I am using AD5445 to generate output voltage 0-1.25V from a single 5V supply.
I literally implemented circuit from the figure 51.
Vin is supplied from ADR391 (2.5V voltage reference), the bias voltage is exactly 1/2 of the Vref.
My output buffer is designed with LTC6078.
I expected to have 1.25V on the output if the code written into dac is 0x0000, and I expect to have 0V if 0x0FFF is written into the DAC.
If nothing is written I expect to have 1.25V. I am able to read what I wrote into DAC.
The problem is that I always have 11mV on the output of the circuitry.
I checked CCA few times, all voltages are at the correct level,
The design is done correctly on 6 layers board and assembled and tested by the board house.
Is the problem caused with my usage of LTC6078? Should I switch to AD8066 since the package is the same?