I am measuring analog DC voltage at the analog pin of dspic33 series microcontroller. The source of the signal is AC. So, I rectified it with diodes and amplify it with op-amps. In order to reduce the ripple I am using RC filter as first phase filtering and LC filter as second phase filtering.
Single RC filter cannot satisfy my need that it outputs a voltage with 100mv of ripple content in a signal which is going to be measured by ADC. Also, I cannot increase the capacitance since it violates my timing constraints of the requirement due to high RC time constant. So, I decided to go for LC filter as second phase filtering to reduce the ripple content of the DC signal.
My doubt is, whether using LC filter near the analog pin of microcontroller is technically ok or not? Is there any interference come with LC filter when the setup undergoes environmental tests and noise tests?
RC filter has 1k ohm resistance and 1uF capacitance. LC filter has 470 mH inductance and 1 uF capacitance.
Edit : I have added filter portion of the schematic. As per comments I need to clarify my points.
Input to the circuit is AC (0 - 200V) The output of the circuit is DC (0 - 3.3V)
Timing constraint means, I need to detect the voltage within certain milli seconds to process and do other actions based on this value within a second.