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TPA6130A2 BTL input configuration

David McRell
Intellectual 445 points
Other Parts Discussed in Thread: TPA6130A2

Hello,

We are using TPA6130A2 in bridge-tied mode.  Per spec, we are using Left channel (-) as the input, and AC connecting (+) pin to ground.

What should we do with Right Channel inputs (pins 4 and 5)?  We -prefer- to not use caps in order to save precious PCB space.  Can we connect pins 4 and 5 directly to ground?   If a cap is required, is there a restriction on type (i.e., lytic vs. ceramic)?  Pros and Cons?

Depending on the answer above, can we short pins 2, 4, and 5 to a single lytic cap to ground?  Pros and Cons?

Kind Regards,

David McRell

  • 0
    TI__Guru**** 189401 points

    Hi, David,

    Thanks for posting! I have asked my colleague to work on this issue with you.

    -d2

  • 0
    TI__Intellectual 2710 points

    Hi,David,

    For BTL mode and SE input:

    1. Left channel(-) as input ,Left channel (+) AC couple to ground,we suggest to use ceramic cap,which has already mentioned in page 14 of datasheet.

    2. if you really want to save space,I think it doesn't matter that you directly connenct 4,5 pin to ground.

    Thanks,

    Flora Wang

  • 0 in reply to Flora Wang
    Intellectual 445 points

    Hello Flora,

    Thank you for your reply.

    Flora Wang said:
    2. if you really want to save space,I think it doesn't matter that you directly connenct 4,5 pin to ground.

    Ok.  So, are you saying it doesn't matter if pins 4 and 5 are both connected directly to ground, and therefore, it is moot to consider connecting pins 4 and 5 to ground via a cap?

    Also, if I may ask, is the max input signal ±3V peak, or ±3V  RMS?

    Many thanks,

    David McRell

  • 0 in reply to David McRell
    TI__Intellectual 2710 points

    Hi,David,

    Let me explain it more clearly.

    1.The Input-Blocking Capacitor is explained in page 13-14 of the datasheet. I think you have already understand it.

    2.For the BTL configuration, you have to configure the control register (address 1),and then use the left channel input, and connect the right channel to the GND to make it a certain state.From my understanding, AC couple to ground,the has some role to restrain the ground noise,but it really doesn't matter too much.

    3.The max input is -2.7V~3.6V peak,page 4.

    By the way,I don't understand why you want use TPA6130A2 BTL,the headphone is usually single end.

     

    Thanks,

    Flora Wang

  • 0 in reply to Flora Wang
    Intellectual 445 points

    Hi Flora,
    Thank you for your help.

    Flora Wang said:
    .From my understanding, AC couple to ground,the has some role to restrain the grond noise,but it really doesn't matter too much.

    Ok, we will have a provision for a cap, but will connect channel pins to ground.  I was looking for pros vs. cons, but it appears the cons are too small to matter.

    Flora Wang said:
    3.The max input is -2.7V~3.6V peak,page 4

    Ah, I had overlooked this asymmetry.  In this thread,
    http://e2e.ti.com/support/amplifiers/audio_amplifiers/f/6/t/289931.aspx

    Don Dapkus says, "The inputs are biased at ground, and can accept an audio signal of +/-3V amplitude."

    But, -2.7V peak = -1.91V rms.  I suppose 2.7Vp is close to 3V, but I will use 2.7Vp

    Regarding BTL: we are using qty 2 6130s for stereo balanced config.

    Many Thanks,
    David