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TPS650061: TPS650061RUK Technical Support Request

TI-CSC
Genius 11270 points
Part Number: TPS650061

Hello E2E Experts,

Good day.

TPS650061RUK Technical support request

I am inquiring about the TPS650061RUK output voltage we purchased.

There is an issue with output voltage among optical communication production boards as below, so please check it.

Photo 1 TPS650061RUK All Output Voltage Normal Operation (Digital scope measurement)

Photo 2 TPS650061RUK 3.3V output voltage output abnormally.

Photo 1 shows that the TPS650061RUK output normally and Photo 2 shows that it is output abnormally.

From the figure above, you can see that it is caused by the influence of 5V (yellow line in the figure) entering the TPS650061RUK.

I want to know exactly what the problem is and the cause of the problem with the output of the TPS650061RUK. (For example, 5V ramp time, ripple.

Correct:

Wrong:

Regards,

CSC

  • 0
    TI__Mastermind 41481 points

    Hi CSC,

      Before answer your questions, please provide information below:

    1. Did you capture both photo 1&2 from same board?
    2. How did you apply the 5V Vin?
    3. Can you share the schematics for the application?
    4. From photo 2, how can you get the LDO output 1.8V level (purple line) from an input (red line) lower than 1.8V?

    Thanks!

    Phil

  • 0 in reply to Phil Yi40
    TI__Genius 11270 points

    Hello Phil,

    Good day.

    1. Did you capture both photos 1&2 from the same board?
    >>I used the same board.
     
    2. How did you apply 5V Vin?
    >>Two types of SMPS (Switching Mode Power Supply) were used.
     
    3.Can you share the schematics for the application?
    >>See attached file.
     
    4. From photo 2, how can you get the LDO output 1.8V level (purple line) from an input (red line) lower than 1.8V?
    >>I don't understand the question. The picture below is a picture of accepting 1.8V with a digital scope after applying 5V to the TPS650061RUK.
    >>The position of the measuring probe is indicated in the attached file, but please refer to it later.
    Regards,
    CSC
  • 0 in reply to TI-CSC
    TI__Mastermind 41481 points

    Hi CSC,

      The schematics tell the details now, but I can't find any issue with it besides of the naming issue of pin17; it should be named "VLDO2".

      Can you try a few more boards? if the same issue happens to all boards you test, then we may need to do post-production FA.

    Thanks!

    Phil

  • 0 in reply to Phil Yi40
    TI__Genius 11270 points

    Hello Phil,

    I'm sending you the quantity of production and the number of defects.
     
    Total production quantity: 87 PCS
     
    Number of defects: 5PCS
     
    Defect rate: 5.7%
    I use two types of SMPS.
     
    It's 5V.
     
     FIGURE1 is operating normally
    FIGURE2 is an abnormal operation
    I use 5V, 3.3V, and 1.8V.
     
     3.3V is not output.
     
    Depending on the generation of SMPS,
     
    3.3V not coming out
     
     I don't think it's the part itself.
     
    Please ask us to check the reason why it appears depending on the SMPS power supply environment.
     
    You guys use it in this environment, so this is the case.
     
    It should be used in an environment.
     
    Wanting such an answer.
     
    Guidelines that may arise from any environment or any external factors are requested.
    Regards,
    CSC

  • 0 in reply to TI-CSC
    TI__Mastermind 41481 points

    Hi CSC,

      The device is a legacy part with limit support; I'm still waiting for help from someone who has some experience with the device; also, I just ordered an EVM trying to duplicate the issue you're seeing.

      I'll let you know as soon as I get any result either from someone or from my lab test. 

    Thanks!

    Phil

      

  • 0 in reply to Phil Yi40
    TI__Mastermind 41481 points

    Hi CSC,

      I got the EVM delivered today and tested many times with 2 different 5Vin ramp-up time applied as showing by pictures; I don't see the same issue you reported. 

      I have following suggestions:

    1.  Send me a board with the issue; I'll debug on it.
    2.  Report the failure to your local TI sale for a post-production FA.

    Thanks!

    Phil