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TPA6130A2 - Maximum Gain at THD < 1% for RL=16 ohms Stereo

James Evans
Mastermind 49692 points
Other Parts Discussed in Thread: TPA6130A2

Hi!

My application requires THD to be < 1%.

Based on the datasheet for the TPA6130A2 (Figures 3 through 6), the tested gains are 0.1 dB and 6.1 dB. The 6.1 dB plots are only for BTL though.

What is the maximum Gain with THD < 1 % for RL=16 ohms Stereo configuration at 100mW? 

I am concerned that increasing the Gain to 4dB would affect the THD performance at 100mW. When I look at the 16 ohm stereo plot below it shows good THD performance at 100 mW out, but it specifies a gain of 0.1dB.

If the THD would still be below 1% at 100mW out with 4 dB gain through the amp, I would use that gain. It would also allow me to reduce the required input swing of the amp by a factor of 1.58 (i.e. I would only need a swing of 2.3Vpp at the amp input if the THD performance is still good at 4 dB of gain). Does that make sense?

Thanks for your help in advance!!

James

  • 0
    TI__Guru**** 189401 points
    Hi, James,

    The THD performance across a small variation of gain (from 0.1 dB to 4.1 dB) is pretty much insignificant.

    In general, I recommend people use the lowest possible gain in the power stage of the signal path. This optimizes your SNR which is way more important than THD, IMHO. People can hear poor SNR, but we are less tuned (no pun intended) to "poor" THD.

    -d2
  • 0 in reply to Don Dapkus
    Expert 1220 points

    I would love to see people who can discern the difference between THD+N percent levels. I surmise these people have dog ears.
    Audio Precision had a presentation where crossover and clipping distortion were compared. Crossover distortion was far more objectionable at an order of magnitude lower than clipping distortion. I don't see how a single number means anything, IMO.


    -Ken