DS2786BG+T&R Maxim Integrated Products, DS2786BG+T&R Datasheet - Page 15

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

Specifications of DS2786BG+T&R

• 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

Figure 20. Learn Delta Percent Threshold
The learn delta percent threshold allows the application
to select how large a cell capacity change is required
before the new cell-capacity value is learned. The dif-
ference between the present OCV measurement and
the last OCV measurement must be greater than the
learn delta percent threshold value for a learn to occur.
This prevents IC measurement resolution from adding
error to the learned cell-capacity value. It is recom-
mended this register be set to a value of at least 50%.
Figure 20 shows the learn delta percent threshold.
The DS2786B has memory space with registers for instru-
mentation, status, and control. When the MSB of a 2-byte
register is read, both the MSB and LSB are latched and
held for the duration of the read data command to pre-
vent updates during the read and ensure synchronization
between the 2 register bytes. For consistent results,
Figure 21. EEPROM Access Through Shadow RAM
MSB
2
7
2
6
2
5
INTERFACE
______________________________________________________________________________________
SERIAL
ADDRESS 7Eh
2
4
Stand-Alone OCV-Based Fuel Gauge
2
3
READ
Memory Map
2
2
UNITS: 0.5%
2
1
WRITE
LSB
2
0
always read the MSB and the LSB of a 2-byte register
during the same read data command sequence.
Memory locations 60h through 7Fh are EEPROM stor-
age locations. EEPROM memory is shadowed by RAM
to eliminate programming delays between writes and to
allow the data to be verified by the host system before
being copied to EEPROM. The read data and write data
protocols to/from EEPROM memory addresses access
the shadow RAM. Setting the RCALL bit in the
Command Register (FEh) initiates data transfer from the
EEPROM to the shadow RAM. See Figure 21.
Setting the COPY bit in the Command Register initiates
data transfer from the shadow RAM to the EEPROM. An
external voltage supply must be provided on the
V
requires the COPY bit be reset to zero within the t
time window to properly program EEPROM. Resetting
COPY too soon might prevent a proper write of the
cells. Resetting COPY too late might degrade EEPROM
copy endurance.
The DS2786B uses shadow RAM data for fuel-gauge
calculations. Fuel-gauge information can be changed in
the application by writing the shadow RAM locations.
Afterwards, the SOCV bit should be written to reset the
fuel gauge. Note that any reset of the IC causes the
shadow RAM data to be restored from EEPROM.
PROG
SHADOW
EEPROM
pin prior to writing the COPY bit. The DS2786B
RECALL
COPY
PROG
15