GENERAL DESCRIPTION

The DS2746 provides system-side battery capacity monitoring in cost-sensitive applications. Voltage, bidirectional current, and accumulated current measurement data is provided to the host processor over a 2-wire interface. Offset bias and offset blanking features greatly enhance the accuracy of the coulomb counter. In addition, the DS2746 has two auxiliary A/D inputs to sample the pack identification resistor, thermistor, or other voltage source. The results are reported as a ratiometric fraction of the supply voltage eliminating error related to the supply. The DS2746 reduces the total power consumption of the measurement circuit by enabling the resistor dividers, through the VOUT pin, only while measurements are made. When the system is inactive, a low power sleep mode reduces current consumption while maintaining the coulomb count. The tiny 3mm × 3mm TDFN package consumes only 9mm2 of PCB space.

FEATURES

14-Bit Bidirectional Current Measurement

  - 6.25μV LSB, ±51.2mV Dynamic Range

  - 416.7μA LSB, ±3.4A Range (RSNS = 15mΩ)

Current Accumulation Register Resolution

  - 6.25μVhr LSB, 409.6mVh Range

  - 417μAhr LSB, 27.31Ah Range

11-Bit Battery Voltage Measurement

  - 2.44mV LSB, 0V to 4.997V Input Range

  - ±10mV Accuracy at 3.6V Input

Two 11-Bit Aux Input Voltage Measurements

  - Ratiometric Inputs Eliminate Supply Error

  - VOUT drives Dividers, Reduces Power

  - ±8 LSB Accuracy

Low Power Consumption:

  - Active Current: 70μA typical, 100μA max

  - Sleep Current: 1μA typical, 3μA max

APPLICATIONS

2.5G/3G Wireless Handsets

PDA/Smartphones

Digital Still and Video Cameras

Handheld Computers and Terminals