TLV320AIC3104-Q1: GSM TDMA Noise - Ferrite Beads on the MIC lines

Pradeep Mohan

Part Number: TLV320AIC3104-Q1

Hello TI,

We have an issue with TDMA noise on our microphone signal lines. Considering the layout cannot be optimized due to time constraints, we have considered using a ferrite bead on the MICP and MICN lines.

I have selected one of the ferrite beads from TDK designed specially for audio signals against TDMA noise, to be more specific this one.

Datasheet here.

Would it be acceptable to insert the ferrite beads in series just before the dc blocking capacitors C156 and C157?

over 6 years ago

0 Steve-Wilson over 6 years ago

TI__Mastermind 30220 points

Pradeeep,

yes, this is ok. You can use some small value caps across the input if you want too. (value dependent on your needs)

best regards,
-steve Wilson

0 Pradeep Mohan over 6 years ago in reply to Steve-Wilson

Intellectual 725 points

Hello Steve!

thank you for the quick response. I was wondering if having the ferrite beads and the ac coupling caps in series would be a problem, any suggestions? Small value caps across the two inputs or to ground?

Thank you again!

0 Steve-Wilson over 6 years ago in reply to Pradeep Mohan

TI__Mastermind 30220 points

Pradeep,

The Ferrite beads shouldn't cause any problems. regarding the caps, either way works, I'd recommend putting footprints for both and testing to see what resolves the issue best.

-Steve

Audio

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TLV320AIC3104-Q1: GSM TDMA Noise - Ferrite Beads on the MIC lines