CM403 Voltage Reference ADC0

Hello everyone,

I make my first steps with  the CM403-Evalkit and for beginning I tried the ADC-Examples. I observed a similar effect as Vijay explained. I used the ADCC-Linear example-Project and inject sinusoidal signals. At the channels of ADC0 I saw flipping signals, even in the case of very small amplitudes (Picture 1: 50mV AC and an offset of 400mV). Changing to external voltage reference had no effect.  

If I connect a sinus-signal (offset 0.5V amp 0.5V)  to Channels of ADC1 with the same configuration parameters, I see the expected signal in the sampling buffer.

Does anyone have an idea? 

Thanks

-Slaender