I am very concerned with low frequency noise in Sigma DSP processors. I have tried two different eval boards, the latest one is EVAL 1701. I am measuring 1/f noise that is several microvolts/rtHz (@10 Hz) . I am wondering if you can tell me if this noise is somehow intrinsic to the DAC or is it the ADP3336 voltage reference. The noise from the voltage reference seems to be approximately in the same range.
BTW, what sets the electronic noise floor of the ADCs (couldn't quite follow internal function of the ADC_Res pin)? Is there something that I can do to clean up some of the very low frequency noise?