BQ2085 Datasheet, PDF (52/56 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

bq2085
SLUS541 – OCTOBER 2002
APPLICATION INFORMATION
The internal oscillator performance also depends on the tolerance of the 113k resistor connected between
RSOC (pin 33) and VSSA (pin 34). It is recommended that this resistor be placed as close to the bq2085 as
possible and that it have a specification of ±0.1% tolerance and ±50 ppm temperature drift or better. The layout
of the PCBA is also an additional contributing factor to performance degradation.
The average temperature drift error of the oscillator function over a learning charge or discharge cycle
introduces an equal capacity prediction error in a learned full charge capacity (FCC).
Figure 10 shows a typical bq2085-based battery pack application. The circuit consists of the bq29311 analog
front end (AFE) IC, LED display, temperature measurement network, data flash connections, serial port, and
the sense resistor. The data flash stores basic battery pack configuration information and measurement
calibration values. The data flash must be programmed properly for bq2085 operation. Table 13 shows the data
flash memory map and outlines the programmable functions available in the bq2085.
52
www.ti.com