In my research project i used AD7328 ADC in order to readout unipolar analog signals.
SPI digital communication was isolated by using ADUM3481.
During prototyping i noticed that digital isolator was broken. After a long search period i found my mistake that "VSS" pin of ADC was floating, instead of direct ground connection, as given in the below schematic picture.
but i could not understand why digital isolator was failed instead of ADC? In AD7328 datasheet i could not see any detailed internal structure to tie up this failure to my mistake.
Could you pls explain me how my mistake could reason digital isolator failure?