What input resistance for AD7960?

I would like to know what would be the maximum recommended resistances to place between an FDA and AD7960 inputs (R3 and R6 on the figure below). I would like to reduce the capacitor value to reduce power consumption of the LTC6363 and increase the resistances accordingly to keep cutoff frequency. I am thinking of 200R or 300R instead of 100R. The input signal is a amplitude modulated sine wave, 125kHz.

Thank you in advance for your inputs.

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  • Hello, Jonathan, thank you.

    As a complement to the info above, I do not need absolute accuracy in terms of A/D conversion. I may live with small errors due to input bias current or bias due to AD7960 S/H capacitance. My main concern is the higher resistances degrade SNR too much or add too much error or some other thing I may be missing.

    Regards.

Reply
  • Hello, Jonathan, thank you.

    As a complement to the info above, I do not need absolute accuracy in terms of A/D conversion. I may live with small errors due to input bias current or bias due to AD7960 S/H capacitance. My main concern is the higher resistances degrade SNR too much or add too much error or some other thing I may be missing.

    Regards.

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