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LT8620 Don't WORK

Hi,

We use LT8620 Byck converter one of our design. Input : 24VDC, Output:3.3V @1A 

When I powered from 12V adaptor to Chip Power input, Chip doesn't poroduce 3.3V. Just only working INTvcc regulator. (I can measure 3V3 from INTVCC)
I disasssambled chip and assamble new LT8620 and working correctly. Two of this chip LOT Number is Different!!

Fault Chip LOT Number :  8L24 (Production Date January 2018) - Top Marking of the chip

Working Chip LOT Number :  9A04 (Production Date January 2019) - Top Marking of the chip

What is the problem for this LOT Number producton? Can you examine this LOT number production and give us any suggestion, please?

Best regards,

İSMAİL TAŞDEMİR

Hardware Design Engineer

Parents
  • All IC production lots are tested before release. It is highly unlikely that an IC goes out with issue.

    If you think that this is an IC issue, please contact local ADI sales or FAE to submit the failed sample for failure analysis.

  • We have the SAME problem.
    Fault Chip LOT Number : 9D07, 8A32...and more. Working Chip LOT Number : 0A42 .
    I sent some emails to CIC.Americas@analog.com who tried to help me but to no avail.
    If you think you should, ask him to forward the emails we exchanged where I inform him
    in detail about all the tests I got (but I'm still trying. I'll check it out with an x-ray).
    I inform you that the circuit is EXACTLY THE SAME as your datasheet.
    We have no alternative but to return thousands of parts to our supplier.
    If you think you should, I suggest informing your factories as it is a serious
    problem that causes us disturbances.


  • Hi LucianoSV,

    If you think there is issue related to quality, best to reach out to local ADI representative to channel your concerns or to the point of purchase of parts. There should be workaround to address concerns.

    You have my email address through private message. I can take a look at your communication with CAC and see how to move forward from there. I don't want to jump to conclusion without properly understanding all details.

  • Mr moderator do not publish this post or delete it!. Just let me know if it's possible to change my nickname to something like __LLR__ and change it for me. Send me a private message. (yes I can edit!)  By the way, I already thanked my friend FIL for a private message. Thank you again Fil !!.Slight smile
  • Interesting. We also have problems.

    Top side marking: 9C38 works 100% perfect

    Top side marking: 8J69 does not work. However, it has correct VCCINT, SS 2uA is OK and it makes a few switching cycles but quits switching after that. Tested everything in order to try and establish if we have borderline design issues, different bootstrap cap, pulled EN directly to VIN, tested different FB resistor values etc. etc. Nothing help, it behaves in same way. 

    If we switch part to 9C38 all is working 100% perfect, no other changes. Tested on several boards and all works with 9C38 marked part.

    Since this is a low volume production batch, only 100pcs - but a very premium product - I cant say where we bought the 8J69 parts from, probably one of the catalogue dsitributors. 

    If you have gained any more insigned in your case, feel free to share. 

    Thanks,

    Martin Voss

    Sweden

Reply
  • Interesting. We also have problems.

    Top side marking: 9C38 works 100% perfect

    Top side marking: 8J69 does not work. However, it has correct VCCINT, SS 2uA is OK and it makes a few switching cycles but quits switching after that. Tested everything in order to try and establish if we have borderline design issues, different bootstrap cap, pulled EN directly to VIN, tested different FB resistor values etc. etc. Nothing help, it behaves in same way. 

    If we switch part to 9C38 all is working 100% perfect, no other changes. Tested on several boards and all works with 9C38 marked part.

    Since this is a low volume production batch, only 100pcs - but a very premium product - I cant say where we bought the 8J69 parts from, probably one of the catalogue dsitributors. 

    If you have gained any more insigned in your case, feel free to share. 

    Thanks,

    Martin Voss

    Sweden

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