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TAS5815: Regarding the amplifier output peak voltage (V) in Table 7-2 of the TAS5815 datasheet.

takeru ishibashi
Prodigy 90 points

Part Number: TAS5815

Tool/software:

Regarding "AMPLIFIER OUTPUT PEAK VOLTAGE" listed in Table 7-2 of the TAS5815 datasheet, could you please tell me what exactly this value refers to?

Is it the peak value of either the positive or negative amplitude of the output signal?
Or is it the peak-to-peak value?

Regards,

Ishibashi

  • 0
    TI__Expert 5260 points

    Hi Takeru,

    it is peak voltage on output in theory. But in fact, it can't reach 29.5V as the power supply can't be so high. so 

    you can refer to the below doc:

    https://www.ti.com/lit/pdf/slaa894

    Br,

    Wenbin

  • 0 in reply to Wenbin Li1
    Prodigy 90 points

    Hi Wenbin

    Thank you for your response regarding the PEAK VOLTAGE above.

    I would also like to know how to interpret the Gain and PEAK VOLTAGE in this table, and whether the way of converting from dB to dBV is correct.

    This time, with a load of 8Ω and ANALOG GAIN of -0.5dB (all other gains at 0dB), a signal of -6dBFS (equivalent to an amplitude of 500mV) was input to I2S, and the output at the load was 9.647Vmrs. (When the input signal level is set to 0dBFS, the output waveform is clipped, so the measurement was performed at -6dBFS, where no waveform distortion occurs.)

    From this, the formula for calculating dBV, "20×log10(Vout/Vin)", converts ANALOG GAIN from dB to dBV to 25.71 dBV.

    If a signal of 0dBFS (equivalent to an amplitude of 1V) is input, the output level is 19.29Vrms using the above formula.
    If we calculate the PEAK value from this RMS value, we get 19.29Vrms × 1.414 = 27.28V, which is close to the PEAK value listed in the AGAIN <4:0>=0001 row of Table 7-2, and so this value is listed in the table.

    Are these interpretations correct?

    Regards,

    Ishibashi

  • 0 in reply to takeru ishibashi
    TI__Mastermind 20541 points

    hi Ishibashi

    your calculation is also correct.

    about the AG and DG setting, we also recommend reading above doc be shared.

    it can help you understand how the gain be set base on pvdd, speaker peak power.

    thanks

    jesse

  • 0 in reply to Jesse Ji
    Prodigy 90 points

    Hi Jesse

    Thank you for your reply.
    I understand that the series of calculations from determining dBV from output to calculating the PEAK value are correct.

    With that in mind, I have a question. Is there a dB/dBV conversion table for ANALOG GAIN?

    Regards,

    Ishibashi

  • 0 in reply to takeru ishibashi
    TI__Expert 5260 points

    Hi Ishibashi,

    there is no such a table. but I think you can just use excel to input the cal format like "=10^(A1/20)*29.5", here A1 is just a sample, it is the gain(dB) you should input, the output is the peak voltage (volt).

    Br,

    Wenbin

  • 0 in reply to Wenbin Li1
    Prodigy 90 points

    Hi Wenbin

    I understand that there is no conversion table.
    I will try to calculate dBV using the formula you provided.

    Regards,

    Ishibashi

  • 0 in reply to takeru ishibashi
    TI__Mastermind 20541 points

    hi Ishibashi

    sure, if you have any more questions, you can add comment here.

    let me close this ticket currently.

    thanks

    jesse