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MAX3221: MFR differences

Anthony Sanchez
Prodigy 30 points
Part Number: MAX3221

Hello,

I am looking for some help in determining if there is manufacturing differences between two of the same chips that were ordered at different times.  We have an older version that works with our board, but when we purchased a new set of boards (outsourced board), the new batch has an issue with these MAX3221 and does not function as expected.  

I have debugged the problem and narrowed it down to the MAX3221, in which changing out the component for an older component, the board functions as expected.

The MFR markings are as follows:

Working - "MB3221I 77AG3 P415"

Not working - "MB3221I 24KG4 A38E"

Are these different versions of the MAX3221?  If so, is it possible to order the "Working" chips.  The working chip is from an older board probably about 3 years old compared to the not working chip (<=1 month of having in possession).

Furthermore, if they are different, can you please let us know what the difference is?

Thank you!

Anthony J. Sanchez

  • 0
    Guru 282390 points

    A year ago, production was moved to a new fab with 300 mm wafers. The new die is different, but guarantees the same limits as specified in the datasheet.

    Older chips probably do not exist anymore.

    Switching power supplies are sensitive to board layout. Check that the capacitor traces (especially C1,C2) are as short as possible, and that you are using the capacitor values in figure 9-1.

  • 0 in reply to Clemens Ladisch
    Prodigy 30 points

    Thank you Clemens.  This probably does explain the change in expected operation.  There was a discovered flaw in the design that we got lucky with previous chips.  We have an "OR" trace on the DIN and ROUT traces to the processor which is causing this issue with the new chips and board. 

    Would it be possible to trace the lot code and see if there are any available, or check to see if there are still available chips pre-300mm wafer fab?  This might not be something that can be reached via e2e forum, but if you have a contact I can reach out to, that would be a great help!

  • +1 in reply to Anthony Sanchez
    TI__Guru 70552 points

    Anthony,

    As Clemens said, there likely aren't any older devices available, but you can contact r-sanchez1@ti.com for further information.

    Regards,

    Eric Hackett