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PCM2903C -- Possible to digitize DC

mmu
Prodigy 170 points

I'm in an rather unusual measurement situation, where both audio signals of a 10kHz bandwidth and a rather slowly changing voltage value are of importance:

Would a DC signal supplied to the audio input channels (of course not using the input capacitors) be sensed, and digitized correctly via USB?

If so, would simply biasing it around 0.5* Vccc, with a peak-to-peak voltage of 0.6 * Vccc suffice?

Also, I haven't been able to find crosstalk attenuation over frequency; am I just missing something?

Best regards,

Marcus Müller

  • 0
    TI__Guru**** 189399 points
    Hi, Marcus,

    Unfortunately, being an audio device, this was not designed for, characterized for, or intended for dc applications.

    We did not publish cross-talk performance for this device.

    -d2
  • 0 in reply to Don Dapkus
    Prodigy 170 points

    Dear Don,

    sadly, that was the reply I was expecting, yet hoping to be proven wrong.

    Given the input impedance of "only" 30kΩ (which might be driven by what is effectively a constant voltage source of up to (0.5+0.3)*Vccc), is it likely that I damage the analog input circuitry by driving it with a constant voltage?

    Also,

    We did not publish cross-talk performance for this device.

    kind of implies you have an unpublished expectation how your devices might perform. Give or take 16dB, what would you assume to be crosstalk at 0.3 * fs - 0.5 * fs? (I'm usually in the business of RF electronics, so I'm not really expecting you to be able at all to tell the analog characteristics of integration-centric devices by the 10th of a dB; for us, analog is where things are rather good when they are within 10dB of expectation...)