DS2786G-5+T&R Maxim Integrated Products, DS2786G-5+T&R Datasheet - Page 10

• Manufacturer Part Number: DS2786G-5+T&R
• Description: IC FUEL GAUGE OCV-BASED 10-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of DS2786G-5+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

Table 1. Current Range and Resolution for Various R
CURRENT OFFSET BIAS
The Current Offset Bias Register (COBR) allows a programmable offset value to be added to raw current
measurements. The result of the raw current measurement plus the COBR value is displayed as the current
measurement result in the Current Register, and is used for current accumulation and detection of an OCV
condition. The COBR value can be used to correct for a static offset error, or can be used to intentionally skew the
current results and therefore the current accumulation.
Read and write access is allowed to COBR. Whenever the COBR is written, the new value is applied to all
subsequent current measurements. COBR can be programmed in 25V steps to any value between +3.175mV
and -3.2mV. The COBR value is stored as a two’s complement value in nonvolatile (NV) memory. The COBR
factory default value is 00h.
Figure 9. Current Offset Bias Register Format
CURRENT ACCUMULATION
An Internal Accumulated Current Register (IACR) serves as an up/down counter holding a running count of charge
since the last OCV condition. Current measurement results, plus a programmable bias value are internally
summed, or accumulated, at the completion of each current measurement conversion period. The IACR has a
range of ±204.8mVh. The IACR uses the Initial or Learned Cell Capacity Registers to increment or decrement the
Relative Capacity Register as current flows into or out of the battery. In this way, the fuel gauge is accurate even
when an OCV condition does not occur for an extended time period.
Table 2. Accumulated Current Range for Various R
CURRENT RESOLUTION (1 LSB)
CURRENT INPUT RANGE
±204.8mVh
V
SS
|V
- V
V
±51.2mV
SS
SS
25V
SNS
- V
- V
SNS
SNS
|
“S”: sign bit
MSb
±10.24Ah
S
20m
1.25mA
2
±2.56A
20m
20m
6
IACR RANGE
2
5
10 of 22
±13.65Ah
Address 60h
15m
2
1.667mA
4
±3.41A
15m
15m
Units:
2
3
R
SNS
SNS
R
SNS
R
2
DS2786 Stand-Alone OCV-Based Fuel Gauge
SNS
SNS
2
±20.48Ah
Values
25V/R
10m
2.5mA
Values
±5.12A
10m
10m
2
1
LSb
SNS
2
0
±40.96Ah
±10.24A
5m
5mA
5m
5m