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ADC32J25: analog input BW

Victor Levy
Intellectual 2316 points
Part Number: ADC32J25

Hello,

I have a customer who is asking a question regarding a spec for this device,

he is asking how did we get the 450 analog input BW.

he doesnt understand since the sample rate (max) is 160.

  • 0
    TI__Mastermind 20130 points

    Hi Victor,

    The analog input BW needs to be more than the sample rate, to accurately resolve the sample to 12 bits for this specific ADC.

    As the resolution of the converter changes, gets higher, the required BW also increases in order to resolve samples accurately at that specific resolution.

    Regards,

    Rob

  • 0 in reply to Rob Reeder
    TI__Intellectual 2316 points

    Thank you Rob, 

    I sent this to the customer and his question was how is the input 900MHz analog BW while max sample rate is 160MHz,

    He assumes this at under sampling, is that correct?

  • 0 in reply to Victor Levy
    TI__Mastermind 20130 points

    Hi Victor,

    This is true for under sampling, but also true for sampling within baseband or 1st Nyquist as well.

    Though if a converter was designed for only sampling with 1st Nyquist the BW of the ADC would have to be higher than the sampling rate, but maybe not as high as the example above.

    Hopefully that helps.

    Regards,

    Rob

  • 0 in reply to Rob Reeder
    TI__Intellectual 2316 points

    Hello Rob, 

    I explained this to the customer(RF engineer) - however he doesn't understand the way this works, 

    If the sample rate has to be at least twice the bandwidth, how is the sample rate at 160?

    Is it split between two DACs? ( I and Q) and then it's 4 times the sampling rate in actuality?

    Let me know if you would like me to CC you with the customers question so you can answer directly.

    Thanks,

    Victor Levy

     

  • 0 in reply to Victor Levy
    TI__Mastermind 20130 points

    Hi Victor,

    Yes, I think an email would be best and the product the customer is looking at.

    I can keep you on copy.

    Regards,

    Rob