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PCM2912A: Please suggest the part which can support the headphone/microphone and USB interface.

George Liu1
Intellectual 1570 points
Part Number: PCM2912A
Other Parts Discussed in Thread: PCM2900, PCM2900C, PCM2902C

Hi Sir,

Please help to suggest a part to our customer which support the Headphone/Microphone and USB interface for Audio portion.

There have additional spec for your reference:

1. Support Headphone and Line out, and output can reach 2Vrms.

2. (Optional) Headset OMTP/CTIA detection.

3. USB as a UAC device

4. Analog Mono Mic support but not decide the Differential or Single-end yet.

Looking forward to hearing from you soon.

Thanks,

George

  • 0
    TI__Intellectual 1570 points

    Not sure PCM2912A can be the candidate or not, please advise.

  • 0 in reply to George Liu1
    TI__Guru 63985 points

    Hi George,

    The PCM2912A supports a mono-ADC input that is typically used with microphones and also line/headphone outputs.  The headphone outputs are 0.55*VCCA Vpp into a 32Ohm headphone load.  

    VCCA is nominally 3.3V so the typical peak-to-peak output voltage into a headphone load is 1.815Vpp or roughly 0.64VRMS which looks to be a little lower than you're hoping.

    Can you help clarify on the # of ADC inputs, # of DAC outputs required?  I wasn't sure if some of the voltage levels you were asking about were inputs or outputs.

  • 0 in reply to Collin Wells
    TI__Intellectual 1570 points

    Hi Collin,

    Thanks for your comments.

    Currently, customer are not provide their requirement fully, only some items for us to find the candidate to them.

    Will ask them for the detail, but we can share PCM2912A to them firstly.

    BTW, for #2 did PCM2912A can support the jack type detection?

    Thanks,

    George

  • 0 in reply to George Liu1
    TI__Intellectual 1570 points

    Hi Collin,

    Sorry one more question, if you got any better candidate which can support Headphone output around 2Vrms, Mono mic input and also can support the USB interface... please share to me.

    Thanks,

    George

  • 0 in reply to George Liu1
    TI__Intellectual 1570 points

    Hi Collin,

    I lost 1 item that from customer requirement.

    The output SNR should more than 95dB, I think PCM2912A cannot meet their expectation.

    Looks PCM2900/2902 can reach their idea, could you please help to review it if PCM2900/2902 will be much suitable for them?

    1. Support Headphone and Line out, and output can reach 2Vrms.

    2. (Optional) Headset OMTP/CTIA detection.

    3. USB as a UAC device

    4. Analog Mono Mic support but not decide the Differential or Single-end yet.

    5. Output SNR should more than 95dB.

    Thanks,

    George

  • 0 in reply to George Liu1
    TI__Guru 63985 points

    Hi George,

    PCM2900C looks to meet some of, but not all of your requirements.  SNR is 96dB on the analog output, but the output level is still going to be the same as the PCM2912A.

    1.)  You're asking for 2Vrms (5.6Vpp) but USB supplies are only+5V.  You'll need a boost in your system somewhere to achieve a 2Vrms output.  The PCM2912A has an integrated headphone amplifier, the PCM2900/2C do not so you'd need to add an external headphone amplifier anyways and you can find one that will boost the PCM29xx outputs to the desired 2Vrms levels.

    2.)  Not included

    3.)  Yes, these are UAC1.0 devices.  For information on how to use them with UAC2.0 default systems see this link:  https://e2e.ti.com/support/audio/f/6/t/778101?PCM2906C-PCM2906C

    4.) Supported directly on PCM2912A - you'll need a MICBIAS and pre-amp w/ the PCM2900/PCM2902C

    5.)  PCM2900/2902:  96dB, PCM2912A: 92dB.  Remember, you'll need an external headphone amplifier with the PCM2900/2902 which may negatively impact the SNR of the PCM2900 if not designed properly.

  • 0 in reply to Collin Wells
    TI__Intellectual 1570 points

    Hi Collin,

    Thanks for your quick reply, very detail and clarify to me.

    I will share our discussion to customer, and try to guide them for their project design, hope we can DIN the project.

    Thanks,

    George