I need help. I am a student. I am runing out of the time with my project. I am using the AD7685 converter and I am having a problem with it. I tried a CS with and withiout busy indicator mode and other modes but, I see the same problem. I am using 5V VDD and 2.5V Vref decoupled throught 10uF capacitor. When the input voltage is over 0.5V the 4 LSB bits are constantly 1111 . However, the rest of bits seems correct. What can be a problem?