DS2786BG+ Maxim Integrated Products, DS2786BG+ Datasheet - Page 13

• Manufacturer Part Number: DS2786BG+
• Description: IC FUEL GAUGE OCV-BASED 10-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of DS2786BG+

• Function: Fuel, Gas Gauge/Monitor
• Battery Type: Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
• Voltage - Supply: 2.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-TDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The OCV cell model is a 9-point piece-wise linear
approximation of open-circuit cell voltage vs. the
remaining capacity of the cell. Whenever an OCV
update occurs, the Relative Capacity Register is adjust-
ed to a new value based on the OCV voltage reading
and a linear approximation of the table values. Figure 15
shows the factory-default cell model stored in EEPROM.
The OCV cell model can be modified by changing the
Capacity and Voltage Breakpoint Registers in EEPROM.
Capacity 0 is fixed at 0% and cannot be changed.
Capacity 1 through Capacity 7 are stored with 0.5%
resolution at addresses 61h through 67h, respectively.
Figure 15. DS2786BG-C3 OCV Cell Model
Figure 16. Capacity 1 to Capacity 7 Registers Format
100%
BREAKPOINT 8
4.171V
100%
______________________________________________________________________________________
BREAKPOINT 6
80%
4.042V
85%
Stand-Alone OCV-Based Fuel Gauge
OCV Cell Model
MSB
2
7
BREAKPOINT 7
BREAKPOINT 5
4.087V
90.5%
2
6
4.005V
80%
60%
2
5
ADDRESS 61h–67h
2
4
2
Capacity values must be monotonic (Capacity 1 >
Capacity 0, Capacity 2 > Capacity 1, etc.), but other-
wise can be written to any value between 0.5% to
99.5%. Capacity 8 is fixed at a value of 100% and can-
not be changed. See Figure 16.
Voltage breakpoints require 2 bytes per breakpoint, but
are otherwise stored in a similar manner: voltage break-
point 0: MSB stored at address 68h, LSB stored at
address 69h. Other voltage breakpoints are stored
sequentially through address location 79h. Each volt-
age breakpoint has a resolution of 1.22mV, and a range
from 0.0V to 4.996V. Voltage breakpoint values must
also be monotonic. Figure 17 is the Voltage Breakpoint
Register format.
3
40%
BREAKPOINT 4
2
2
BREAKPOINT 3
3.831V
52.5%
3.752V
25%
UNITS: 0.5%
2
1
LSB
2
0
20%
BREAKPOINT 1
BREAKPOINT 0
3.619V
3.186V
BREAKPOINT 2
5%
0%
3.673V
10%
0%
4.2
4.0
3.8
3.6
3.4
3.2
3.0
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