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TAD5142: Output Configurations

Sadanori Kato
Guru 36540 points
Part Number: TAD5142

Tool/software:

Hi,

Could you please let me know if the following four output configurations are possible for TAD5142?

Best regards,
Kato

  • +1
    TI__Mastermind 25540 points

    Hello ,

    Please refer the the Table 6-9. Analog Output Configurations and 6.10 to see all the possible configurations including for psude and full differential.

    Load of 32Ohm should be fine as 8 to 300 Ohm is the acceptable load range,

    Figure 4-9. TAD5142 EVM Main DUT Schematic  in users guide shows the jumper options for AC or DC coupling and it is fine to me.

    Regards,

    Arash

  • 0 in reply to Arash Loloee
    Guru 36540 points

    Hi Arash-san,

    Thank you for your information.

    Could you please let me confirm just in case as TAD5142 EVM allows for flexible output configuration?

    Regarding "Pseudo-differential Output Configuration (a)", the pseudo-differential output converts to a single-ended output. Are there any concerns?

    Regarding "Pseudo-differential Output Configuration (b)", the output configuration is changed to reduce the current consumption due to the 100kΩ dummy load as follows. Are there any concerns?

    By the way, the above two output configurations have a loading of over 30Ω when the headphone jack is not plugged in. This is out of specification. Are there any concerns?

    Best regards,
    Kato

  • +1 in reply to Sadanori Kato
    TI__Mastermind 25540 points

    Hello,

    The allowed range of load is from 8 to 300 ohm, so 30 or 32 Ohm load is ok but not 100k. I don't think there is any concern with either cases you have for pseudo differential above ( except the 100kOhm)

    Regards,

    Arash

  • 0 in reply to Arash Loloee
    Guru 36540 points

    Hi Arash-san,

    Thank you for your prompt reply.

    If a load of over 300Ω is expected to be connected to the output included no load, in other words, when the headphone jack is not plugged in. Is my understanding correct that the following workarounds will be required?

    - Workaround 1
    An external circuit detects when the headphone jack is plugged in and the host controller begins to supply the I2S clock as TAD5142 doesn't have a shutdown or mute function.

    - Workaround 2
    First, the output configuration is set to line out mode. The output configuration should be change to pseudo-differential output mode when the headphone jack is plugged in.

    I think it would be very difficult to use the TAD5142 if it doesn't work normally without load as a headphone amplifier, but are there any concerns about oscillation for TAD5142?
    I would appreciate any advice on how to avoid this.

    Best regards,
    Kato

  • +1 in reply to Sadanori Kato
    TI__Mastermind 25540 points

    Hello Kato-San,

    TAD5142  has internal Jack and headphone detection,  so no need for external circuit to detect when headphone is plugged in.

    Every single DAC that I know has a load capability specified in its datasheet,  the load capability for TAD5142 in Headphone configuration  is from  8 to 300.

    This DAC belongs to  the latest and  top of the line family of devices and I don't think there is any concern using it.

    Regards,

    Arash

  • 0 in reply to Arash Loloee
    Guru 36540 points

    Hi Arash-san,

    Thank you for your information.

    I found the following application note regarding "Headset Detection for TAx52xx Family". However TAD5142 is the audio DAC and doesn't have a MICBIAS output such as the audio CODEC, so I don't think TAD5142 supports headset detection.
    If TAD5142 has the internal jack and headphone detection, could you please share application note for TAD5142 headphone detection with me?
    Additionally, can TAD5142 automatically switch from sleep mode to operation mode when the headphone jack is inserted?

    www.ti.com/.../slaaeg7.pdf

    Best regards,
    Kato

  • 0 in reply to Sadanori Kato
    TI__Mastermind 25540 points

    Hello,

    For any product, all the available application notes are in the product page. The TAX5XXX family of devices  has internal jack  and headphone detection whatever is applicable (Codec has both, DAC has headphone detection ) . I will check with design team about your question regarding TAD5142  sleep mode in specific and will get back to you.  Since it is a holiday this week,  I will let you know by next Tuesday,

    Regards,

    Arash

  • 0 in reply to Arash Loloee
    Guru 36540 points

    Hi Arash-san,

    Thank you for your quick response.

    I have an additional easy question.
    Is my understanding correct that the audio signal shouldn't be output when there is no load as TAD5142 has the internal jack and headphone detection?
    Otherwise, I don't see any reason for TAD5142 to have detection function.

    Best regards,
    Kato

  • 0 in reply to Sadanori Kato
    TI__Mastermind 37705 points

    Hi,

    Today is a holiday for our team in the U.S. We will follow up when our team returns on Friday.

    Thank you for your patience,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Guru 36540 points

    Hi Jeff-san,

    Thank you for following up on this.

    I'm looking forward to getting any updates next week.

    Best regards,
    Kato

  • +1 in reply to Sadanori Kato
    TI__Mastermind 25540 points

    Hello Kato-San, Thanks for your patience while I was gathering info from design team. The below sums up your inquiry.

    The Jack detection feature in this family of devices , works only with MICBIAS output pin(only commercial variant , not on automotive) having a biasing resistor externally. So we do not have jack detection for TAD5142
    There is No intelligence on the device to switch from sleep to operation mode based on Jack detected. It just raises interrupts and flags for insertion, removal 

    Regards,

    Arash

  • 0 in reply to Arash Loloee
    Guru 36540 points

    Hi Arash-san,

    Thank you for your information.

    The no load is out of specifications when using TAD5142 with a headphone amplifier output. So, is my understanding correct that the I2S clocks should be applied to TAD5142 after detecting the headphone jack?

    Best regards,
    Kato

  • +1 in reply to Sadanori Kato
    TI__Mastermind 25540 points

    Hello Kato-San,

    I2S can be there all the time, I think what you are concerned is powering up the DAC block after detection the headphone jack.

    Regards,

    Arash

  • 0 in reply to Arash Loloee
    Guru 36540 points

    Hi Arash-san,

    Thank you for your quick response.

    I2S clocks should always be applied to TAD5142, but could you please tell me what is the recommended operating procedure if assuming no load?
    If TAD5142 can work normally with no load, then this concern will be alleviated.

    Best regards,
    Kato

  • +1 in reply to Sadanori Kato
    TI__Mastermind 25540 points

    Hello Kato-San, 

    TAD5142 can work normally without load .

    Regards,

    Arash

  • 0 in reply to Arash Loloee
    Guru 36540 points

    Hi Arash-san,

    Thank you for your quick response.

    I understanad.

    Best regards,
    Kato