DS2786BG+T&R Maxim Integrated Products, DS2786BG+T&R Datasheet - Page 10

• 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

Stand-Alone OCV-Based Fuel Gauge
The DS2786B uses an integrated temperature sensor to
measure battery temperature with a resolution of
0.125°C. Temperature measurements are updated
every 1760ms and placed in the Temperature Register
in two’s-complement form. The format of the
Temperature Register is shown in Figure 7. The ITEMP
bit in the Status/Configuration Register must be set to
enable the internal temperature measurement instead
of the AIN1 measurement.
In the Active Mode of operation, the DS2786B continu-
ally measures the current flow into and out of the bat-
tery by measuring the voltage drop across a low-value
current-sense resistor, R
SNS and V
SNS and V
ues occur when V
current values occur when V
Peak signal amplitudes up to 102mV are allowed at the
Figure 7. Temperature Register Format
Figure 8. Current Register Formats
Table 1. Current Range and Resolution for Various R
10
MSB
“S”: SIGN BIT, “X”: RESERVED
MSB
“S”: SIGN BIT, “X”: RESERVED
|V
S
S
SS
______________________________________________________________________________________
25μV
- V
SNS
2
2
SS
10
9
SS
Temperature Measurement
|
CURRENT RESOLUTION (1 LSB)
is ±51.2mV. Note that positive current val-
pins. The voltage-sense range between
2
1.25mA
2
20m
8
9
MSB—ADDRESS 0Ah
MSB—ADDRESS 0Eh
SNS
Current Measurement
2
is less than V
2
7
8
SNS
1.667mA
15m
, connected between the
SNS
2
2
6
7
R
SNS
is greater than V
2
2
SS
5
2.5mA
6
10m
, and negative
2
2
4
5
LSB
LSB
5m
5mA
2
2
3
4
SS
.
input as long as the continuous or average signal level
does not exceed ±51.2mV over the conversion-cycle
period. The ADC samples the input differentially and
updates the Current Register every 880ms at the com-
pletion of each conversion cycle. Figure 8 describes
the Current Measurement Register format and resolu-
tion for each option. Charge currents above the maxi-
mum register value are reported at the maximum value
(7FFFh = +51.2mV). Discharge currents below the mini-
mum register value are reported at the minimum value
(8000h = -51.2mV).
Every 1024th conversion, the ADC measures its input
offset to facilitate offset correction to improve current
accuracy. Offset correction occurs approximately every
15min. The resulting correction factor is applied to the
subsequent 1023 measurements. During the offset cor-
rection conversion, the ADC does not make a measure-
ment. The current measurement just prior to the offset
conversion is displayed in the Current Register. See
Table 1 for current range and resolution for various
R
MSB
MSB
SNS
V
2
2
±51.2mV
SS
2
3
values.
- V
SNS
SNS
2
2
1
2
Values
CURRENT INPUT RANGE
2
2
±2.56A
0
1
20m
LSB—ADDRESS 0Bh
LSB—ADDRESS 0Fh
2
X
0
±3.41A
15m
X
X
R
SNS
X
X
UNITS: 25μV/R
±5.12A
10m
UNITS: 0.125°C
X
X
±10.24A
LSB
LSB
5m
SNS
X
X