• State Resolved
  • Locked Locked
  • Replies 10 replies
  • Subscribers 80 subscribers
  • Views 954 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.

MSP430FR5994: Landing Pad recommendations for the 80 pin LQFP

James Nadir
Expert 1120 points
Part Number: MSP430FR5994

I found documentation in the datasheet on the mechanical packages. There is some layout footprint documentation on the 64 pin PQFP (don't know if that's the same as the LQFP)  but not patterns for the 80 pin parts (assuming they're different). The layout pcb pattern I need is for the LQFP 12x12. Searching TI's website didn't help - 

  • 0
    TI__Genius 13215 points

    Hi James,

    You could download the package file, which including LQFP 80 pins, on the product page of device:

    http://www.ti.com/product/MSP430FR5994/pinout-quality

  • 0 in reply to Wei.Jetim Zhao
    Expert 1120 points

    thanks for the response. I already examined the CAD files your link points to. Those files describe the package dimensions and do not provide a recommended pcb footprint. In the end I downloaded the Gerber files for the launchpad MSP430FR5994 and measured the footprint's pad dimensions.  

    The mechanical cad file for the PN (S-PQFP-G80) specifies that a pin width is between 0.17mm and 0,27mm and its length which contacts the pcb is between 0.75mm and 0.45mm. Had I used those dimensions my footprint would have been 1mm x 0.3mm. In contrast I measured 1.3mm x 03mm from the Gerbers. The Gerber pads are about 30% longer than what I would have guessed at using the mechanical data. In addition, the file is labeled as Plastic Quad Flatback PN (S-PQFP-G80) no where is it mentioned that this is the same as the LQFP. So more confusion. 

    I don't know why TI is unable to provide a recommended landing pad for the LQFP 80. It is very sad that this information is so hard to find.  Perhaps you can raise this issue to someone at TI responsible for their MSP430 family. Maybe someone there has a recommended footprint for the LQFP they would like to share.

  • 0 in reply to Wei.Jetim Zhao
    Expert 1120 points

    thanks for the response. I already examined the CAD files your link points to. Those files describe the package dimensions and do not provide a recommended pcb footprint. In the end I downloaded the Gerber files for the launchpad MSP430FR5994 and measured the footprint's pad dimensions.  

    The mechanical cad file for the PN (S-PQFP-G80) specifies that a pin width is between 0.17mm and 0,27mm and its length which contacts the pcb is between 0.75mm and 0.45mm. Had I used those dimensions my footprint would have been 1mm x 0.3mm. In contrast I measured 1.3mm x 03mm from the Gerbers. The Gerber pads are about 30% longer than what I would have guessed at using the mechanical data. In addition, the file is labeled as Plastic Quad Flatback PN (S-PQFP-G80) no where is it mentioned that this is the same as the LQFP. So more confusion. 

    I don't know why TI is unable to provide a recommended landing pad for the LQFP 80. It is very sad that this information is so hard to find.  Perhaps you can raise this issue to someone at TI responsible for their MSP430 family. Maybe someone there has a recommended footprint for the LQFP they would like to share.

  • 0 in reply to James Nadir
    TI__Genius 13215 points

    Hi James,

    You should use the Ultra Librarian software to export the PCB footprints and schematic for your design tools format from the downloaded .bxl file of LQFP(PN) | 80. I tried it for my Altium Designer 18 and it works well.

  • 0 in reply to Wei.Jetim Zhao
    Expert 1120 points

    I already tried that. UltraLibrarian does not support my CAD tool. I exported the DFX and used DWG to measure the pads. The DFX files were dimensionless. If I assume that the dimensions are mils then the width of the pad is 0.35mm x 1.00mm which left 0.14mm spacing between the pads (about 5.5mil spacing).  I was expecting the typical 6mils, so I either measured something else or my assumption of the dimension unit was wrong. 

    In the end, I just downloaded the Gerbers for the Launchpad and measured the pads. Those measurements said that the pads are 0.3mm x 1.6mm, much more believable. 

    (warning recreational griping ahead):

    This is a lot of trouble for customers who just wanted to search the pad library of their CAD tool for a matching footprint. In my opinion this should information should be part of the datasheet instead of requiring users to download UltraLibrarian (about 2Gb of disk space and comes with an  annoying upgrade nag screen to pay for an upgrade).   Most CAD tools come with pre-made library footprints so why do I have to use UltraLibrarian to get a footprint when I can just look it up? And why should I have to learn another tool chain ecosystem for information that should be part of the datasheet? If the footprint was completely different standard then yeah maybe but this is not the case with this LQFP. And why does TI make customers go through their "Where's Waldo" website jungle to find the small print that you circled above in red? 

    You don't have to answer the above, I am just venting  about TI's new one size fits all solution darling. I am using the Gerber dimensions to identify the needed footprint. 

  • 0 in reply to James Nadir
    TI__Genius 16840 points

    Hi James,

    This might help: www.ti.com/lit/pdf/mtqf009

    I don't know why we don't have the footprint recommendation in our datasheet but I'll submit this feedback.

    Regards,

    Luis R

  • 0 in reply to Luis RC
    Expert 1120 points

    Thanks Luis, 

    Your link is the best 80 pin FP recommendation I've seen from TI. .

    Do you know if the TQFP is the same as the LQFP footprint? I downloaded the MSP430FR5994 Gerber files and measured the LQFP footprint at 0.3mm x 1.6mm. The TQFP pad recommendation is 0.3 x 1.5mm (slightly smaller).. 

    While you submit feedback to the datasheet owner perhaps it would be good if TI provided a webpage with links to the recommended landing patterns for all their packages (right now this information is scattered in a "where's waldo" across product pages. 

    thanks

    jim

  • 0 in reply to James Nadir
    TI__Genius 16840 points

    Hi James,

    From what I can see, the dimensions of both packages are pretty much the same, except for their height. I would recommend to go with 1.5mm based on the document and based on what I also measured on my Altium footprint.

    And you provide good feedback. We do have this page showing all the packages but it doesn't seem to include footprint recommendations: http://www.ti.com/support-packaging/packaging-tools/find-packages.html

    I also found SNOA293 which for some reason doesn't include this package.

    And of course, we usually recommend customers to access UltraLibrarian across TI. I understand that this tool doesn't support your CAD tool, but it does solve many of these questions. I have followed up with UltraLibrarian to suggest support for your CAD tool (DipTrace, right?), but it's really up to them.

    In any case, I have submitted your recommendation.

    Regards,

    Luis R

  • 0 in reply to Luis RC
    Expert 1120 points

    Thanks Luis RC

    My search for the LQFP footprint has been going on for awhile and I was up against a deadline to submit the design for a prototype build. . I decided to use the 0.3mm x 1.6mm pad footprint for several reasons. 1) it is the recommend in the datasheet for the 64pin PQFP, 2) slightly larger is "safer" than slightly "smaller" (better to be extra alignment room than less) and 3) the 0.3mm x 1.6mm is the size used on the Gerbers for the 80 part on the launchpad.  

    It's too late to call back the prototype build if the pad size is wrong, I will find out in a week or so after the prototypes are returned. 

    I am closing the post because I don't think TI has a recommended landing pad for their 80 pin LQFP and it is crazy to search for that which doesn't exist. 

    I do appreciate your help.

    thank you

    jim

  • 0 in reply to James Nadir
    TI__Genius 16840 points

    I don't think there should be any issue with your implementation, but feel free to let us know once you get prototypes.

    Regards,

    Luis R

**Attention** This is a public forum