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TAS2505-Q1: Waveforms of SPKP , SPKM and SPEAKER

Jerry Hsueh
Expert 2730 points
Part Number: TAS2505-Q1


Hi

Do you have the voltage waveform of SPKP and SPKM and the current waveform of SPEAKER when TAS2505-Q1 plays sound for our reference?

Thank you

Jerry

  • 0
    TI__Guru* 84915 points

    Hi, Jerry,

    I took some captures of the voltage waveforms at the SPK outputs of the TAS2505-Q1. The TAS2505-Q1 is configured with a speaker driver gain of 12dB. I used a 1-kHz full-scale digital sine wave signal and 48KHz sampling rate. Yellow waveform is the SPKP output and Blue waveform is the SPKM output. Red waveform is the difference between both signals. This was directly measured on a 4ohms speaker load.

    Then, if the outputs are filtered with an LC-filer, the outputs became clearer and easier to analyze.

    Regarding the current waveforms, it is important to mention that the current will vary from speaker to speaker. Each speaker load has its own characteristics. However, in general all the current waveforms follow some forms depending of how much voltage is applied. Please take a look at picture below for details:

    I hope this helps. Please let me know if you require additional information.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Expert 2730 points
    Hi Luis

    Thank you very much for your help.
    BTW, Can SPKP and SPKM output be capacitively coupled? How much capacity does it need to use?

    Jerry
  • 0 in reply to Jerry Hsueh
    TI__Guru* 84915 points
    Hi, Jerry,

    The SPKP and SPKM outputs don't require capacitors since they can be directly connected to the speaker terminals. However, for cases where it is important to reduce effects such noise, pF capacitors may be connected from SPKP and SPKM outputs to GND. We don't recommend to connect capacitors higher than 0.01uF since they may affect signal behavior.

    Best regards,
    Luis Fernando Rodríguez S.