DS2784G+ Maxim Integrated Products, DS2784G+ Datasheet - Page 20

• Manufacturer Part Number: DS2784G+
• Description: IC FUEL GAUGE STND-ALONE 14-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of DS2784G+

• Function: Fuel, Gas Gauge/Monitor
• Battery Type: Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
• Voltage - Supply: 2.5 V ~ 4.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 14-TDFN
• Product: Fuel Gauges
• Operating Supply Voltage: 2.5 V to 4.6 V
• Supply Current: 85 uA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Charge Safety Timers: Yes
• Mounting Style: SMD/SMT
• Temperature Monitoring: Yes
• Uvlo Start Threshold: 2.4 V
• Uvlo Stop Threshold: 2.5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Read and write access is allowed to the ACR. The ACR must be written MSB first then LSB. Whenever the ACR is
written, the fractional accumulation result bits are cleared. The write must be completed in 3.5s (one ACR update
period). A write to the ACR forces the ADC to perform an offset correction conversion and update the internal offset
correction factor. The current measurement and accumulation begin with the second conversion following a write to
the ACR.
The ACR value is backed up to EEPROM in case of power loss. The ACR value is recovered from EEPROM on
power-up. See Table 8 for specific address location and backup frequency.
ACCUMULATED CURRENT REGISTER FORMAT
Table 5. Resolution and Range vs. Sense Resistor
ACCUMULATION BIAS
In some designs a systematic error or an application preference requires the application of an arbitrary bias to the
current accumulation process. The current accumulation bias register (CAB) allows a user-programmed constant
positive or negative polarity bias to be included in the current accumulation process. The value in CAB can be used
to estimate battery currents that do not flow through the sense resistor, estimate battery self-discharge or estimate
current levels below the current measurement resolution. The user programmed two’s complement value, with bit
weighting the same as the current register, is added to the ACR once per current conversion cycle. The CAB is
loaded on power-up from EEPROM memory.
The difference between the CAB and COB is that the CAB is not subject to current blanking. Offset currents
between 100µV and -25µV are not accumulated if the offset is made by the COB. Offset currents between 100µV
and -25µV are accumulated if they are made by the CAB.
CURRENT ACCUMULATION BIAS REGISTER FORMAT
MSb
Current Resolution
Current Range
ACR Resolution
ACR Range
2
15
2
14
MSB—ADDRESS 10h
2
13
2
12
2
11
“S”: Sign Bit
MSb
409.6mVh
2
V
1.5625V
±51.2mV
6.25Vh
S
10
SS
- V
2
2
SNS
9
6
LSb
2
2
5
8
20 of 43
ADDRESS 61h
312.5Ah
78.13A
20.48Ah
±2.56A
20m
2
4
MSb
2
2
3
7
Units: 1.5625V/R
416.7Ah
104.2A
27.31Ah
2
2
±3.41A
15m
2
6
LSB—ADDRESS 11h
2
2
1
5
R
LSb
SNS
2
2
SNS
0
4
156.3A
40.96Ah
625Ah
±5.12A
10m
2
3
Units: 6.25Vh/R
2
2
1.250mAh
312.5A
±10.24A
81.92Ah
5m
2
1
LSb
2
SNS
0