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TPS563219A: cannot work well sometimes, output volatge will be abnormal.

hua.jing
Prodigy 10 points
Part Number: TPS563219A

Our design can be seen below.

We find that some PCBA has problems that there is no 3.3V output, the output wave can be seen below. Sometimes, reboot the machine can recovery. 

If we remove one Cout 22uF, the issue disappear, but we can confirm Cout in our deisgn is between 20uF-68uF as datasheet.

In our design, we use 4.7uH, the Max as datasheet describes. The TYP value is 2.2uH.

Can you please help check if the inductor 4.7uH is OK nor not? And could you please give us some suggestions how to solve this issue?  It seems it isn't the root casue that just remove one 22uF Cout.

  • 0
    TI__Expert 8100 points

    Hi Hua,

    The overall design looks well from schematic. LC parameters are within range of recommended LC table in ds.

    From shown waveform, it is quite hard to decide what causes such oscillation. Please help to capture SW+IL+Vout+PG and measure time of each oscillation period in Vout waveform.

    BTW, could you please help to share layout as well?

    BRs

    Zixu