On your new board where you've worked hard to keep the noise low, what do you get for the ADuCM350's noise-free resolution (there's no such spec listed in the datasheet). That is, for 160,000 samples/sec what is the effective number of bits (or noise-free resolution)? I'm getting about 12 bits, see attached, when I do the measurement for ADC offset (VBIAS against VBIAS). At 900 SPS, there's zero noise, but at 160,000 SPS, I get ~20 counts peak to peak noise. Is
this what you see?