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PCM1809: Audio ADC and MEMS Microphone selection recommendation

Sal Ye
Mastermind 25435 points
Part Number: PCM1809


Tool/software:

Hi team,

I am working on the new TI LaunchPad design which will support vocie detection function. So I am looking for a audio ADC for the signal detection. Then I find our Audio device (PCM1809) which could meet the requirements.

I also find the PCM1809EVM has integrated the microphone in the board.

Could you give some advice for the Audio ADC device and the microphone device recommendation?

It is much helpful if you can help define the audio device part number on my launchpad. Meanwhile, please let me know any tips I should take care of if I want to integrate the function within the board.

B.R.

Sal

  • +1
    TI__Mastermind 48205 points

    Hi Sal,

    It will be hard for me to pick the perfect microphone for your use case. But here are the important factors to consider:

    Sensitivity - This is defined as the dBV output from the microphone when a given test signal is played. According to the microphone you shared, it has a sensitivity of -37.5dBV when exposed to 94dB SPL. Consider how much voltage you want your ADC to receive as the microphone records signals, and choose an appropriate sensitivity. Keep in mind that microphone outputs are always quite small (in the order of 10s of millivolts rms).

    Bandwidth - Since you're doing voice you will likely want the full audio bandwidth. 20Hz to 20kHz or close to it. A high quality voice typically resides in the 200Hz - 8kHz band.

    Power Requirement - Pretty straightforward, make sure the voltage required to bias/power the microphone is available in your system.

    Directionality - SMD mics like this are most likely going to be omnidirectional, but consider if you want your microphone to pick up sound from all directions, or only a certain direction, such as directly in front of the mic but not behind it.

    This is a microphone that we use on some newer EVM designs that might perform better than the one on the PCM1809, which is an older design: https://invensense.tdk.com/products/analog/ics-40720/

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    TI__Mastermind 25435 points

    Hi Jeff,

    Much appreciate for your suggestion here, it is helpful.

    A further question here, could you share the partnumber of the newer EVM to me, I could double check the user guide for my reference.

    Jeff McPherson said:
    This is a microphone that we use on some newer EVM designs that might perform better than the one on the PCM1809, which is an older design: https://invensense.tdk.com/products/analog/ics-40720/

    B.R.

    Sal

  • +1 in reply to Sal Ye
    TI__Mastermind 48205 points

    Hi Sal,

    It is the ADCx140EVM: https://www.ti.com/tool/ADC3140EVM-PDK

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    TI__Mastermind 25435 points

    Hi Jeff,

    Thanks for your support here.

    B.R.

    Sal