PCM5100: Input Overload Level?

Hello Jay, input overload occurs when the input signal level is too high  and as the name implies,  it overload the  amplifier stage and cause clipping . 

This is a DAC with digital input,   at most your input is  a stream of all ONEs such as  111..111 .  Using its internal reference , the DAC generates its full scale voltage  ( here is 2.1Vrms) . Unless I am missing something in their question, I don't think it applies here.

Regards,

Arash