Hi Victor,
As this system is DC coupled then implementing active filters can affect the RL path. the internal amplifier (Figure 56 of ADAS100 Rev B datasheet) is included on chip to increase gain. Correct you need to size your gain to esure the input range is not saturated. Rather than use an active filter externally I would recommend using the internal gain setting to see if you can achieve the resolution needed.
Regards,
Padraic