Warren,
This behavior is not expected from the device. I have a few more debug questions.
- Is the oscillation happening at the input of the OPA4277 or at the output?
- Can you verify that your reference does not have a ripple?Also could you verify the values of the registers that you are using?
- The datasheet for the REF5025 recommends a 1-10uF input capacitor and a 1-50uF output capacitor.
This information will help me evaluate the issue more accurately.