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PCM6020-Q1: MIC interfacing with DAC for Instrument cluster applicationf ro 24V system for Hands free

Manoj Agarwal
Prodigy 180 points
Part Number: PCM6020-Q1
Other Parts Discussed in Thread: PCM3120-Q1

Tool/software:

Dear Team, we need to interface MIC for to system for hands free application for instrument clusterMIC Interfacing for hands free. Please let me know suitable IC. We were thinking of PCM60202Q1. But need to check for single channel IC also. Attached is our mic and interfacing arrangement. Please suggest.

  • 0
    TI__Mastermind 48205 points

    Hi Manoj,

    PCM6020-Q1 is fine. However for low level signals like microphones, I would recommend the PCM3120-Q1 instead since it has better performance for low level signals.

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 180 points

    Any single channel IC in place of PCM3120-Q1.

    2. This is second query; I have one audio amplifier out which is to be monitored for Chimes. Can you suggest any circuit which amplifier out to be given to one channel of PCM3120. Amplifier out could be up to 2 to 3W for chimes in vehicle. 

  • 0 in reply to Manoj Agarwal
    TI__Mastermind 48205 points

    Hi Manoj,

    Which amp have you selected? As long as the voltage is below 2Vrms differential, the PCM3120-Q1 can measure it fine. The ADC can be connected parallel to the speaker load.

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 180 points

    Hi Jeff.

    1. I have two requirement one i s MIC interface for calling.  MIC spec is given. 

    2. Speaker feedback is to be monitored. I have used TAS6501/TAS6511 amplifier for Audio warning. 

    Please provide single channel IC as we may need only one channel on some variant.

    Also confirm if in PCM3120-Q1 (Dual channel) One channel could be used feedback form speaker and other channel could be used for MIC interface. Our host interface is I2S.

  • 0 in reply to Manoj Agarwal
    TI__Mastermind 48205 points

    Manoj,

    There is no mono ADC that will work for you here. Most of our catalog is 2 channel minimum. 

    For a 2W output to 4ohms will be about >3Vrms which is higher than the 2Vrms maximum of the PCM3120-Q1 ADC. The PCM6020-Q1 would be better for this, despite the tradeoff on mic dynamic range.

    However the TAS6511/TAS6501 can output current sense data via I2S. I think you will be better off not using any external circuitry to sense the output since the amp can do that on its own. Then the ADC can be used for the mic only.

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 180 points

    Hi Jeff,

    I have one more query regarding PCM3120-Q1 ADC. In our application MIC+ and MIC- signals coming from vehicle environment so need to know about protection capability of PCM3120-Q1 or PCM6020-Q1 device for short to BAT (24V truck cluster application) and other test as per ISo7637 for signals lines.

    Regards

    Manoj A

  • 0 in reply to Manoj Agarwal
    TI__Mastermind 48205 points

    Hi Manoj,

    The PCM6020-Q1 has input fault diagnostics including a short to VBAT condition. PCM3120-Q1 does not have this.

    However 24V is higher than the absolute maximum supported by the pins of either device. The diagnostics will not work for a 24V battery, it must be 18V or lower. So I recommend using external clamping diodes to prevent the input pin voltage from reaching 18V or higher.

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 180 points

    Hi Jeff,

    Thanks for guiding us .

    I see PCM60202 would be good choice for following reason.

    1. Our MIC need 8V bias and This device provide biasing till 9 V.

    2. It provide diagnostic for Open/Short input. Short to GND, MICBIAS VBAT. Need to check for 24V short to Bat case protection using external components. During schematic review you can suggest these components or any protection IC for the same.

    Please share development board schematic.

     3. Query: As our MIC is 2 Meter away from board, would MIC+ and MIC- would be directly connecting with INP and INM pins of of PCM 60202 through AC coupling.

    4. We may need your support for schematic review. Request you to connect over email.

    Regards

    Manoj A

  • 0 in reply to Manoj Agarwal
    TI__Mastermind 48205 points

    Hi Manoj,

    I match your understanding. I have sent you a connection request here on e2e and I can give you my email there for when you are ready for a schematic review.

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 180 points

    Hi Jeff, As I see Battery voltage for us ranging for 24V system (18-32V) for 24V system so we cannot connect VBAT directly to VBAT_IN our use case. what is your suggestion here to use this IC for 24V system. Do we need to provide voltage divider circuit to provide VBAT correspond to 0 to 18V recommended voltage input also what recommended device to be used for protection at IN1P and IN1N. 

  • 0 in reply to Manoj Agarwal
    TI__Mastermind 48205 points

    Hi Manoj,

    A input short to VBAT will be detected as long as both VBAT_IN and the input pin are at 11.7V or higher. I recommend Using a passive divider to bring the battery voltage down to <18V. Use high value resistors so that current is not drawn away from the battery.

    I don't know much about the clamping diodes we offer since that's covered by a different team. The breakdown voltage will be much higher than the audio input voltage so I don't expect this to impact audio quality regardless of which diode you pick. At a glance I did find this diode which is automotive qualified and has specs that make sense for this application

    https://www.ti.com/product/TSD15-Q1

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 180 points

    Hi Jeff,

    Is current consumption for PCM6020 considered is correct.

    IOVDD(1.8V): 1 mA, AVDD(3.3V): 2mA, BSTVDD(3.3V): 18mA.

  • 0 in reply to Manoj Agarwal
    TI__Mastermind 48205 points

    Hi Manoj,

    Those numbers seem reasonable, though AVDD is very low so I assume the device is still in sleep mode/ there is no activity.

    You can refer to this app note which gives AVDD and BSTVDD current numbers across various different scenarios. https://www.ti.com/lit/an/sbaa500a/sbaa500a.pdf?ts=1759865426402&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FPCM6020-Q1

    IOVDD is going to be very small since it is just a supply for the IO voltage.

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 180 points

    Hi Jeff,

    I want to confirm active mode current for power budget estimation to design power supply. Please tell actual current to be considered  for this. Including. I will go through app note

    Attached is MIC spec. Also we are dring MIC baising from IC itelf, MIC boasing is 8V. 

    IOVDD(1.8V): 1 mA, AVDD(3.3V): 2mA, BSTVDD(3.3V): 18mA.

  • +1 in reply to Manoj Agarwal
    TI__Mastermind 48205 points

    Hi Manoj,

    The power supply for this device is going to be dominated by the BSTVDD draw. With a 6mA load on 8V MICBIAS, BSTVDD will draw approx 30mA. 

    You will have to use the app note to double confirm the AVDD numbers, but I'm assuming about ~20mA based on the most typical use case. 

    IOVDD will again be negligible in comparison. 1mA is a good estimation for budgeting.

    Overall you should provide for at least 51mA. 55mA is a good margin.

    Best regards,
    Jeff McPherson