• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 102 subscribers
  • Views 1098 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMDSLCDK6748: Audio in/out using MEMS mic/speaker

Beki
Prodigy 20 points
Part Number: TMDSLCDK6748
Other Parts Discussed in Thread: TLV320AIC3106, TPA2012D2, LM48580, TPS61046

Hello everyone,

So far I managed audio in/out using a microphone and a headphone in c6748 LCDK. However, for the project I am working on, I need a small mic/speaker (MEMS). Since there is no built-in amplifier in the LCDK, do I have to have an external amp for MEMS speaker? If yes is there any amplifier from TI that supports MEMS speakers? And is there any way to wire mic/speaker into LCDK except 3.5mm audio jack LINE IN/OUT?

Any help will be appreciated. Thank you. 

  • 0
    TI__Mastermind 29570 points
    Hi Beki,

    What MEMS mic are you thinking of using? MEMS microphones can behave like traditional electret analog microphones with an integrated DAC to output a small amplitude signal. Or they can be a digital microphone - outputting a PDM stream of 1's and 0's.

    An audio codec like the TLV320AIC3106 on the LCDK can input either format.

    We also have an appnote that shows how to connect a digital microphone directly to the I2S/McBSP/McASP pins of a processor (and perform decimation and filtering with DSP on the signal to extract the audio). A software porting effort would be required to get it running on C6748 - see www.ti.com/.../sprac51.pdf

    Although there is an AIC3106 on the LCDK, you'd need to make some hardware modifications to connect a digital microphone - solder some wires to test points and maybe resistors.
    However, you should be able to connect an "analog" MEMS mic (that outputs an analog signal) directly to the MIC IN jack - using MICBIAS as its VDD.

    Similarly, you can take the Line Out signal from the AUDIO_OUT jack and run it into an amplifier like the TPA2012. There is a TPA2012D2 EVM that you could evaluate before integrating on your custom board. See www.ti.com/.../tpa2012d2evm

    In the AIC3106 datasheet, Figure 39. Typical Connections for Capless Headphone and External Speaker Amplifier shows the TPA2012D2 Class-D Spkr Amplifier connected to Line out signal of the AIC3106. We implemented this amplifier on the C5517 EVM if you want to take a look. www.ti.com/tool/tmdsevm5517

    Let me know your questions.

    Regards,
    Mark
  • 0 in reply to Mark M
    TI__Mastermind 29570 points
    Sorry, I didnt really address the MEMS speaker.
    This UT-P 2013 MEMS speaker I found on DigiKey (www.digikey.com/.../156 actually shows a reference schematic interfaced to a TI LM48580 Class-H piezo amplifier and TPS61046 boost converter (to get the required 15V).

    These are apparently options for MEMS speakers, and could be connected to the Line Out jack for evaluation.
    See www.ti.com/.../lm48580evm

    Regards,
    Mark
  • 0 in reply to Mark M
    Prodigy 20 points
    Thank you) you were very helpful.