Hi,
We are at the late stages of a design using the ADS1263 32-bit A/D converter. We need to get our product to the field but are stuck on a noise issue.
We have both the ADS126XEVM Evaluation Board and three custom prototypes. Everything is working fine except for our noise is very high compare to what the datasheets say it should be.
Both the Evaluation Board and our prototypes have 20uV of noise that we cannot get rid of it. We have spent close to two weeks on this issue and are totally out of ideas so hopefully someone can help. If it was just our prototypes I would keep looking, but we are stumped how we can’t even get the ADS126x Evaluation Board to meet specifications either.
According to the ADS1263 datasheet and other documentation like the TIDUAC1 reference design we should be able to get noise <1uV and both our design and the evaluation board are 20uV noise.
Here is our setup:
- We are trying to measure temperature with 0.000X Celsius precision. Right now we are 0.00X with our 20uV noise.
- We are using the 4 wire configuration as in page15 of the ADS126xEVM data sheet.
- 1k ohm Platinum RTD
- 1k Precision reference resistor.
- ADC Pro is setup to match the configuration and it measures properly (not consider the noise floor). We are not using any gain.
We have tried everything from a Faraday Cage, every option in the software, different reference values, different RTD values, shorting the inputs together, etc. Always 20uV noise on both the Evaluation board and our prototype.
Any help would be appreciated since we are not sure what to do at this point.
Thanks,
Aaron