DS2756E+ Maxim Integrated Products, DS2756E+ Datasheet - Page 7

• Manufacturer Part Number: DS2756E+
• Description: IC FUEL GAUGE BATT 8TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of DS2756E+

• Function: Fuel, Gas Gauge/Monitor
• Battery Type: Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP
• Operating Supply Voltage: 3 V to 5.5 V
• Supply Current: 75 uA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Charge Safety Timers: Yes
• Mounting Style: SMD/SMT
• Temperature Monitoring: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

error is introduced into both the Average Current and Accumulated Current values by the current sample timing
discontinuity introduced with each trigger of the Snapshot mode, use of Snapshot once every 5s does not produce
a significant error.
The following register formats specify the update interval and units for the Current and Average Current registers.
Values are posted in two’s complement format. Positive values represent charge currents (V
values represent discharge currents (V
at the maximum value, 0x7FFF. Negative currents below the minimum register value are reported at the minimum
value, 0x8000.
Figure 3. Current Register Format
Figure 4. Average Current Register Format
CURRENT OFFSET CORRECTION
Continuous offset cancellation is performed automatically to correct for offsets in the current measurement system.
Individual values reported by the Current register have a maximum offset of ±0.5 LSb’s (±7.8125V). Individual
values reported in the Average Current register have a maximum offset of ±2 LSb’s (±7.8125V).
CURRENT ACCUMULATION
The DS2756 measures current for coulomb counting purposes, with an accuracy of ±2% (±3.9V) over a range of
±64mV. Using a 20m sense resistor, current accumulation is performed over a range of ±3.2A while measuring
standby currents with an accuracy of ±195A. Current measurements are internally summed, or accumulated, with
the results displayed in the Accumulated Current Register (ACR). The accuracy of the ACR is dependent on both
the current measurement and the accumulation timebase. The 16-bit ACR has a range of ±204.8mVh with an LSb
of 6.25Vh. Accumulation of charge current above the maximum register value is reported at the maximum value;
conversely, accumulation of discharge current below the minimum register value is reported at the minimum value.
Read and write access is allowed to the ACR. The ACR must be written MSB first then LSB. Whenever the ACR is
written, internal fractional accumulation result bits are cleared. In order to preserve the ACR value in case of power
loss, the ACR MSB and LSB are automatically backed up to EEPROM after incrementing or decrementing by
100Vh (5.0mAh for R
12-bit + sign resolution (13-bit), 88ms update interval
MSb
“S”: sign bit(s)
15-bit + sign resolution (16-bit), 2.8s update interval
MSb
“S”: sign bit(s)
S
S
2
2
11
14
MSB-Address 0Eh
MSB-Address 1Ah
2
2
SNS
10
13
= 20m). The ACR value is recovered from EEPROM on power-up or by a Recall Data
2
2
12
9
2
2
11
8
IS2
2
2
10
7
> V
IS1
2
2
6
9
). Positive currents above the maximum register value are reported
LSb
LSb
2
2
5
8
7 of 27
15.625V/Rsns
MSb
MSb
2
2
4
7
2
2
3
6
LSB-Address 0Fh
LSB-Address 1Bh
2
2
2
5
2
2
Units:2
Units: 2
1
4
2
2
0
3
0
0
= 1.953V/R
2
X
IS1
2
> V
2
X
1
IS2
) and negative
LSb
LSb
SNS
2
X
0
=