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TLV320ADC3101EVM-K: ADC3101 EVK Problem on Right Channel

Roy Chou1
Genius 12635 points
Part Number: TLV320ADC3101EVM-K

Team,

We are analyzing the noise floor on ADC3101.

On ADC3101 EVK, we found that there is a peak on the right channel as the figure down below. The frequency of the peak increases with the analog gain.

Left channel doesn’t have this kind of problem.

Do you have any suggestion for this problem?

Roy

  • 0
    TI__Genius 12635 points

    Team,

    Any comments?

    Roy

  • 0 in reply to Roy Chou1
    TI__Mastermind 23050 points

    Hi Roy,

    I will have to dig into this myself to confirm, but assuming this is not coming from your input source, I suspect this is a small idle tone on that channel. It is not uncommon to see small idle tones around the noise floor on some channels. This can happen based on your configuration of the inputs and possible parasitic pathways between other sections of the device. The tones are generally low enough level to go unnoticed in any actual application. A microphone for example is going to have a noise floor much higher than the peak of these tones. The SNR of ADC3101 is specified as -90dB typical, so I'm assuming that you are seeing a much lower noise floor by averaging FFTs as your traces look very clean. At that point the idle tones become apparent, but typically these will not be noticeable above the noise floor of the IC. 

    In short, this should not actually be a problem in a real application!

    Best,

    Zak