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TPA2001D1: No audio output

Vitaly And
Prodigy 180 points
Part Number: TPA2001D1
Other Parts Discussed in Thread: TPA2005D1

Hello,

we have several boards with no audio from TPA2001D1 after approximate one year of operation.

We have replaced one capacitor (Cosc) and the sound is now ok. On some boards we have replaced two capacitors (Cosc and Cbypass).

We use 06033A221JAT2A AVX for Cosc and 0402ZD105KAT2A AVX for Cbypass.

If we install these "bad" capacitors into a some "good" board with TPA2001D1 then we have no more sound. But these "bad" capacitors are perfectly working in some other "good" boards. We have measured the capacitance and it is ok.

What should it be? Are our capacitor partnumbers correct? There are very few requirements for these capacitors in the datasheet, does any additional information exists? Are the recommended capacitors from the datasheet tested for some long time?

Thank you.

  • 0
    TI__Guru* 95225 points

    Hi Vitaly,

    The issue description sounds odd.
    I'll do some further investigation on this kind of issues and will provide some additional information as soon as possible.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    Prodigy 180 points

    Hi, Ivan,

    thank you, here are some additional info:

    On the attached schematic the components labeled with *) are not installed on board.

    We use the TPA2001D1 in singe ended input fashion and an output filter based on inductors.

    On some boards we get a working audio by simply touching the 14 pin (Cosc) with a oscilloscope probe or even with a short wire like antenna.

    Is the output filter correct? Can it lead to internal protection activation?

  • 0 in reply to Vitaly And
    TI__Guru* 95225 points

    Vitaly,

    Toching the Cosc pin with a scope probe still seems like capacitance modification, similar to changing Cosc capacitor.

    • When the device is not working, is there absolutely no audio at the output? If you capture the output signals (without filter) is there a noticeable difference between good and bad operation?
    • I think the PVDD supply decoupling is not shown in the schematic. Have you followed the recommended supply decoupling capacitors for these pins?
    • Regarding the output filter, I would only suggest to remove C83.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    Prodigy 180 points

    Ivan,

    1. Yes, absolutely no signal. But we do not remove the filter for this measurement. Do you think we should remove it?

    2. Yes, capacitors are not shown but are installed near the device according to recommendations.

    3. Have tried this without success...

  • 0 in reply to Vitaly And
    TI__Guru* 95225 points

    Vitaly,

    You could capture some scope shots without the filter, or place the scope probe before the filter. What I would like to know is if the Class-D output is actually switching or is it powered down for some reason.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    Prodigy 180 points

    Ivan,

    absolutely no signal (probed at output pins before filter), plain straight line, no switching. Looks like is in shutdown or fall into some protection state. The shutdown pin is of course in high state.

  • 0 in reply to Vitaly And
    TI__Guru* 95225 points

    Vitaly,

    Then it seems that the device triggers a protection. Unfortunately it seems to be related to the external capacitor.

    You could change from TPA2001D1 to TPA2005D1. This device has completely internal oscillator so there is no need for external RC.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators