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Original question:

PCM1808: Poor frequency response with voltage divider on analog inputs.

PCM1808: Input Impedance

Shunsuke Nagata
Genius 13190 points
Part Number: PCM1808


Hi,

PCM1808 datasheet shows that Input impedance is 60k ohms but the impedance of average of 6 device is 37.9k ohms. My customer's schematic would be affected the validation of input impedance.

So, could you please let me know the Max / Min value?

Regards,
Nagata.

  • 0
    TI__Mastermind 23050 points

    Hi Nagata,

    This isn't something we characterize for a max/min value, but it can vary quite a bit with process and with modulator frequency. My recommendation would be for the customer to design their circuit in such a way that does not rely heavily on the value of the input impedance. In general, it is best to drive data converters with low impedance sources and a buffer between their previous stage and the PCM1808 should solve any issues they are having.

    Best,

    Zak