• State TI Thinks Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 355 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DLPC3479: Lower impedance between VDD(C5) and VSS(C4)

Michiaki Tanii
Expert 4640 points
Part Number: DLPC3479

Tool/software:

Hi team,

 

Our customer observed lower impedance device between VDD(C5) and VSS(C4) which is 74.2ohm.

Looking at majority devices, those impedance were 1.059 ohm.

They would like to understand if there is possible that lower impedance device is failure device or not.

Could you kindly share your any insights and comments with us ?

 

Thank you and best regards,

Michiaki Tanii

  • 0
    TI__Guru 54705 points

    Hello Michiaki-san,

    This has been assigned the the expert best able to help you with your inquiry.  Today is a holiday - they should get back to you tomorrow on this.

    Fizix

  • 0 in reply to Fizix
    TI__Genius 12015 points

    Hello Michiaki-san,

    Thank you for reaching out to us through E2E!

    Could you please confirm that the 1.059 ohm is the actual resistance, I'm thinking this should be 1.059 Kohm?

    When measuring VDD impedance, how are you testing this?

    Best,

    Aaron

  • 0 in reply to Aaron Black
    TI__Expert 4640 points

    HI Aaron,

    1.059 Kohm is correct number. 

    The method of test is

    • Measured +1.1V line on their custom board. And customer observed 70ohm impedance with suspicious device. (Majority : 300 ohm)
    • Measured the impedance between C5(core 1.1V) and C4(GND) and the impedance was 74.2 ohm (Majority 1.059k ohm)

    Please let me know what you would like to make sure on the testing method.

    Best regards,

    Michiaki Tanii

  • 0 in reply to Michiaki Tanii
    TI__Genius 12015 points

    Hello Michiaki-san,

    Thank you for confirming this! We've got a few follow-up questions for you:

    1. Is this combination still operating correctly as a solution?

    2. To isolate this issue to just the board/controller combination... In your first measurement is this (Majority : 300 ohm) a single customer board compared to a sample of customer boards being tested the same way?

    3. To isolate the controller being the issue... after removing the controller from the board, does this impedance from C4 - C5 follow the controller?

    Best,

    Aaron

  • 0 in reply to Aaron Black
    TI__Expert 4640 points

    Hi Aaron,

     

    1. Customer hasn’t tested it to see normal operation or not.
    2. Yes. This is single customer board.
    3. Yes. This issue follow the controller.

     

    At first, customer want to know if the lower impedance device has something failure or not. Could you share any insights and comments with us ?

     

    Best regards,

    Michiaki Tanii

  • 0 in reply to Michiaki Tanii
    TI__Genius 12015 points

    Hello Michiaki-san,

    This part indeed seems to be a failure, if you are seeing many of these failures please advise our quality team and we can start investigatory work.

    As a general thought, proper ESD handling should be followed when working with these controllers as they are easily damaged. We try and build in ESD protection structures to mitigate this issue but it cannot always be protected against.

    I hope this helps!

    Best,

    Aaron