EVALUATION KIT AVAILABLE
Click here for production status of specific part numbers.
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
General Description
Benefits and Features
The MAX17262 is an ultra-low power fuel-gauge IC which
implements the Maxim ModelGauge™ m5 algorithm. The
IC monitors a single-cell battery pack and supports internal current sensing for up to 3.1A pulse current. The IC
provides best performance for batteries with 100mAhr to
6Ahr capacity.
● 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, Temperature
• Does Not Require Empty, Full, or Idle States
The ModelGauge m5 EZ makes fuel-gauge implementation easy by eliminating battery characterization requirements and simplifying host software interaction. The
ModelGauge m5 EZ robust algorithm provides tolerance
against battery diversity for most lithium batteries and
applications.
The ModelGauge m5 EZ algorithm combines the shortterm 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, and discharge rate,
and provides accurate state-of-charge (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 ModelGauge m5 algorithm invokes a special correction mechanism that eliminates any error. The IC provides accurate estimation of time-to-empty and time-tofull 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 wafer-level
package (WLP).
● Low 5.2μA Operating Current
● Integrated Internal Current Sensing
• 7mΩ Typical, up to 3.1A Pulse Currents
● 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
• Constant Power or Constant Current
● 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
BATT
Wearables and Smartwatches
Bluetooth Headset Cases
Health and Fitness Monitors
Medical Devices
Handheld Computers and Terminals
Home and Building Automation, Sensors
Toys
ModelGauge is a trademark of Maxim Integrated Products, Inc.
19-100308; Rev 0; 7/18
SYSPWR
0.1µF
ALRT
SDA
SCL
PROTECTION
CIRCUIT
TH
Applications
●
●
●
●
●
●
●
SYS
10kΩ
NTC
MAX17262
REG
0.47µF
GND
SYSGND
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
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
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Typical Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Pin Configuration(s). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
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 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
AvgVCell Register (19h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
MaxMinVolt Register (1Bh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Current Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
www.maximintegrated.com
Maxim Integrated | 2
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
TABLE OF CONTENTS (CONTINUED)
Current Register (0Ah). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
AvgCurrent Register (0Bh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
MaxMinCurr Register (1Ch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Temperature Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Temp Register (08h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
AvgTA Register (16h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
MaxMinTemp Register (1Ah) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
DieTemp Register (034h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Power Register (B1h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
AvgPower Register (B3h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Alert Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
VAlrtTh Register (01h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
TAlrtTh Register (02h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
SAlrtTh Register (03h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
IAlrtTh Register (B4h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Serial Number Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
ModelGauge m5 Memory Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Layout Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
www.maximintegrated.com
Maxim Integrated | 3
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
LIST OF FIGURES
Figure 1. ModelGauge m5 EZ Configuration Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 2. ModelGauge m5 Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 3. Current Limit Based On Utilization Patterns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 4. MAX17262 Layout Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
www.maximintegrated.com
Maxim Integrated | 4
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 7. Status (00h) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 8. MaxMinVolt (1Bh) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 9. MaxMinCurr (1Ch) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 10. MaxMinTemp (1Ah) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 11. VAlrtTh (01h) Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 12. TAlrtTh (02h) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 13. SAlrtTh (03h) Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 14. IAlrtTh (B4h) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 15. Serial Number Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 16. ModelGauge m5 Register Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
www.maximintegrated.com
Maxim Integrated | 5
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
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
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
SYS to GND ............................................................. -0.3V to +6V
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
Current Limit of Sense Resistor (Continuous current at 100%
utilization (Note 1)).................................................................1.7A
Current Limit of Sense Resistor (Continuous current at 10%
utilization (Note 1)).................................................................2.4A
Current Limit of Sense Resistor (Peak pulsed current, 250ms
maximum pulse width, 10% maximum duty cycle, 1% utilization
(Note 1)).................................................................................3.1A
Note 1: Guaranteed by design and not production tested. Total available utilization is 100,000 hours. Utilization is proportionately
cumulative. See the Current Measurement section for a detailed explanation of the current limit under different utilization
patterns.
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
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
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
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 2)
2.3
Shutdown Supply
Current
IDD0
TA ≤ +50ºC
0.5
0.9
μA
Hibernate Supply
Current
IDD1
TA ≤ +50ºC, average current
5.2
12
μA
Active Supply Current
IDD2
TA ≤ +50ºC, average current not including
thermistor measurement current
16
30
μA
Regulation Voltage
VREG
Startup Voltage
1.8
VBATTSU
V
3
V
ANALOG-TO-DIGITAL CONVERSION
BATT Measurement
Error
VGERR
BATT Measurement
Resolution
VLSB
BATT Measurement
Range
VFS
TA = +25ºC
-7.5
+7.5
-40ºC ≤ TA ≤ +85ºC
-20
+20
78.125
2.3
mV
μV
4.9
V
Sense Resistance
RSNS
TA = +25°C
7
mΩ
Current Measurement
Offset Error
IOERR
Zero current, long term average
±1
mA
Current Measurement
Resolution
ILSB
0.15625
mA
Current Measurement
Gain Error
IGERR
±2.5
% of
Reading
Current Measurement
Error
IERR
Internal Temperature
Measurement Error
TIGERR
Internal Temperature
Measurement
Resolution
TILSB
(Note 9)
TA ≤ +50ºC, 0.5A and 1A (Note 9)
-3
-40ºC ≤ TA ≤ +85ºC
+3
% of
Reading
±1
ºC
0.00391
ºC
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
www.maximintegrated.com
IOL = 4mA, VBATT = 2.3V
kΩ
0.4
1.5
V
V
0.5
V
Maxim Integrated | 7
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
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
CONDITIONS
Battery-Detach
Detection Threshold
VDET
Measured as a fraction of VBATT on TH
rising
Battery-Detach
Detection Threshold
Hysteresis
VDET-HYS
Measured as a fraction of VBATT on TH
falling
Battery-Detach
Comparator Delay
tTOFF
TH step from 70% to 100% of VBATT
(Alrtp = 0, EnAIN = 1, FTHRM = 1)
Leakage Current, CSN,
ALRT
ILEAK
VALRT < 15V
Input Pulldown Current
IPD
VSDA = 0.4V, VSCL = 0.4V
SCL Clock Frequency
fSCL
(Note 3)
Bus Free Time Between
a STOP and START
Condition
tBUF
MIN
TYP
MAX
UNITS
91
96.2
99
%
1
%
100
μs
+1
μA
0.4
μA
400
kHz
LEAKAGE
-1
0.05
0.2
2-WIRE INTERFACE
Hold Time (Repeated)
START Condition
tHD:STA
(Note 4)
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
(Note 5, Note 6)
Data Setup Time
tSU:DAT
(Note 5)
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 7)
50
ns
Capacitive Load for
Each Bus Line
CB
(Note 8)
400
pF
SCL, SDA Input
Capacitance
www.maximintegrated.com
CBIN
μs
6
pF
Maxim Integrated | 8
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
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
CONDITIONS
MIN
TYP
MAX
UNITS
+1
%
TIMING
Time-Base Accuracy
tERR
TH Precharge Time
tPRE
TA = +25°C
-1
8.48
ms
Note 2: All voltages are referenced to GND.
Note 3: 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 4: fSCL must meet the minimum clock low time plus the rise/fall times.
Note 5: The maximum tHD:DAT has only to be met if the device does not stretch the low period (tLOW) of the SCL signal.
Note 6: This device internally provides a hold time of at least 100ns for the SDA signal (refer to the minimum VIH of the SCL signal)
to bridge the undefined region of the falling edge of SCL.
Note 7: Filters on SDA and SCL suppress noise spikes at the input buffers and delay the sampling instant.
Note 8: CB represents total capacitance of one bus line in pF.
Note 9: Guaranteed by design and not production tested.
www.maximintegrated.com
Maxim Integrated | 9
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
www.maximintegrated.com
Maxim Integrated | 10
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
www.maximintegrated.com
Maxim Integrated | 11
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Pin Configuration(s)
TOP VIEW
(BUMP SIDE DOWN)
MAX17262
TH
BATT
NC
A1
A2
A3
SCL
ALRT
SYS
B1
B2
B3
SDA
REG
GND
C1
C2
C3
WLP
Pin Descriptions
PIN
NAME
A3
NC
No Connection.
A1
TH
Thermistor Input. Connect a thermistor from TH to GND. TH also provides battery insertion/removal
detection. Connect to BATT if not used.
B1
SCL
Serial Clock Input. 2-wire clock line. Input only. SCL has an internal pulldown (IPD) for sensing
disconnection.
C1
SDA
Serial Data Input/Output. 2-wire data line. Open-drain output driver. SDA has an internal pulldown (IPD)
for sensing disconnection.
B3
SYS
System Power. Connect to system load.
A2
BATT
IC Power Supply and Battery Voltage Sense Input. Connect to the positive terminal of a battery
cell. Bypass with a 0.1μF capacitor to GND.
C3
GND
IC Ground.
C2
REG
Internal 1.8V Regulator Output. Bypass with an external 0.47μF capacitor to GND. Do not load
externally.
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.
www.maximintegrated.com
FUNCTION
Maxim Integrated | 12
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Functional Diagram
SYS
BATT
SYSPWR
0.1µF
THRM
ENABLE
TH
INTERNAL
PULLUP
INTERNAL
TEMPERATURE
SENSOR
ALRT
ModelGauge m5
CORE
MUX
PROTECTION
CIRCUIT
10kΩ/
100kΩ
NTC
32kHz
OSCILLATOR
ADC
MAX17262
BATT
I2C
INTERFACE
SDA
SCL
1.8V LDO
REG
IN
OUT
0.47µF
GND
SYSGND
www.maximintegrated.com
Maxim Integrated | 13
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Detailed Description
The MAX17262 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 IC features internal current
measurement for up to 3.1A pulse currents. The IC provides best performance for batteries with 100mAhr to 6Ahr
capacity.
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 stateof-charge (SOC) in percentage (%) and remaining capacity in milliampere-hours (mAh) 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.
For even better fuel-gauging accuracy than ModelGauge m5 EZ, contact Maxim for information regarding cell
characterization.
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.
www.maximintegrated.com
Maxim Integrated | 14
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
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.
Table 2. ModelGauge m5 Register Standard Resolutions
REGISTER
TYPE
LSb
SIZE
MINIMUM
VALUE
MAXIMUM
VALUE
Capacity
0.5mAh
0.0mAh
32767.5mAh
Percentage
1/256%
0.0%
255.9961%
www.maximintegrated.com
NOTES
1% LSb when reading only the upper byte.
Maxim Integrated | 15
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Table 2. ModelGauge m5 Register Standard Resolutions (continued)
REGISTER
TYPE
LSb
SIZE
MINIMUM
VALUE
MAXIMUM
VALUE
Voltage
1.25mV/
16
0.0V
5.11992V
Current
156.25μA
-5.12A
5.12A
Temperature
1/256°C
-128.0°C
127.996°C
Resistance
1/4096Ω
0.0Ω
15.99976Ω
Time
5.625s
0.0s
102.3984h
NOTES
Signed two's-complement format.
Special
Signed two's-complement format. 1°C LSb when reading only the
upper byte.
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. The IC provides best performance for batteries with
100mAhr to 6Ahr capacity.
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.
www.maximintegrated.com
Maxim Integrated | 16
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
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
D3
D2
D1
D0
0
1
0
0
ModelID
Refresh: Set Refresh to 1 to command the model reload. After completion the MAX17262 clears Refresh to 0.
R100: if using 100kΩ NTC, set R100 = 1; if using 10kΩ NTC, set R100 = 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 (500mA)
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. (One task period is 175ms in active mode, and 5.6 seconds
in hibernate mode by default.) 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
Table 6. Config2 (BBh) Format
D15
D14
D13
www.maximintegrated.com
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Maxim Integrated | 17
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Table 6. Config2 (BBh) Format (continued)
0
0
AtRateEn
DPEn
POWR
dSOCen
TAlrtEn
LDMdl
1
DRCfg
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.
POWR: Sets the time constant for the AvgPower register. The default POR value of 0100b gives a time constant of
www.maximintegrated.com
Maxim Integrated | 18
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
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 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.
www.maximintegrated.com
Maxim Integrated | 19
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
RSENSE
CURRENT
INTEGRATOR
ModelGauge
ALGORITHM
COULOMB
COUNTER
Q CHANGE
%SOC CHANGE
CAPACITY
MICROCORRECTIONS
FULL, EMPTY, AND
STANDBY-STATE
DETECTION UNNECESSARY
Figure 2. ModelGauge m5 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.
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.
www.maximintegrated.com
Maxim Integrated | 20
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
RepSOC Register (06h)
Register Type: Percentage
RepSOC is the reported state-of-charge percentage output for use by the application user interface.
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.
www.maximintegrated.com
Maxim Integrated | 21
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Vmn and Vmx (Minimum/Maximum Voltage-Alert Threshold Exceeded): These bits are set to 1 whenever a VCell
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-gauge algorithm to predict cell
capacity and also made available to the user.
Voltage Measurement
VCell Register (09h)
Register Type: Voltage
VCell reports the voltage measured between BATT and GND.
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.
www.maximintegrated.com
Maxim Integrated | 22
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Table 8. MaxMinVolt (1Bh) Format
D15
D14
D13
D12
D11
D10
MaxVCELL
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
MinVCELL
MaxVCELL: Maximum VCell register reading
MinVCELL: Minimum VCell register reading
Current Measurement
The MAX17262 monitors the current flow through the battery by measuring the voltage across the internal current
sensing element. 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.
The maximum current constraints listed in the Absolute Maximum Ratings section should be followed to ensure the
100,000 hours lifetime of the sensing element. In general, the root mean square of current over whole lifetime should
below 1.7A, with additional limitation on peak value based on utilization. If the device utilization is 100% (charges or
discharges at highest allowable current level without stopping), then the maximum DC current rating is 1.7A. If the device
utilization is 10%, then the maximum DC current allowed is 2.4A. For example, it spends 10% of its time charging, and
the remaining 90% resting or discharging, then it can be allowed 2.4A charge current, but discharge currents should be
below 1.6A. For Pulse current case, if the utilization of the current pulse is 1% of whole lifetime, then the peak pulse
current allowed with 250ms pulse width and 10% duty cycle is 3.1A. The utilization patterns are visualized in Figure 3.
www.maximintegrated.com
Maxim Integrated | 23
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
3.1A PULSED CURRENT, 10% DUTY,
1% OF LIFETIME
2.4A LIMIT 10% OF LIFETIME
1.7A CONTINUOUS CURRENT LIMIT
1.6A LIMIT FOR 90% OF LIFETIME
1.68A CONTINUOUS CURRENT
IN THE REST 99% OF LIFETIME
Figure 3. Current Limit Based On Utilization Patterns
Current Register (0Ah)
Register Type: Current
The MAX17262 uses internal current sensing to monitor the current through the SYS pin. The measurement value
is stored in two's-complement format. Measurement that exceeds maximum and minimum current range is stored as
maximum and minimum value. The current register has a LSB value of 156.25μA, a register scale range of ± 5.12 A, and
an allowable measurement range as described in the Absolute Maximum Ratings.
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
www.maximintegrated.com
Maxim Integrated | 24
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
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
currents are each stored as two’s complement 8-bit values with 160mA resolution. Table 9 shows the register format.
Table 9. MaxMinCurr (1Ch) Format
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
MaxCurrent
D5
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 10 shows the format of the
register.
www.maximintegrated.com
Maxim Integrated | 25
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Table 10. MaxMinTemp (1Ah) Format
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
MaxTemperature
D4
D3
D2
D1
D0
MinTemperature
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 1.6mW.
AvgPower Register (B3h)
Filtered average power from the Power register. LSB is 1.6mW.
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: (VTH > VBATT – VDET) and battery removal detection enabled (Ber = 1).
• Battery insertion: (VTH < VBATT – 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 11 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.
www.maximintegrated.com
Maxim Integrated | 26
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Table 11. VAlrtTh (01h) Format
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
VMAX
D4
D3
D2
D1
D0
VMIN
VMAX: Maximum voltage reading. An alert is generated if the VCell register reading exceeds this value.
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 12) 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 two’s-complement format with 1°C resolution over the full operating range of the Temp register.
Table 12. 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 13) 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 13. SAlrtTh (03h) Format
D15
D14
D13
D12
SMAX
D11
D10
D9
D8
D7
D6
D5
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 14) 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 80mA resolution over the full operating range of the Current register.
www.maximintegrated.com
Maxim Integrated | 27
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Table 14. IAlrtTh (B4h) Format
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
IMAX
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.
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 15. 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 16. 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
www.maximintegrated.com
QRTable20 QRTable30
Maxim Integrated | 28
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Table 16. ModelGauge m5 Register Memory Map (continued)
PAGE/
WORD
00h
10h
20h
30h
40h
B0h
D0h
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
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 4 is essential for voltage, temperature, and current measurement accuracy. The
recommended layout guidelines are as follows:
● REG capacitor trace loop area should be minimized. REG should be connected to the GND pin as close as possible
to the IC. This helps filter any noise from the internal regulated supply.
www.maximintegrated.com
Maxim Integrated | 29
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
PACK +
SYSPWR
CBATT
TH
BATT
NC
SCL
ALRT
SYS
SDA
REG
GND
MAX17262
CREG
PACK -
SYSGND
Figure 4. MAX17262 Layout Guide
www.maximintegrated.com
Maxim Integrated | 30
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Ordering Information
PART NUMBER
TEMP RANGE
DESCRIPTION
PIN-PACKAGE
MAX17262REWL+
-40°C to +85°C
Single-Cell, Internal Sensing
9-WLP
MAX17262REWL+T
-40°C to +85°C
Single-Cell, Internal Sensing
9-WLP
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
www.maximintegrated.com
Maxim Integrated | 31
MAX17262
5.2μA 1-Cell Fuel Gauge with ModelGauge m5 EZ
and Internal Current Sensing
Revision History
REVISION
NUMBER
REVISION
DATE
0
7/18
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.
© 2018 Maxim Integrated Products, Inc.
工商网监
湘ICP备2023018690号
