Hi, I'm using the AD9286 in a new design and I have a little question about the Vref.
I want to use the SPI comunication to control the Vref. But do you need to put 1V on this pin or the pin need to be NC.
If you are planning to use the internal Vref, then allow the pin to float. This will allow you to adjust the Vref via SPI.
When using an external Vref, then apply the voltage to the pin.When doing so, the SPI is not used to control the Vref.
Fromt he Datasheet:
An internal differential voltage reference creates positive and negative reference voltages that define the 1.2 V p-p fixed span of the ADC core. This internal voltage reference can be adjusted by means of SPI control. It can also be driven externally with an off-chip stable reference. See the Memory Map Register Descriptions section for more details.