Part Number:LMP91051
Good evening,
I've been implementing the application notes that can be found here, as to put together a CO2 measurements system with the help of a sensor from AlphaSense and the LMP91051 AFE from TI. The schematics for my prototype are exactly the same proposed in the application notes.
Last week I was able to finally record my first waveforms and it seems the voltage delta between the detector and the reference seems a bit small. On the left is what I got, on the right is the screenshot from the application notes:
![]()
![]()
In the application notes the delta is about 30% of the whole RC step response magnitude, in my plot I would say it is about 15%, I also read that two measurements were made, one at 130ppm and the other one at 5000ppm. On the right, is the delta higher because the CO2 concentration was 130ppm? My measurements were made in "open air" so I assume it would explain theses differences, given the average CO2 concentration of 400ppm in the atmosphere, I just wanted to make sure.
Any help or confirmation on that would be much appreciated.