Other Parts Discussed in Thread: TSW1418EVM, ADC3683
I've been testing the ADC on a ADC3683EVM that is connected to a TSW1418EVM for data capture. There are many harmonics and spurs generated compared to what is shown in the ADC366xEVM Evaluation Module User's Guide. The spurs have been observed in 2W configurations 16/18 bit for both bypass and complex modes. I followed the procedure described in the User's Guide to configure the ADC3683EVM in Bypass mode (2W) with various frequencies attempted for FCLK and DCLKIN=4*FCLK. Power levels matched values of FCLK and DCLKIN suggested in the datasheet and were adjusted to lower values independently and together without improvement in the spectrum. I also added appropriate filters as described in the User's Guide without improvement. Without an input signal the noise floor doesn't have any spurs. Results are similar for signals only in channel A or B and in both together. I used multiple sources for the clocks and the signal generation with the same results. Any recommendations? Thanks!
My Capture:
User's Manual:
