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TLV320AIC34 single ended input signal ranges

Christopher Ingraham
Intellectual 1000 points
Other Parts Discussed in Thread: TLV320AIC34

We're using the TLV320AIC34 codec in single ended input mode.  The datasheet specifies the absolute maximum rating for single ended inputs to be 0.707Vrms.  What I'm trying to figure out is what the full scale voltage range is for the input and what this range would correspond to in values read from the Codec.  My assumption is the voltage input signal can go from 0v to 2v where 0v would correspond to a 16bit reading of 0x0000 and 2v would be 0x7FFF.  Please let me know if this is correct.  If not, what is the actual voltage input range and corresponding readings?

  • 0
    TI__Guru* 84915 points

    Hi Christopher,

    The voltage input signal can go from 0V to DRVDD (ADC analog supply). So, in a 16 bit reading, 0V would correspond to 0x0000 and DRVDD to 0x7FFF.

    As datasheet mentions, 0.707 Vrms is a recommended operation condition for single ended input. I suggest not to work over this value, even if the signal is between 0V and DRVDD.

    I hope this helps you. If you still have questions, please let me know.

    Best regards,

    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Intellectual 1000 points
    Hello,

    So just to be clear here. If I were to input a pure sine wave into the single ended input, the sine wave should be limited to a peak to peak voltage of 0 to 2v which would result in the 0.707Vrms. Even if my DRVDD analog supply was 3.3v, I should limit my input to 2v max. (for the sine wave). Is this correct?

    Further, this would imply that the real 16bit readings would correspond to something more like 0 to 0x4D92 if my DRVDD was 3.3v. I calculated this value assuming 7FFF would be 3.3v, so value of 2v would yield (0x7FFF * 2v) / 3.3v = 0x4D92.

    Thanks for you help so far!

    Best regards,
    Chris
  • 0 in reply to Christopher Ingraham
    TI__Guru* 84915 points

    Hi Christopher,

    Yes, that's correct. The analog input voltage can go from 0 to DRVDD analog supply (3.3V in this case), but in typical applications you need to limit the analog full-scale 0dB input voltage to 0.707 Vrms as datasheet mentions in Recommended Operating Conditions section. So, I recommend to work with datasheet specifications.

    I hope this helps you. If you still have questions about the input signal ranges, please let me know.

    Best regards,

    Luis Fernando Rodríguez S.