BQ40Z50: current tolerance of ADC (software)

Hi Cheer,
There is a specification for the Coulomb Counter error in the data sheet, but this is just for the chip. The actual accuracy will be heavily dependent on your board, sense resistor and temperature drift specification of your sense resistor.
Assuming you are using a 1mOhm sense resistor.
The max offset error of the ADC will be 5uV, so the max offset error for a 1mOhm sense resistor will be 5mAmps.
The gain error can be a maximum of 0.8%, so at 2000mAmps and 1mOhm sense resistor, the max error will be 16+5 = 21mAmps.
At 10000mAmps, the max error can be 80+5 = 85mAmps.
Typically there is also an auto calibration, that will remove most of the offset error, and also, the example mentioned above is an extreme case. So we normally see an error of about +-10mAmps through the range of 2000 to 10000mAmps.
It is also important to note that this does not cause any big issues in gauging, and you will still typically see a 1% gauging accuracy even if there are small errors in the current measurement, because the bq40z50 does not rely only on the current measurement for it's accuracy.
Regards,
Swami