@Ivy: Yep, that is what I am doing. Have a look at the additional points I added at my "solution". ( de.wikipedia.org/wiki/RC-Glied#/media/File:Tiefpass.svg ). Note: The RC-Lowpass should provide enough current (R = U/I) to power up your LED AND the FC1816. Something like this (R = U/I with U = 0,5 I = 0,003 or maybe I = 0,020=> 25-160Ohms). Choose the resistor lower like maybe 10Ohm with led or 100ohm wihtout). This will lower the noise in the power supply for the FC1816 further. Note that I used 5V as VCC and 5-0,5 = 4,5V is still plenty. So be carefull if you only use 3.3V