Part Number:ADS124S08EVM
Hi,
I am testing the ADS124S08 using the eval board to confirm that the ADC can be used for precise voltage measurements (on the order of microvolts). I have been using strain gauges in a full Wheatstone bridge configuration connected to the EVM. This circuit should not change its output with temperature, which I was testing to confirm. Using a Thermotron, I was testing the ADC for drift with temperature, but noticed that the output voltage seems to be drifting over time, regardless of temperature, about 20-30 microvolts over an hour and a half.
Is there a reason I am seeing this drift from the ADC? Based on the datasheet for the ADC, I was not expecting this drift over time.
Between each sample, the ADC is not powered. Before taking a sample, I plug in the EVM, run the "Bridge Measurement using J8 and REFP0", set the gain to 4, use the Sinc3 filter, and set the data rate to 50 sps. I then take data for 75 seconds. I have attached some graphs of data where you can see the voltage drift below. Usually, it drifts up, but in one case it drifted down. I also tried switching to using global chop instead of the ADC calibration, but still saw a downward drift over time.
Thank you for the help!
