DS2745U+ Maxim Integrated Products, DS2745U+ Datasheet - Page 10

• Manufacturer Part Number: DS2745U+
• Description: IC BATT MONITOR I2C 8-UMAX
• Manufacturer: Maxim Integrated Products

Specifications of DS2745U+

• Function: Fuel, Gas Gauge/Monitor
• Battery Type: Lithium-Ion (Li-Ion); Nickel-Metal Hydride (NiMH)
• Voltage - Supply: 2.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Product: Fuel Gauges
• Operating Supply Voltage: 2.5 V to 5.5 V
• Supply Current: 70 uA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Charge Safety Timers: No
• Mounting Style: SMD/SMT
• Temperature Monitoring: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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DS2745 Low-Cost I
C Battery Monitor
CURRENT BLANKING
The Current Blanking feature modifies current measurement result prior to being accumulated in the ACR. Current
Blanking occurs conditionally when a current measurement (raw current + COBR) falls in one of two defined
ranges. The first range prevents charge currents less than 100V from being accumulated. The second range
prevents discharge currents less than 25V in magnitude from being accumulated. Charge current blanking is
always performed, however, discharge current blanking must be enabled by setting the NBEN bit in the
Status/Config register. See the register description for additional information.
ACCUMULATION BIAS
The Accumulation Bias register (ABR) allows a programmable offset value to be added to the current accumulation
process. The new ACR value results from the addition of the Current register value plus ABR plus the previous
ACR value. ABR can be used to intentionally skew the current accumulation to estimate system stand-by currents
that are too small to measure. ABR value is not subject to the Current Blanking thresholds.
Read and write access is allowed to the ABR. Whenever the ABR is written, the new value is applied to all
subsequent current measurements. ABR can be set to any value between +198.1V and -199.7V in 1.56V
steps. The ABR value is stored as a two’s complement value in volatile memory, and must be initialized via the
interface on power-up. Figure 9 describes the ABR address, format, and resolution.
Figure 9. ACCUMULATION BIAS REGISTER FORMAT
Address 62
6
5
4
3
2
1
0
S
2
2
2
2
2
2
2
MSb
LSb
“S”: sign bit
Units:
1.56V/Rsns
MEMORY
The DS2745 has memory space with registers for instrumentation, status, and control. When the MSB of a two-
byte register is read, both the MSB and LSB are latched and held for the duration of the read data command to
prevent updates during the read and ensure synchronization between the two register bytes. For consistent results,
always read the MSB and the LSB of a two-byte register during the same read data command sequence.
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