• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 46 subscribers
  • Views 541 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.

mr-QFN manufacturing Stencil (DAC3482)

Johann Gerber
Prodigy 60 points
Other Parts Discussed in Thread: DAC3482

Hi there,

We are using the DAC3482 mr-QFN 88 in our design.  The first development boards we did, we did not pay that much attention to the details

of the footprint recommendation and did not have as many vias and they were bigger than recommended.  The result - not all the pins made contact with the board

and some boards were not useable.

With the design update, we followed the recommendations (SLAA493) to the T, including making the solder paste stencil slightly bigger than the solder mask clearance on the smaller pads.  Now we have even more problems and may have to scrap our pre-production run.  We are still trying to find out what exactly is wrong, but it looks like we have too much solder.

The layout & stencil recommendations do not stipulate the stencil thickness that they apply to.  Could you forward me more details on the stencil thickness and is it possible to get more support with our design?

Thanks,

Johann

  • 0
    TI__Guru* 78324 points

    Hi Johann,

    As of last year, we have removed the app note SLAA493 from the web and have updated with a new app note regarding the mrQFN package stencil design and assembly recommendations. Please see the app note link below for detail:

    http://www.ti.com/litv/pdf/szza059

    This app note should cover everything you need for the mrQFN design. If you have any further questions, we can loop in our packaging team to help answer your questions.

    -KH

  • 0 in reply to Kang Hsia
    Prodigy 60 points

    Hi Kang Hsia,

    I looked at the App note and it has much more detail.  A have the following uncertainty:

    The example is done for the 100 pin MRQFN package, but I am unable to find it on TI's web site.  I can therefor

    not say if differences are is a recommendation change or a difference between the 88 and 100 pin package w.r.t. the size of the corner pad

    and the spacing of the centre row.

    From SCBA017D, page 26 it would seem that the 100 pin package and that I should still use the recommendation as done on the old App note.

    Could you confirm?

    Thanks,

    J

  • 0 in reply to Johann Gerber
    Prodigy 60 points

    Oi! - My mistake.  I should have looked at the end of the app note.

    Sorry,

    J