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ADS8319: ENOB vs. Sampling Rate

Ue
Genius 17165 points
Part Number: ADS8319

Hi all

My customer is using the ADS8319 at 30ksps and he has this quesiton:

On page 11 of the Datasheet there are ENOB-plots vs. various parameters, all given at fs=500ksps.

Do these numbers change when going to 30ksps ?

And if yes: Do you have plots or specs for ENOB at lower sampling rates ?

Best regards

Ueli

  • 0
    TI__Mastermind 46310 points

    Hello Ueli,

    These numbers should not change when using the same external amplifier and reference.  If you short the inputs and take several readings, the rms noise and peak-peak should be nearly identical at 30ksps or 500ksps.

    Running at a lower sample rate does reduce the requirements on the input amplifier and the reference buffer.  If these are not designed correctly, performance at 500ksps will suffer, but running at 30ksps you will get much closer to datasheet performance.  Also, if you are running at 30ksps, you can probably use a lower cutoff frequency input filter, which will reduce external noise that could get into the readings.  From a system perspective, you could get better overall performance, but this will not be due to the ADC.

    I will take a look at this tomorrow on an evaluation board using a similar ADC to confirm.  In either case, I do not believe we have any additional data other than what is already in the datasheet.

    Regards,
    Keith Nicholas
    Precision ADC Applications

  • 0 in reply to Keith Nicholas
    TI__Genius 17165 points

    Hello Keith

    Thank you for the quick reply and the detailed explanation / clarification.

    For the time being that is fine and no further action from your side required.

    Best regards

    Ueli