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Original question:

TPA3251: TPA3251 Issue

TPA3251: TPA3251 Issue clipping spike

Darrell Pruehsner
Prodigy 80 points
Part Number: TPA3251

I see this thread is exactly what I am seeing with my design.  But the text refers to PVDD de-coupling cap being changed, I see none in his schematic.  does he mean DVDD cap?   This type of distortion at 101% drive is not acceptable for my application. 

  • 0
    TI__Guru 65450 points
    Darrell,

    If you are seeing dips in the sine wave at 101% drive, this is the Cycle-By-Cycle Current Control, if you look at the PWM waveform you should see pulses being skipped as well.

    The amps are not designed to run at 101% drive and the amp is trying to protect itself and also limit the THD in that region.

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 80 points
    I have verified all 50 units do this. It is NOT a current limit problem since no load is needed, it is input inversion upon overdrive. I had to figure this out for myself. TI did not really help, I understand debugging long distance is difficult. I also checked and verified the heat sink was at ground and contacting the heat PAD on the part. The only thing that helped is limiting the input drive signal. You claim you can drive your EVAL unit with 12 p-p input without a problem, if really true then this entire production run of parts have a problem. I want to help TI make these stuff better, a difficult task when info like this is not passed along to the design, product, and test engineers. Where all the previous post of this thread have gone is interesting. I have a copy.
  • 0 in reply to Darrell Pruehsner
    TI__Guru 65450 points
    Darrell,

    The other post is here: e2e.ti.com/.../2684133

    It was closed because I cannot leave threads open. The post is not hidden and no one is doing anything to hide any details.

    If you have further questions, please reach out to me via the email I just sent you. I have been working in our lab and with our designers to get you a solution. We have not observed the phenomenon that you have been experiencing but I would be glad to continue debugging with you as I have been.

    Regards,

    -Adam