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ADS42LB69: RF sub sampling

SM
Expert 1760 points
Part Number: ADS42LB69


Hello,

      We intend to use the ADS42LB69 in RF sub sampling where the frequency of interest is going to be in the 4th Nyquist zone when the ADC will be sampled at 250MSps. 

Two questions here:

1) Do you anticipate any issues here? 

2) What will be the best way to drive the ADC (transformer/balun or opamp/adc driver). The input is going to be pulsed. Will an opamp help when the input is pulsed?

3) If an opamp is a better way to drive the ADC then please advise the part number and circuit.

Regards,
SM. 

  • 0
    TI__Guru* 91947 points

    SM,

    You will need a filter to remove the images that will be present in the 4rth Nyquist zone. Attached is a FFT plot with a 450MHz input tone with the ADC sampling at 250MHz. The tone was filtered with a 450MHz BPF.

    You will probably need an amplifier as the filter will attenuate the input. I would post your question to the high speed amplifier forum to get their advise regarding an amplifier option.

    Regards,

    Jim

    450MHz IF, 250MHz clock, CHA.pptx