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TX7316EVM：Hardware problem

poemling
Prodigy 20 points
Part Number: TX7316EVM


When using TX7316EVM, the ±5V power supply is abnormal. Is a component faulty or the CPLD faulty? How to deal with it? Measurement data are listed in the following file.

7776.data.pdf

  • 0
    TI__Expert 7130 points

    Hi Poemling,

    Thank you for reaching out.

    Let me assign this thread to Savyan, who supports the ultrasound transmitter products of TI. 

    He will get back to you as soon as possible.

    Thanks & regards.

    Abhishek

  • 0
    TI__Intellectual 1790 points

    Hello,

    It looks like the current drawn is higher than expected. From the data shown here, the 1.8V LDO seems to be the defective one. You can confirm that by removing the LDO and checking the +5V supply current and voltage.

    After removing the LDO, check the impedance seen from TP1 to ground. The only component to which the 1.8V is connected is the CPLD. If the impedance is low even after removing the LDO, then the CPLD could have gotten damaged. Otherwise, the 1.8V LDO could be the faulty one.

    Thanks and Regards

    Savyan

  • 0 in reply to Savyan Kanisserry
    Prodigy 20 points

    Hi Savyan,

    After removing the LDO(U1), the impedance seen from TP1 to ground is 0.5 Ω.  At this time, the circuit between the empty pin 5 and empty pin 2 is suspected to be short circuited. The impedance measured between these pins is shown in the picture below.  Is the low impedance from TP1 to ground caused by this short circuit?  Could you help me confirm that the CPLD is damaged?

    Impedance from TP1 to ground: 0.5 Ω   

    Impedance at both ends of R7: 3.38 kΩ    

    Impedance at both ends of R10: 3.38 kΩ

    Thanks and Regards

    Poemling

  • +1 in reply to poemling
    TI__Intellectual 1790 points

    Hi Poemling,

    From the above measurements, it looks like there is short from the TP1 node to ground. There are a few components connected to that node including the CPLD. To confirm that the CPLD has gotten damaged, you will have to remove all the capacitors connected to this node, and re-check the impedance to ground from the TP1 node. If the short is still there, then the CPLD would most likely have gotten damaged.

    Thanks and Regards

    Savyan

  • 0 in reply to Savyan Kanisserry
    Prodigy 20 points

    Hello,

    If I want to replace the damaged CPLD with a new one, which one should I choose? 5M570ZT100A5N or 5M570ZT100C4N? It is 5M570ZT100A5N on the user's guide, but the actual installation on the board is 5M570ZT100C4N.

     

    Thanks and Regards

  • +1 in reply to poemling
    TI__Intellectual 1790 points

    Hello,

    The slight difference in the names are associated with speed and temperature grades. For our application, both of them should work.

    Regards

    Savyan

  • 0 in reply to Savyan Kanisserry
    Prodigy 20 points

    Hello,

    What are the possible causes of CPLD damage? Will the order in which I turn on or turn off the power supplies damage the CPLD?

    Thanks and Regards