DS2746G+ Maxim Integrated Products, DS2746G+ Datasheet - Page 6

• Manufacturer Part Number: DS2746G+
• Description: IC MON BATTERY 2-WIRE 10-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of DS2746G+

• 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: 10-WFDFN Exposed Pad
• Operating Supply Voltage: 2.5 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Charge Safety Timers: No
• Mounting Style: SMD/SMT
• Temperature Monitoring: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DS2746 Low-Cost 2-Wire Battery Monitor
Figure 3. Block Diagram
DETAILED DESCRIPTION
The DS2746 operates either in active mode where cell voltage, system current, and auxiliary inputs are monitored,
or in a low power sleep mode to conserve energy when the system is idle. While in active mode, the DS2746
contantly measures current flow through an external sense resistor. Each current measurement is reported with
sign and magnitude in a two-byte Current register. Offset bias and offset blanking features remove offset error from
the current A/D to improve measurement accuracy. Each current measurement is integrated into the Accumulated
Current register (ACR) to maintain a sum of all charge entering and exiting the cell.
The DS2746 has two auxiliary inputs to allow voltage sampling of resistor divider circuits. These can be used to
measure a thermistor or an ID resistor located inside the battery pack. The V
output provides the pullup voltage
OUT
for the resistor divider networks. The DS2746 disables V
after measuring the auxiliary inputs to reduce power
OUT
use by the measurement system. V
operation can be disabled through software to further reduce power
OUT
consumption when the auxiliary inputs are not in use.
A dedicated voltage A/D measures voltage of the cell and the auxiliary inputs. A mux on the input to the A/D cycles
through the V
, AIN0, and AIN1 pins repeatedly in that order. An internal reference is used to measure V
voltage.
IN
IN
AIN0 and AIN1 are measured as a percentage of V
. This ratiometric measurement of the Auxiliary inputs
OUT
prevents noise in the supply from affecting accuracy of the readings
The DS2746 measurements can be used directly to provide accurate fuel gauging in typical use conditions, or
along with FuelPack™ algorithms to form a complete and accurate solution for estimating remaining capacity over
wide temperature and operating conditions.
Through its 2-Wire interface, the DS2746 allows a host system read/write access to the Status/Configuration
register and Measurement registers. If sleep mode operation is enabled, holding both interface lines low forces the
DS2746 into a low power sleep mode where A/D measurements are paused and the ACR register is maintained.
FuelPack is a trademark of Maxim Integrated Products, Inc.
6 of 17