The EFM8 Laser Bee 1 reference manual mentions the ADC has "high quality" inputs in section 12.3.1. How are these inputs better than the normal inputs?
Please refer to the ADC's Input Pin Capacitance and Input Mux Impedance specification in the datasheet table 4.9. Specifications for both the high quality and normal inputs are listed.
As of revision 0.5 of the datasheet, these have specifications of "TBD".