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TMS320F280049C: VDDA, VDD, VDDIO, VDDIO_SW are easily burn down when test connection using CCS

Part Number: TMS320F280049C

Hi, Team

      I'm using TMS280049C, and designed a sch/PCB, when I test the connection with MCU using XDS110USB, the VDDA, VDD, VDDIO, VDDIO_SW pins are easily burn down, I followed the Lauchpad design tips, right now I can't figure out what's wrong with my sch/PCB, could you help me to check below?

Thank you

  • Sorry, I do not understand. What does " burn down " mean?

    What voltages are you seeing on VDDA, VDD, VDDIO, VDDIO_SW?

    What voltage are you providing to your device, do you have an LDO or switching power supply circuit? If so please include an image of that as well.

    regards,
    Cody 

  • user5852322 said:
    when I test the connection with MCU using XDS110USB,

    It would seem there is some kind of +3v3 isolation issue between JTAG and x49c MCU? I never power MCU via XDS probe +3v3 source or common with VDD other than ground being common. The posted schematic does not show XDS110 +3v3 power source going to the JTAG 10 pin header, via the ribbon cable to MCU. 

  • Hi, engineer

          I found the problem, I used a kind of scaling powder which was  a little electric-conductive, no spark on the power pin any more after clean it.

          Thank you so much.

          But  I also come across a new problem. the MCU Oscilator sometimes can't oscillate, and the program stops at  function: static void PollX1Counter(void), which is a PollX1Counter, at the same time, the supply current is only 1mA, why? I changed a new F280049C, it works well, and the consumption current will be 5mA. I don't think it is ESD damage, why PLL fail to oscillate?

           Thank you for your kindly reply.

    Best regards

    Gao

  • Hi, Engineers

          I found the problem, the trace of the oscillator is too long, and when I select the internal oscillator, the PLL works well, thank you.

         so the problems are solved, you can close this topic.

    Best regards,

    Gao

  • Gao,

    you have also connected XRSn to pin 2 of the TI14 pin JTAG header. That location is for TRSTn, these pins are very different. Please review the device documentation, remove this connection and add the correct pull resistors to XRSn.

    Regards,
    Cody 

  • Hi, Cody

          Thank you. now it's done.

    Best regards,

    Gao