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AFE7950: Sampling Rate

Kazuto Odajima
Prodigy 225 points
Part Number: AFE7950

Tool/software:

I have a question about the sampling rate of the AFE7950.

Are the combinations of sampling rate and interpolation/decimation only those in the following table in the datasheet?

(Table 8-5. RX Decimation Rates

Table 8-6. Interpolation Factors Between Input and DAC Sample Rates

Table 8-7. Decimation Factors Between FB ADC and Output Sample Rates)

For example, I was thinking of inputting a 2500MHz clock to the AFE, but looking at Table 8-6, the DAC SAMPLE RATE is 4500MSPS to 12000MSPS.

If I input a 2500MHz clock, do I need to increase the frequency to 5000MHz using the internal PLL to match Table 8-6?

  • 0
    TI__Expert 5035 points

    Hi Kazuto,

    The combinations of sampling rate and interpolation/decimation shown in the table can be scaled down. For example, looking at table 8-5, if I want the ADC Fs = 2300 I could use either of the decimation factors from the 2500 and 3000 columns since I am scaling the rates down. But I would not be able to use any decimation factor that is not in those two columns. This is the same for the DAC channels.

    Other limitations are that the minimum output rate is 61.44MHz for the ADC channels and 122.88MHz for the DAC channels.

    For this case we recommend setting the DAC Fs to 5GHz.

    Best,

    Camilo