Something about Digital to Analog Converter

[cyw1984]

I am used a AD5678 -2 (16 bit

 

[oladiladio1]

I guess you will have to live with that. When you take a closer look at the specs (page 3) you will see that the zero-code error is between 1mV and 9mV.

 

[MP1]

You never have to live with the wrong output when you are designing the circuit yourself. First, you should check to see if this is just circuit noise. Did you use bypass capacitors and all recommendations to keep noise out of the circuit? What do you get when you test other voltages as well? If you have this same offset throughout the entire range, you can run the output through an op-amp and compensate for the offset with the op-amp.
Otherwise, you can add a bias circuit which adjusts zero and span both. This will require an additional op-amp.

MP