Some weeks ago I ask about a problem I had configuring a AD9835 (AD9835 FSYNC voltage level). Acording to the answers received it seemed that my chip was malfunctioning.
I bought some other chips and tried again, but the problem still existed. The chips didn't even output 1.21V at the reference node. I decided then to make a very simple design to test my chips. And here is where my questions arise.
- Is it really necessary to use uncoupled or separate sources for AVDD and DVDD or it is only recomended in order to acheive a better response? Can the chip function if I connect AVDD and DVDD to the same 5V source?
- In order to see the 1.21V output at the refout pin, what would the most basic circuit be? Can I simply power the AVDD node?
Thanks for your attention