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Digital microphone help

Charlie Mydlarz
Prodigy 30 points

Other Parts Discussed in Thread: TLV320ADC3101, DIT4096, PCM2902C, TMS320C5533, PCM2706, PCM2706C

Hi there!

Im designing a USB digital MEMS microphone board for a large scale noise sensing project. I have the option of using the following 2 digi mics:

Can anyone suggest an audio IC that can take either a PDM or I2S input and provide a USB audio compliant interface to act as a sound input device (at 44.1 or 48kHz) for a linux based mini PC?

Ive looked at solutions involving MCUs, but the extra level of complexity to get the software side up and running is offputting.

Ive been looking at the TLV320ADC3101, which can handle a digi mic PDM input, but would require a USB audio interface IC in addition to it. This is still a possibility though.

Any advice would be much appreciated!

Charlie

  • 0
    TI__Guru** 114015 points
    Hi Charlie,

    Welcome to E2E and thank you for your interest in our products!

    I'm afraid that we don't have a USB integrated audio device that supports digital microphones. PCM270xC USB DAC family supports only analog input signals. PCM290xC USB Codec family supports only analog and S/PDIF input signals.
    But as you suggested TLV320ADC3101 with an USB interface IC is an option.
    Let me know if you need more information.

    Best regards,
    Iván Salazar
    Texas Instruments
  • 0 in reply to Ivan Salazar
    Prodigy 30 points

    Thank you Ivan!

    One of the mics Ive been looking at can output a 24bit I2S signal: ICS-43432

    Do you stock a USB audio interface that could take this I2S as a digital input signal and provide a SCK of 3.072/2.8224MHz for 48/44.1kHz audio?

    Or can you suggest another USB interface that can take whatever digital output the TLV320ADC3101 provides?

    Huge thanks!

    Charlie

  • 0 in reply to Charlie Mydlarz
    TI__Guru** 114015 points
    Hi Charlie,

    An I2S to USB interface can be a combination of USB codec like PCM2902C with S/PDIF input and DIT4096 which converts I2S to the S/PDIF.
    Another option is to use TMS320C5533 which is the replacement part for TAS1020B.

    Best regards,
    Ivan Salazar
    Texas Instruments
  • 0 in reply to Ivan Salazar
    Prodigy 30 points

    Hi Ivan,

    That combo looks like a possibility.

    Im also interested in the PCM2706 and PCM2707. These two seem to have I2S input pins. One of the MEMS mics Im using outputs a 24bit I2S signal. Will these two TI devices handle this I2S signal from the microphone?

    Id ideally like to use a 44.1kHz sample rate for the digital audio but can make do with a 48kHz rate if 44.1 isn't possible. This would mean the PCM270x device would need to produce a 3.072MHz SCK frequency for the mic (@48kHz LRCLK) or 2.8224MHz for a 44.1kHz LRCLK rate.

    What Id really like is something that works out of the box so no EEPROM programming or registry setup. So when connected to the USB host PC, it enumerates as a mic input device and spits out the correct clock rates and handles the i2S in with the minimum of fuss!

    Cheers!

    Charlie

  • 0 in reply to Charlie Mydlarz
    TI__Guru** 114015 points
    Hi Charlie,

    These PCM2706C and PCM2707C are DAC family; the I2S input signal cannot be send to the USB.
    I'm afraid that these devices may not be suitable for this application.

    Best regards,
    Ivan Salazar
    Texas Instruments
  • 0 in reply to Ivan Salazar
    Expert 1680 points
    Hello Ivan,
    I also wonder what's PCM2707C I2S in & out application.
    Does I2S input just for PCM2707C internal DAC input , to get L/R analog out ?
    The I2S output from PCM2707C,is it from USB ? For external I2S device ex: DAC or DSP ?
    Many thanks ~