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TLV320AIC3106: White noise output levels

Part Number: TLV320AIC3106

Hello,

Working on a project that is using the TLV320AIC3106.  I am running into the issue of white noise (hiss) on the RIGHT_LOP/M outputs (and others).  When the software turns on the output, I'm seeing around 300mVp-p on each leg.  Obviously when using a differential 3w audio amplifier (with a gain of 10) on the output, the noise is very noticeable.  Are there any design guidelines what we might be missing that would help in this area?  (i.e. LC filters on the power supplies).  We are currently using a 10 layer board with stacked power/ground layers.  DC power supply decoupling caps are placed as near as possible to their power pins (1.8V, 3.3V, & 3.3V_Audio).  Digital and Analog ground tied together (via a 0 ohm resistor) on the bottom layer (opposite of the IC).  We have yet adjusted any of the Noise Gates.

Any info would be greatly appreciated.

Thanks,

Randy Nelson

  • Hello Randy,

    If you can provide a schematic and register dump, I will gladly take a look. This sounds to me like Out of Band noise and a simple way to solve this is to add a low pass filter with a ~30kHz cutoff on the outputs of the codec. 

    Regards,

    Aaron