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TLV62595: Damage problem

Rhea Gao
Expert 2290 points
Part Number: TLV62595

Hi，

I have a customer who uses TLV62595. TLV62595 is currently used in two projects, namely TPS54360BDDAR+TLV62595; TPS54527DDAR+TLV62595.However, 10pcs were found to be defective.

Application: TLV62595 is 5V input, 0.92V output.  The fault phenomena are: 5V input short circuit, no output, output impedance is incorrect.   The two items of the former level TPS54360BDDAR, TPS54527DDAR are output 5V.    They all tested fine and had multiple DCCS on the back end, like TLV62569DBV, only the TLV62595 was broken.

Attached are the related schematic diagram and PCB screenshot.   Please help to review and suggest where the problem is.

   2287.TPS54360BDDAR+TLV62595.zip           2352.TPS54527DDAR+TLV62595.zip

Thanks!

  • 0
    TI__Expert 8756 points

    Hi Rhea,

    I will check the schematic and get back to you later today.

    Best regards

    Sneha 

  • 0 in reply to Sneha
    TI__Expert 8756 points

    Hi Rhea,

    I reviewed the schematic and PCB for TLV62595. Please see below for my comments:

    1) The schematic looks okay. However, I could not find the datasheet for SMPC0420HP-R47M. Could you please share? I also see a ferrite bead at the output, I would recommend to ensure that it does not affect the loop stability of the application. 

    2) The placement of components looks okay in the 2287 file. For 2352 file, the placement ofinput capacitor and inductor looks little bit far from the IC. 

    Can you share how does the copper planes look like in the layout? 

    3) One possibility to trigger such device failure could be an overstress at the pins of the IC exceeding the ABS max rating of the device. To verify this, please share the waveforms of Vin, SW, Vout and Inductor current at steadystate, startup and shutdown conditions.

    4) What is the load to TLV62595 in both projects?

    5) What is the power supply to the pre-regulator? 

    6) What is the end application?

    Thanks!

    Best regards

    Sneha 

  • 0 in reply to Sneha
    Expert 2290 points

    Hi Sneha,

    Sneha said:
    ) The schematic looks okay. However, I could not find the datasheet for SMPC0420HP-R47M. Could you please share? I also see a ferrite bead at the output, I would recommend to ensure that it does not affect the loop stability of the application. 

    The data manual for SMPC0420HP-R47M is attached.

    Sneha said:
    2) The placement of components looks okay in the 2287 file. For 2352 file, the placement ofinput capacitor and inductor looks little bit far from the IC. 

    The customer has not provided it yet.

    Sneha said:
    3) One possibility to trigger such device failure could be an overstress at the pins of the IC exceeding the ABS max rating of the device. To verify this, please share the waveforms of Vin, SW, Vout and Inductor current at steadystate, startup and shutdown conditions.

    Refer to the waveform diagram in the attached document,

    Sneha said:

    4) What is the load to TLV62595 in both projects?

    The load of TL62595 ranges from 1.7A to 2.8A, which varies according to the changes in the upper layer app business processing of the final product.

    Sneha said:
    5) What is the power supply to the pre-regulator? 

    I don't understand the definition of a pre regulator.

    The customer's circuit board is a 12V DC input with an external AC-DC 12V 3A power adapter. The TPS54360BDDAR on the board is loaded at 12V and turned out at 5V. TLV62595 is responsible for converting 5V to 0.92V.

    Sneha said:
    6) What is the end application?

    TLV62595 has a load of 5V to 0.92V, and the load terminal is the Vcore of our CPU. When used as the final product, the Vcore current varies from 1.7A to 2.8A.

    SMPC0420HP-R47M.pdfTLV62595 waveforms_20240425.docx

    Thanks for your support!   

  • 0 in reply to Rhea Gao
    TI__Expert 8756 points

    Hi Rhea,

    I will get back to you tomorrow.

    Best regards

    Sneha

  • 0 in reply to Sneha
    TI__Expert 8756 points

    Hi Rhea,

    I do not see any concern with the inductor used. 

    I also do not see any overvoltage event in the waveforms you shared. However, In my opinion, there are possibilities of overvoltage exceeding abs max rating of device, if there are any fast transients at the Ac line, which could then overstress the device input. 

    I would suggest to check the customer board supplied with the adapter and do several turn on and off cycles and verify all the voltages (Vin, SW, Vout and IL).

    Could you also please elaborate this? 

    Rhea Gao said:
    which varies according to the changes in the upper layer app business processing of the final product.

    And your end application is CPU, right?

    Thanks!

    Best regards

    Sneha