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ADC12D1800 SFDR Improvement

we are using ADC12D1800CIUT/NOPB; non RF part in one of the boards and are facing SFDR issue with the Fs/2 spur component in the captured data. Fs/2 component is prominent at -58dBm on all the boards. We have previous version boards which are using RF part and giving the better SFDR (better than 62dBFS). I want to understand what could be the possible reasons for this problem. Please help!

We are capturing the 160MHz input signal at 500MSPS and spike is seen at 250MHz which is Fs/2. Attached the capture of the ADC with no signal input.

  • Hi Abdul,

    Can you please confirm that you have been performing calibration on the ADC after it warms up? Calibration helps to achieve the full rated performance and maximize SFDR. Do you see any improvements in SFDR after the calibration is performed?

    Coupling from the data clock (DCLK) into the output can also contribute to fixed frequency spur. In 1:2 Demux mode the output data is updating at half the sampling frequency. If possible, try using the NON-Demux mode and see if it impacts the Fs/2 spur.

    Also I can’t find the ADC capture that you mentioned. You should be able to add the attachment by first clicking on the “Use rich formatting” link below the reply box, and then using the Insert/Edit Media or Insert File tools above the reply box.

    Regards,
    Neeraj Gill