number Word5
0xDE
AtAvSoc
Serial Number Word6
0xDF
AtAvCap
Serial Number Word7
ModelGauge m5 Memory Space
Registers that relate to functionality of the ModelGauge m5 fuel gauge are located on pages 0h-4h and are
continued on pages Bh and Dh. See the ModelGauge m5 EZ Algorithm section for details of specific register
operation. Register locations marked reserved should not be written to.
Table 17. ModelGauge m5 Register Memory Map
PAGE/
WORD
00h
10h
20h
30h
40h
B0h
D0h
0h
Status
FullCapRep
TTF
Reserved
Reserved
Status2
RSense /
UserMem3
1h
VAlrtTh
TTE
DevName
Reserved
Reserved
Power
ScOcvLim
2h
TAlrtTh
QRTable00
QRTable10
ID /
UserMem2
VGain
3h
SAlrtTh
FullSocThr
FullCapNom
Reserved
RGain
AvgPower
SOCHold
4h
AtRate
RCell
Reserved
DieTemp
Reserved
IAlrtTh
MaxPeakPower
5h
RepCap
Reserved
Reserved
FullCap
dQAcc
TTFCfg
SusPeakPower
6h
RepSOC
AvgTA
Reserved
Reserved
dPAcc
CVMixCap
PackResistance
7h
Age
Cycles
AIN
Reserved
Reserved
CVHalfTime
SysResistance
8h
Temp
DesignCap
LearnCfg
RComp0
Reserved
CGTempCo
MinSysVoltage
9h
VCell
AvgVCell
FilterCfg
TempCo
ConvgCfg
Curve
MPPCurrent
Ah
Current
MaxMinTemp
RelaxCfg
VEmpty
VFRemCap
HibCfg
SPPCurrent
Bh
AvgCurrent
MaxMinVolt
MiscCfg
Reserved
Reserved
Config2
ModelCfg
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QRTable20 QRTable30
Maxim Integrated | 27
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Table 17. ModelGauge m5 Register Memory Map (continued)
PAGE/
WORD
00h
10h
20h
30h
40h
B0h
D0h
Ch
QResidual
MaxMinCurr
TGain
Reserved
Reserved
VRipple
AtQResidual
Dh
MixSOC
Config
TOff
FStat
QH
RippleCfg
AtTTE
Eh
AvSOC
IChgTerm
CGain
Timer
Reserved
TimerH
AtAvSOC
Fh
MixCap
AvCap
COff
ShdnTimer
Reserved
Reserved
AtAvCap
Layout Guidelines
Proper circuit layout as shown in Figure 3 is essential for voltage, temperature, and current-measurement accuracy. The
recommended layout guidelines are as follows:
● CSN and GND traces should make Kelvin connections to the sense resistor. Current is measured differentially through
the CSN and GND pins. Any shared high current paths on these traces affect current-measurement accuracy.
● For TDFN package designs, connect EP directly to the GND pin.
● REG capacitor trace loop area should be minimized. REG should be connected to the GND pin as close as possible
to the IC. Run only a single GND trace to the sense resistor. This helps filter any noise from the internal regulated
supply.
● All other ground connections should be kept separate from the current sensing traces.
• The Kelvin lines should not be shared with other circuits.
• Vias on the Kelvin traces are not recommended.
● There are no limitations on any other IC connection. Other IC pins, as well as any external components mounted to
these pins, have no special layout requirements.
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Maxim Integrated | 28
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
SYSPWR
Pack +
1
14
SCL
NC
2
13
SDA
SW
3
12
ALRT
NC
4
11
REG
NC
5
10
CELLX
BATT
6
9
CSPL
CSN
7
8
GND
CBATT
REG_3V3
TH
MAX17261
CREG
EP
SYSGND
Rsense
Pack -
Pack +
SYSPWR
REG_3V3
CBATT
SDA
BATT
TH
CELLX
ALRT
SCL
GND
REG
CSN
MAX17261
CREG
Pack -
Rsense
SYSGND
Figure 3. MAX17261 Layout Guide
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Maxim Integrated | 29
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Typical Application Circuits
Figure 4 shows a typical operating circuit for low-side current sensing. A sense resistor is typically used. Alternatively, a PCB trace
can be used for high-current or small-form-factor applications. For better measurement, place the sensing element as close as
possible to the CSN and GND pin. The IC automatically compensates for the effect of environmental temperature and trace heating
on trace resistance.
Figure 5 shows a typical application circuit for multiple-series cells. An external 3V to 5V regulator is required to provide regulated
output within BATT pin supply range. Multiple-series-cells measurement requires external voltage divider circuit. The resistor divider
should be configured so that 40% of one-cell voltage is measured at analog measurement pin CELLX. As it is configured in Figure 5,
the resistor divider ratio is R2/R1 = 5/2 x (N-1) + 3/2, where R2 is the resistance between CELLX pin and the battery pack positive
terminal, R1 is the resistance between the CELLX pin and the GND pin, and N is the number of cells. For additional power savings, in
trade-off with BOM cost, add a N-channel MOSFET as shown in Figure 5. The gate of the FET is controlled by the SW pin. The SW
pin only turns on the resistor divider for a short period of time every time ADC measurement occurs. Higher resistance value for the
divider circuit degrades the accuracy of analog measurement, while lower resistance causes more power consumption. The
suggested R1 value is 200kΩ. Typical consumption without NMOS is 8μA. For the accuracy of the voltage measurement, use 0.1%
resistors.
PACK+
SYSPWR
SYSPWR
3~5V
REG
3~5V
REG
BATT
BATT
0.1µF
0.1µF
REG
REG
0.47µF
CELLX
0.47µF
CELLX
PROTECTION
CIRCUIT
ALRT
ALRT
SDA
SCL
SDA
SCL
PROTECTION
CIRCUIT
MAX17261
THRM
TH
CSPL (TDFN)
EP (TDFN)
GND
MAX17261
TH
CSPL (TDFN)
EP (TDFN)
GND
CSN
CSN
10kΩ
NTC
BATTERY
PACK-
SYSTEM
10mΩ RSENSE or
2mΩ PCB TRACE
SYSGND
CAPTIVE BATTERY SYSTEM
10mΩ RSENSE or
2mΩ PCB TRACE
SYSGND
Figure 4. Low-Side Current Measurement Typical Applications Circuit
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Maxim Integrated | 30
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Typical Application Circuits (continued)
SYSPWR
500kΩ
N
(N-1)x500kΩ
REG
BATT
5.6V
0.47µF
2.2µF
300kΩ
ALRT
N CELLS
MAX17261
(TDFN Only)
N
SW
1MΩ
SDA
SCL
CELLX
TH
200kΩ
CSPL (TDFN)
EP (TDFN)
GND
CSN
10kΩ
NTC
RSENSE
PROTECTION
CIRCUIT
SYSGND
Figure 5. Multiple-Series Battery Typical Applications Circuit
Ordering Information
PART NUMBER
TEMP. RANGE
DESCRIPTION
PIN-PACKAGE
MAX17261MEWL+
-40°C to +85°C
Multi-Cell Fuel Gauge with ModelGauge m5 EZ
9-WLP
MAX17261MEWL+T
-40°C to +85°C
Multi-Cell Fuel Gauge with ModelGauge m5 EZ
9-WLP
MAX17261METD+
-40°C to +85°C
Multi-Cell Fuel Gauge with ModelGauge m5 EZ
14-TDFN-EP*
MAX17261METD+T
-40°C to +85°C
Multi-Cell Fuel Gauge with ModelGauge m5 EZ
14-TDFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape-and-reel.
*EP = Exposed Pad.
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Maxim Integrated | 31
MAX17261
5.1μA Multi-Cell Fuel Gauge
with ModelGauge m5 EZ
Revision History
REVISION
NUMBER
REVISION
DATE
0
5/18
DESCRIPTION
Initial release
PAGES
CHANGED
—
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max
limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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