We are evaluating the noise performance of the AD5292 using the Analog evaluation board (EVAL-AD5292EBZ).
We can measure the noise spectra for different resistance values and it matches the noise floor specifications, basically limited by Johnson noise. However, there are a few spectral peaks (at about 20, 30, 40 Hz) that appear on the measurements only when using the AD5292 resistance (we do not see these peaks using a normal analog resistance). We have tried to supply the board with external voltages, even using batteries to reduce any external source of noise.
Has anyone also seen these peaks when using this evaluation board? I would like to know whether the peaks are originated in the board itself, or if it is something coming from the AD5292 chip. This way we can assess whether the chip is suitable for our application or not.
Thanks a lot!