Hello,
I am designing a front end drive circuit for the ADS7066 to read ~6 photodiodes in parallel. The level of illumination on my photodiode changes every ~0.0316 seconds, giving me an input frequency of ~32Hz.
That being said, I understand that it is necessary to oversample to get a reliable result, so I (arbitrarily) applied a factor of 50 and assumed a sample rate of 1.6kSPS. As I mentioned, I will be using ~6 of the ADC channels, so the overall sample rate would be 9.6kHz (I believe).
I am trying to figure out what size of Rfilt and Cfilt I need on my driver. I used the SAR ADC front-end driver design precision labs video as well as the calculator tool, but where I'm getting hung up is the Tacq. From what I've gathered, my Tacq will be:
Tacq = 1/fsample - tconvmax = 1/(9.6kHz) - 3200ns = ~100us
Using the calculator tool, this gives me a Rfilt minimum of 5.135kOhms. This seems very large to me. My question is, am I thinking about this wrong? Did I arrive at my Tacq incorrectly?
Thank you very much for your insight,
Austin Allen