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PCA9306: About the recommended PAD shape of the DQER package of PCA9306.

user6365974
Prodigy 190 points
Part Number: PCA9306
Other Parts Discussed in Thread: SN74LVC1G74, SN74AUP2G08, SN74AVC2T244

There is a difference between the content of 2019 (P29) and the content of 2021 (P34).

What is the reason for the change in dimension values?

I will attach the PDF downloaded in 2019.

pca9306.pdf

  • 0
    TI__Mastermind 25165 points

    Takayuki-san,

    I am not sure I understand your question. Documentation changes are shown in the Revision History section of the data sheet.

    Is there a particular set of dimensions or characteristics that you're referencing?

    Best,

    Danny

  • 0 in reply to Danny Bacic
    Prodigy 190 points

    Danny

    thank you for your reply.

    I'm sorry that the writing style is difficult to understand.

    Only the EXAMPLE BOARD LAY OUT parts for 2019 and 2021 are excerpted and attached.

    The dimensions and shape of EXAMPLE BOARD LAYOUT in the DQE package have changed.

    If you have any reason for this change, please let me know.

    pca9306_2019.pdfpca9306_2021.pdf

  • 0 in reply to user6365974
    TI__Mastermind 25165 points

    Takayuki-san,

    Thank you for the clarification. The DQE package has not changed. the example board layout is just an suggestion, not a requirement. The specifications of the device package itself are located on the page prior to the ones you've excerpted above.

    The example board layout is a possible footprint design based on the package, which is drawn in the Package Outline drawing page.

    Changes to the form, fit, or function of a device result in a change notification being sent to customers (described in our Quality Policies and Procedures on ti.com). A package change would be a form change that would result in a notification. This is not the case for the DQE package.

    Best,

    Danny

  • 0 in reply to Danny Bacic
    Prodigy 190 points

    Danny, thank you for your reply.
    In 2019, I made a board using the board layout example of the 2019 data sheet,
    but solder shorts between pads frequently occur at the component mounting stage.
    For this reason, we plan to revise it with the board layout example of the 2021 data sheet.
    I hope that the solder short circuit will be eliminated.

    Is there any information on the board layout example of the 2019 data sheet
    that solder shorts are likely to occur during mounting?

  • 0 in reply to user6365974
    TI__Mastermind 25165 points

    Takayuki-san,

    Thanks for your explanation, I understand.

    Solder shorts during mounting/assembly are heavily process-dependent. Designers generally make routing and footprint sizing decisions based upon the recommendations and requirements of the assembly process. For example, reducing pad sizing for closely-packed surface mount components can reduce risk of shorting.

    The Package Outline drawing is the specification for the part. The Example Board Layout is only an example - not at all a requirement. These layout decisions can be different based upon the needs of the design. The drawings are simply provided as a use case, similar to how Typical Application schematics are just examples of how to use the device, though actual designs might implement it in a different way.

    Hopefully I've been able to help clarify things here.

    Best,

    Danny

  • +1 in reply to Danny Bacic
    Prodigy 190 points

    Danny, thank you for your reply.

    The foot pattern is a suggestion, not a requirement.
    The foot pattern needs to be adjusted depending on the situation.
    I understand that.

    And I'm sorry many times. I will ask you again.
    Please tell us the reason why the following materials have changed. (I just want to know why it changed)
    "SCPS113M-OCTOBER 2004-REVISED APRIL 2019 P29 Figure 4211032 / C 10/12
    SCPS113N – OCTOBER 2004 – REVISED OCTOBER 2021 P34 Figure 4225204 / A 08/2019 ”

  • 0 in reply to user6365974
    TI__Mastermind 25165 points

    Takayuki-san,

    Texas Instruments regularly maintains and upkeeps documentation to ensure they are up-to-date. The DQE package was created decades ago, and since that time, our documentation system has become enhanced and digitized. This package is not unique to the PCA9306 - it is used by numerous devices across TI.

    For every device in the DQE package, this packaging addendum (DQE0008A) is included automatically in the data sheet. For example, see SN74LVC1G74, SN74AUP2G08, or SN74AVC2T244. Note that the same packaging addendum is automatically included. In some cases (e.g. SN74AUP2G08), the packaging addendum is newer than the data sheet (2019 vs. 2010). This is why the updated package example layout is unrelated to the data sheet update from SCPS113M to SCPS113N.

    As package information is digitized, our packaging team takes every opportunity to design example layouts based on what is generally seen in the industry. The new example layout was not created due to any error or issue with the previous layout example.

    Best,

    Danny

  • 0 in reply to Danny Bacic
    Prodigy 190 points

    Danny
    thank you for your reply.

    Now that I understand the situation, I will close this matter.
    Thank you very much.