RC filter for PSOC ADCs

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
jakac_1482786
Level 3
Level 3
First like received

I have a quick question for an analog circuit that is low frequency.  I am implementing a PH meter that is reading a voltage from a probe (that is a very low current battery). It is amplified by a TI LMP91200 opamp and then sent to the delSig (at 16 bit, 200k sps with bypass cap).  I was going to put RC filters on the inputs to block some noise coming from switching power supplies, etc. Can someone recommend a good set of R and C values for this?  is this even necessary?

0 Likes
1 Solution
odissey1
Level 9
Level 9
First comment on KBA 1000 replies posted 750 replies posted

jasonkahana,

AFAIK, a PH meter sensor is slow-responce (seconds). There is no need for 200kHz sampling rate.

Second, analog front end has nothing to do with PSoC, you need to refine it separately.

/odissey1

View solution in original post

0 Likes
2 Replies
RyanZhao
Moderator
Moderator
Moderator
250 sign-ins First question asked 750 replies posted

what is the frequency of the input signal and the frequency of the noise coming from switching power supplies?

0 Likes
odissey1
Level 9
Level 9
First comment on KBA 1000 replies posted 750 replies posted

jasonkahana,

AFAIK, a PH meter sensor is slow-responce (seconds). There is no need for 200kHz sampling rate.

Second, analog front end has nothing to do with PSoC, you need to refine it separately.

/odissey1

0 Likes