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Original question:

TLV320AIC3111EVM-K: Unable to test on-board microphone on the AIC3111 EVM

TLV320AIC3111EVM-K: What speaker and microphones can be used with the eval board

Mitesh Hiran
Mastermind 6215 points
Part Number: TLV320AIC3111EVM-K
Other Parts Discussed in Thread: TLV320AIC3111

Hello, we have TLV320AIC3111 EVM board and working out the best speaker and microphone can be used on the eval board as external components and test the AGC feature of the codec. 

From datasheet:

  1. Headphones must be 16 Ohms 60mW or 32 Ohms with 20mW.
  2. Speaker to be Stereo 8 Ohms differential around 790mW to 1.29W (basically 400mW per channel)
  3. What would be for microphone? 

Are these details enough to filter the speakers and headphones? 

Thanks  

  • 0
    TI__Mastermind 20615 points

    Hello Mitesh,

    Thank you for reaching out. 

    #1. and 2. Are correct.

    As for #3, the AIC3111 can work with either digital or analog mics.

    When selecting a mic from the CODECs point of view the main specs to consider are:

    • input signal level (full-scale for the AIC3111 is 0.707) - this is not relevant if a digital mic is used.
    • input impedance (for best performance match the microphones values close to one of the options available in page 1 / register 48 and 49), 
    • what type of MICBIAS options are needed (see options available in 5.5.1 MICBIAS and Microphone Preamplifier)

    I hope this helps, let me know if you have further questions.

    Best,
    Andrew

  • 0 in reply to Andrew Jackiw
    Mastermind 6215 points

    Hi Andrew, thanks for your response. 

    1. For the input impedance of microphone, what is set for the eval board please? (I mean for on the PCB not the register set)

    Thanks 

  • 0 in reply to Mitesh Hiran
    TI__Mastermind 20615 points

    Hi Mitesh,

    The input impedance should be the impedance of the microphone capsule itself (listed on the manufacturer's datasheet). Therefore, EVM does not have a input resistor and the user can decide how to set the feed forward resistance in page 1 / register 48 and 49 to best fit the microphone.

    However, this is optional, and the application will work with default register settings.  

    Best,
    Andrew