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TPA2011D1: TPA2011D1 1K sine wave

Lawrence He
Genius 3280 points
Part Number: TPA2011D1
Other Parts Discussed in Thread: TPA3132D2

Dear,


out client use TPA2011D1 amp, but find the question.

schematic as below chart:


R986, R987 change to 300k ohm and B82/B82 (Bead) was remove.

LINE 2 :input waveform 1K sine wave

speaker out measument waveform

what`s going on? it`s normal?

if any suggestion, Please advise me.

Thanks,

Best regards,

Lawrence.

  • 0
    Guru 140200 points
    Hi Lawrence,

    when you change R986 and R987 to 300k, you must also change R985 to 150k.

    Kai
  • 0
    TI__Mastermind 20085 points
    Hi Lawrence,

    I will be responding on Monday with further information.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer
  • 0
    TI__Mastermind 20085 points
    Hi Lawrence,

    It could be a decoupling problem. Are the decoupling capacitors placed close to the device? They should be placed within 2 mm of the Vdd Pin if this is possible. You can refer Power Supply Decoupling Capacitors section of the amplifier's datasheet to find further information.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer
  • 0 in reply to José Luis
    Genius 3280 points
    Hi, José Luis

    Thank you for help, we will check decoupling cap.

    Best regards,

    Lawrence.
  • 0 in reply to Lawrence He
    Guru 11785 points

    Hi Sirs,

    Thanks for your reply.

    Update our problem.

    As we know if you want to get the sine wave, you need external LC on AMP output, right? 

    But we saw what is mean on TPA2011D1 datasheet, It's mean don't need this LC is ok? or?

    By the way, we tried to decoupling cap and have same phenomenon.

    We have do same test on TPA3132D2, looks it's could normal get sine wave result on output.

    Thanks!!

     

  • 0 in reply to Shu-Cheng LIN
    TI__Mastermind 20085 points
    Hi Shu-Cheng,

    TPA2011D1 doesn't need to LC filter to get a sine wave as this device uses the inductance of the speaker to create a sine wave. Most of TI's Class-D amplifiers operate without a filter when speaker wires are less than 10cm. However, you should use an LC filter or ferrite bead filter as close as possible to the amplifier's output pins for very stringent Electromagnetic Interference (EMI) requirements.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer