I would like to filter signal on ADC input. My question is if I can add before input ordinary RC filter. I suppose that this is not good idea. I have to limit number of operational amplifiers on the board so it can't be isolated by buffer amplifier.
If resistance is too big the internal (S&H) capacitor will not fully recharge. Capacitor from RC filter will be parallel with capacitor from S&H and it will change the capacitance of sampling capacitor? Am I right or not ?