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TPA2005D1: about TPA2005D1's Quiescent Current

huo574
Prodigy 20 points
Part Number: TPA2005D1

We use the schematic as below and found the current was very big(0.38A) without input signal(shutdown pin is high).

But the Quiescent Current was very low in datasheet(if shutdown pin is low at this condition?).

Would you tell me if our IC was damaged.

If not, whait's wrong in our schematic.

Thank you very much! 

  • 0
    TI__Guru** 109055 points

    Hi Huo,

    Can you try a couple things to better understand what could be causing increased quiescent current:

    • Please disconnect the speaker from CN7, then check current consumption.
    • Do you have ZX01 and ZX02 populated? If you do, please try removing these and then check current consumption.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Prodigy 20 points

    thanks for your answer.

    ・Please disconnect the speaker from CN7, then check current consumption.
    　→ the current has no change.
    ・Do you have ZX01 and ZX02 populated? If you do, please try removing these and then check current consumption.
    　→ the current has no change.

    the current changed from 0.01A → 0.38A when I turned the Vcc from 5V → 3V.
    Does that means the Vcc supply must above 3V?

  • 0 in reply to huo574
    TI__Guru** 109055 points

    Hi Huo,

    Thanks for the information. The minimum recommended VDD for TPA2005D1 is 2.5V, so using 3V should not be a problem, but it seems to be definitely related.
    I would suggest inspecting all the passive components related to VDD. Can you double check how the voltage changes across DX01?

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Prodigy 20 points

    Thanks again for your reply.
    The current is same Without DX01.
    I test another IC just with shutdown pin pull up, and adjust the voltage of VCC from 2.5V to 5V, the current was 20-30mA.
    When I connected input pin with 1kHz 0dB signal the current increased from 30mA to 300mA(VCC=2.5V).
    And disconnected input signal the current was still maintain about 300mA.
    I thought maybe all ICs were damaged.

  • 0 in reply to huo574
    TI__Guru** 109055 points

    Hi Huo,

    I don't have an EVM at hand to double check this on my side, but I've requested one that should come in a few days. In the meantime, I'll check if the models available can give an idea of the possible root cause. It's hard to believe that all units are damaged, so it may be something else affecting the performance of the amplifier.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    TI__Guru** 109055 points

    Hi Huo,

    I've run some tests with our EVM, I may have identified a possible root cause, test was resulting OK until I noticed that when I disconnect one of the cables from the differential pair, the current increased to ~200mA. Then I test with single-ended input and idle current is ~50mA, again if I disconnect either cable from the input, current increases again to ~200mA. On both differential and single-ended cases, the current goes to very low values if I disconnect both cables. Next thing I re-test every case, but adding a direct GND connection between the power supply and the test equipment (both input signal and output measurement) and the current is back to low values regardless of the input differential/single-ended cables.

    In conclusion, there may be a GND break in your test setup, either within the system from the audio source to TPA2005D1, or form either side to the power supply GND.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Prodigy 20 points

    HI  Ivan !

    Your reply solved my problem,thanks for your help!

    Thank you!

    Thank you very much!

    Best regards,

    Huo