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TAS6424L-Q1: TAS6424 burning out in-field

Tom G.
Prodigy 50 points
Part Number: TAS6424L-Q1
Other Parts Discussed in Thread: TAS6424

Hi there,

I'm running into issues where my product is failing in-field and upon inspection, we notice that the TAS6424 chip is burnt on the PVDD (24V) rails on our board (attached). We have several TAS6424 chips sharing a common PVDD rail and when this issue occurs it only affects one and the effect propagates upstream and burns out a 5V regular.

Could someone help me make sense of why this might be happening? Anyone had any similar experiences?

Thanks in advance,

Yutong

  • 0
    TI__Mastermind 35740 points

    Hi Yutong

       From the picture, seems all the PVDD pins has obvious burns. It is the failure behavior when FET side got damaged. And most of the time, it's the PVDD power supply decoupling possibly lead to this failure. 

      On this board, at the right middle side, there's another group of PVDD pins, but on Top layer there's not decoupling cap, maybe put them at the back side. At least 100nF need to be put at the Top side, it's quite important to remove ripple on the PVDD. 

       At the right top side, the decoupling cap also the vias could be put more close to the device. Both PVDD and GND of the cap should have more vias.

       And I didn't find electrolytic capacitor in the picture, could you please confirm where is the location? It's also important to put close to the device.

      How many failure unit have we found for now? We could use oscilloscope to capture the OUT to GND, and PVDD to GND waveform, to check how much is the ripple when output highest power. Remember to use ground ring on the probe, and test close to the device's pin. 

  • 0 in reply to Shadow He
    Prodigy 50 points

    Thanks for writing back. I'm happy to share more details but I would prefer to share this privately. Is there anyone we can talk to directly about this?

  • 0 in reply to Tom G.
    TI__Mastermind 35740 points

    Hi Yutong

      Sure, you could e-mail to shadow-he@ti.com, and derek-gong@ti.com. 

  • 0 in reply to Shadow He
    Prodigy 50 points

    Thanks! I wrote an email to the two of you. I look forward to continuing our conversation.