Other Parts Discussed in Thread: BQ25898, BQ25896, BQ25895, BQ25898D, BQ25898C, BQ25892, , , BQ25895M
When only the battery is present, ADC monitoring works only when the battery voltage is above the MINSYS register setting. The purpose is to save the battery energy when the remaining capacity is relatively low. This applies for BQ25890, BQ25890H, BQ25892, BQ25895, BQ25895M, BQ25896, BQ25898, BQ25898D, BQ25898C.
In battery only mode, the ADC is only functional if the battery voltage is higher than the MINSYS register setting (REG03[1:3]). Otherwise, the ADC readings are not valid. For the maximum ADC operating range with VBAT only, user may set the MINSYS voltage to its lowest setting (i.e. 3.0V) so that the ADC functions down to VBAT=3.0V.