Just to help clarify things for me, I’m designing a circuit for a general purpose daq application (goal being lowest achievable noise from ~1ksps to ~64ksps) with the ad7768-1, ada4254, and TBD external reference. Looking at the datasheet for the amplifier, it says that it can be connected directly to the ad7768-1 however it’s 3db bandwidth is significantly lower than the input switching frequency of the AD converter. When selecting an external voltage reference, as well as the input amplifier, should I be looking at their output impedance at 2*fmod when determining the error budget? I’m trying to determine if buffers are actually required. For a second question, the datasheet section for the ad7768-1 VCM output mentions requiring a low pass filter. Should the target bandwidth be equal to the ODR Nyquist frequency? Is this bandwidth for responding to the VREF current switching transients?
