I have a customer using the AD9783. They do not require all of the DAC input bits, but already use this device in other places. See questions below:
"I don’t see mention of a “fail safe” mechanism for floating / open (i.e. unused) inputs in the data sheet, and there does not appear to be any which is part of the evaluation board circuits.
Is it advisable to tie these bits off in a resistor/divider circuit to bring them to a known state? Or is some fail safe mechanism in place, but not mentioned?"