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ADS7028: Maximum input frequency

AhmadBashar Taji
Prodigy 50 points
Part Number: ADS7028

Tool/software:

Hello,

I want to use ADS7028 to measure the RMS value and generate ZCD for an AC signal with a frequency of 50kHz.

Can ADS7028 handle 50kHz? and what is the maximum input frequency?

With best regards

  • 0
    TI__Genius 15510 points

    Hi AhmadBashar,

    Theoretically there is not a maximum input frequency, as at 1MSPS, the Nyquist frequency is <500kHz, but you can compute the true RMS of a higher than Nyquist frequency so long as the sampling rate and input signal are not co-periodic and the observation window is long enough.

    One concern will be the low-pass filter effect as a result of the RC input of the device and other front end components. The ADC driver circuit will also have to be carefully considered to permit sufficient settling time for a 50kHz signal. 

    Regards,
    Joel  

  • 0 in reply to Joel Meraz
    Prodigy 50 points

    Can you provide guideline for designing the ADC driver circuit and other front end components to support 50kHz signal?

  • +1 in reply to AhmadBashar Taji
    TI__Genius 15510 points

    Hi AhmadBashar,

    For this, I suggest referencing our TI Precision Labs videos, specifically the SAR ADC input driver design videos. I've linked the first video below. They provide comprehensive guidance to designing the front end ADC circuit. Feel free to follow up with any questions that might arise.

    https://www.ti.com/video/5476574757001

    Regards,
    Joel