TLV320AIC3111: Output of the codec is not satisfactory

Souvik Saha

Intellectual 625 points

Part Number: TLV320AIC3111

Hello all.

I'm using the TLV320AIC3111 audio codec for audio signal processing and filtering.

My setup -

AGND is given to MIC1LP acting as input

Expected O/P -

Flat DC signal over SPLP and SPLM ports

Actual O/P -

As attached in the image file

I'm obtaining this 450mV noise signal which has a frequency of approximately 300kHz.

Any quick workarounds for this ?

over 4 years ago

0 Steve-Wilson over 4 years ago

TI__Mastermind 30090 points

Souvik,

This would be out of band noise. You can use a LPF as described in the application report below:

This is really only necessary for applications where you sending the output to a Class D amp, for most situations the noise is irrelevant and cannot be heard.

best regards,

-Steve Wilson

0 Souvik Saha over 4 years ago in reply to Steve-Wilson

Intellectual 625 points

Thanks for your response.

Will this affect i2s output?

0 Steve-Wilson over 4 years ago in reply to Souvik Saha

TI__Mastermind 30090 points

Souvik,

I'm not sure what you mean. This LPF goes on the Analog outputs.

best regards,

-Steve Wilson

0 Souvik Saha over 4 years ago in reply to Steve-Wilson

Intellectual 625 points

I meant will this noise also be present in the i2s output?

0 Steve-Wilson over 4 years ago in reply to Souvik Saha

TI__Mastermind 30090 points

Souvik,

The ADC does have some anti-aliasing filters built into the input buffer and PGA. so you wouldn't see the noise getting folded back if you sent the DAC directly to the ADC... is that what you're asking?

best regards,

-Steve wilson

0 Souvik Saha over 4 years ago in reply to Steve-Wilson

Intellectual 625 points

A simple RC filter with cutoff of around 20kHz did the trick.

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TLV320AIC3111: Output of the codec is not satisfactory