• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 62 subscribers
  • Views 2502 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

Pin orientation in land pattern LP38500-ADJ

Imon Mondal
Prodigy 30 points
Other Parts Discussed in Thread: LP38500-ADJ

Hi,

I am using the LDO,  LP38500-adj, WSON package. The following the link to its datasheet.

http://www.ti.com/lit/ds/symlink/lp38500-adj.pdf

The land pattern of the WSON package (NGS008C), shows  the pin orientation as clockwise from 1-8. However, in the packaged chip I found it to be anti clock wise from 1-8. This creates a problem when I am trying to fit the chip in my board footprint.  Am I missing something, or there is some caveat. 

Please advice.

-Thanks and Regards

Imon

  • 0
    TI__Mastermind 22610 points

    "...The land pattern of the WSON package (NGS008C), shows  the pin orientation as clockwise from 1-8 ..."

    I''m confused ...

    The recommended land pattern for the WSON NGS0008C in the LP38500 datasheet does not show any pin assignment or pin orientation. The land pattern is symmetrical, so pin #1 could be either at the top/right or the bottom/left.

  • 0
    TI__Mastermind 22610 points

    Looking at this some more, only the package bottom view has pin #'s assigned.

    The pin numbers and pin orientation there are correct when you are looking directly at the bottom of the package, but need to be ~mirrored~ when the package is flipped over and the leads are facing down.

    The 'Connection Diagrams for WSON Package' (Figures 5 and 6 on Page 3) are both "Top View", so that's an x-ray view looking through the top of the package.

  • 0 in reply to Donald Jones
    Prodigy 30 points

    Hi Donald,

    Thanks for your reply. I am a bit confused, since it is nowhere mentioned that it is the package bottom view where pin number has been assigned.  I assumed it to be the pin assignments of the land pattern itself.

    -Imon

  • 0 in reply to Imon Mondal
    Prodigy 30 points

    A case in point is another LDO, TPS77050.

    http://www.ti.com/lit/ds/symlink/tps77050.pdf 

    Its footprint matches with the top view as it is. No mirroring is required.  This is where it gets confusing, when one the convention changes from one datasheet to another without any mention of it.

    -Regards

    Imon

  • 0 in reply to Imon Mondal
    TI__Mastermind 22610 points

    I agree that it is confusing.

    For  the SOT-23 (DBV) package with TPS77050 all of the leads are visible from the top-side view, so there is no need to show bottom view. So, there is no no mirroring of pin #'s assigned on a bottom-view required.

    No so for WSON where the leads are not visible from the top-side view. This is usually resolved in one of two ways: 1) reveal the hidden leads with dashed lines on the top-side view; 2) show the leads directly via a bottom-view.

    Same as the WSON land-pattern, the DBV land-pattern does not show pins #'s.