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TLV320AIC3100: DAC output voltage at full scale

Yuta Nishie
Genius 4135 points
Part Number: TLV320AIC3100

Tool/software:

Hi,

If Page 0/Register 65 [D7: D0] (DAC Left Volume Control) and Page 0/Register 66 [D7: D0] (DAC Right Volume Control) are set to 0000 0000, how many volts is the DAC output at full scale?

Best Regards,

Nishie

  • +1
    TI__Expert 6730 points

    Hi Nishie,

    This volume control register set the digital gain of the signal. So, at 0dB gain, the full-scale signal will output at the full scale output on the DAC, which should be 0dBFS digitally in the DAC. The output voltage depends on which output you are using, this device has a headphone/line driver as well as a class D amplifier. The headphone/line driver output voltage should be corresponding to HPVDD, which might be 3.3V for example, so the voltage peak-to-peak of the signal out would be 3.3V. From the amplifier output, the voltages are approximated in the datasheet. Since the amplifier has a different gain stage after the digital gain, your output voltage will vary. In the datasheet example, they had a 0dBFS input signal and a 6dB gain on the class D amp, and 3.6V SPKVDD, which gave a 2.2Vrms output with 1.8V common mode. It seems to me that the signal is centered around half of the SPKVDD with a little less than a 3.6V output swing due to the inefficiency of the amplifier.

    Let me know if you need more help with this!

    Best,
    Mir