Great Noise Problem in AIC3100

Liang-Bi Chen

There is a great noise problem when turning on Class-D function (Register setting is P1/R32, D7=1).

We taken some experiments/Settings which are described as follows.

1. When we set to use DAC, thus, both HP output and Speaker have great NOISE.

2. When we set to Speaker source from the MIC1LP input, thus Speaker is NO noise, But HPR still has Noise (source from DAC_R).

How to solve above problem?

over 12 years ago

0 Dominik Hartl11 over 12 years ago

TI__Guru 64266 points

What's the spectrum of the noise? The DAC3100 will produce noise above the audio band. This is inherent to the delta-sigma architecture. You can solve this with a first order RC low-pass filter on the output with a fc of approx. 25kHz.

0 Liang-Bi Chen over 12 years ago in reply to Dominik Hartl11

Prodigy 180 points

Dear Sir,

We have not solved the noise problem mentioned above.

Could you provide me a recommended/reference circuit to solve such problem?

Our problem is described as follows.

1. HP_L will be generated the noise when Class-D is power on.

0 Dominik Hartl11 over 12 years ago in reply to Liang-Bi Chen

TI__Guru 64266 points

Do you observe this noise on the TI EVM? Please quantify the noise.

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Great Noise Problem in AIC3100