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TAS5727: Could not pas HD DTS test

Robin Yu
Intellectual 2190 points
Part Number: TAS5727
Other Parts Discussed in Thread: TAS5538, TAS5352,

Our customer has done the HD DTS certification test, but has failed. While another one TAS5538+TAS5352 has passed.

In the test, the signal source will output 3 kind of signals in different frequency (30Hz, 1KHz and 12KHz), the load is 8Ohm and power is 1W. The requirement is the harmonic wave at other frequency must not exceed its range. But in the test results, harmonic wave at 10kHz and 14kHz is beyond the requirement. (requirement is not exceeding -70dB, but actually is exceeding -60dB).  While for TAS5352, both under -80dB.

Please see attachment.

In addition, power supply is 20V. And it has passed EMC test.

Look forward for your replying.

Thank you.

8 ohm 3 tone for 5727.pdf

8 ohm 3 tone for 5352.pdf

  • 0
    TI__Expert 3345 points
    Hi Robin,

    Would it be possible to send over the BOM for the TAS5727 design? This may be a matter of component quality, and we can review the BOM to see if we have any suggestions in that regard.

    I'll send you a connection request so we can exchange the BOM.

    Regards,
    Brian Angiel
  • 0 in reply to Brian Angiel
    TI__Intellectual 2190 points

    Hi Brian,

    Please see attachment, schematic and BOM.

    They have also tried another inductor as below, same result.

    08-04150-16

    24-1-000074

    inductor

    INDUCTANCE

    744066150

    L3, L6, L7, L8

    ppa3-amp.pdf

    PPA3-G3-NEW PARTS LIST-amp VC1 0.xlsx

    Thank you.

  • 0 in reply to Robin Yu
    TI__Expert 3345 points

    Hi Robin,

    I have a couple recommendations for your customer:

    1. Evaluate several inductors. These are tricky as datasheet specs alone cannot determine which inductor will offer you the best performance. It would be beneficial for your customer to gather a collection of quality inductors and test them in the lab.
    2. This is an open loop amplifier, so any noise on the PVDD line will be coupled into the audio signal. So it's important that the PVDD lines are as clean as possible. If they haven't already, ask your customer to use a DC power supply from their lab to power their system and see if their results improve.

    I hope this is helpful to you and your customer. Please let me know if you have any other questions.

    Regards,

    Brian Angiel

  • 0 in reply to Brian Angiel
    TI__Intellectual 2190 points

    Hi Brian,

    Thanks for your reply.

    Some information need to confirm.

    1. The inductor you mentioned is used for output filter?

    2. You mean the power rail "VCC_PVDD20V3" may be not clean?

    Robin

  • 0 in reply to Robin Yu
    TI__Expert 3345 points
    Hi Robin,

    Yes, I am referring to the output filter inductor and VCC_PVDD20V3 lines. I apologize, I should have been more specific.

    Regards,
    Brian Angiel