PCM2912A: Pleaes review: replacing the 3.5mm TRS Jack with an Electret Microphone

Mo Mizzi

Part Number: PCM2912A

Tool/software:

Just wanted to see if the following connection (green box) looks alright. We have used the PCM2912A with a 3.5mm Jack in the past. It worked great for us back then.

However, we have a need to put an onboard Electret microphone instead. Can you please review the schematic below (specifically the green box) and see if anything stands out to you.

For testing purposes, I have connected the MicBias (MBIAS) and MicOutput (VIN) through a three way jumper. That I can feed into the +ve lead of the microphone.

7 months ago

+1 Mir Jeffres 7 months ago

TI__Genius 12965 points

Hi,

Yes, this looks fine for an electret microphone system. Make sure your MICBIAS is around 3V or higher for ideal operation of the microphone according to its datasheet.

Let us know if you have any more questions!

Best,
Mir

0 Mo Mizzi 7 months ago in reply to Mir Jeffres

Intellectual 290 points

Hi Mir,

Thank you for quickly reviewing this and clarifying it for me.

I'm not sure how to ensure MICBIAS is 3.3V or higher? Below is the audio portion of the PCM2912A. It is being powered by 5V.

0 Mir Jeffres 7 months ago in reply to Mo Mizzi

TI__Genius 12965 points

Hi,

MICBIAS is .75*VCCA for this device, so if your VCCA is 5V, then the mic bias will be 5*0.75 = 3.75V. That will work just fine for the mic.

-Mir

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PCM2912A: Pleaes review: replacing the 3.5mm TRS Jack with an Electret Microphone