In Your data sheet for the AD7856ARS page 7. Pin 7 CREF1, it says 470n NP0. Is
We cant find such high value with NP0.
The recommendation that the 470nF capacitor be an NPO type is not really
required in practice. We have achieved specified performance without an NPO
capacitor in place. The reason for the dual decoupling capacitors is to
effectively decouple the high frequency bursts of charge which arise in the
DAC. So the absolute value of the capacitor is not so important. Any 470nF
ceramic capacitor with low ESR, ESL is suitable. The designation of a capacitor
as NPO means that it's value does not have a significant positive or negative
temperature coefficient. We originally thought that the high equivalent series
resistance of high value ceramic capacitors could cause a problem but this
turned out not to be the case.