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SN74AVC4T774: PCN for the updated footprint

Danilo A.
Mastermind 30190 points
Part Number: SN74AVC4T774
Other Parts Discussed in Thread: TMUX1111

Hi Team,

Can you please help us with this concern of our customer.

Regarding the differences in Recommended layout diagram for the following parts :

The parts are available in 16 PIN QFN . Datasheets attached for your reference. 

SN74AVC4T774RSV (Jan 2015) 

ti_sn74avc4t774.pdf

TMUX1112RSV (Aug 2019)

ti_tmux1111_12_13.pdf

Issue :

Layout recommendation for SN74AVC4T774RSV , where lead span is 1.55x2.35

Layout recommendation for TMUX1112RSV, where lead span is 1.60x2.40

Do you recommend to update the footprint to lead span of 1.60x2.40 for all the similar package parts that are in our library ??

Layout engineers here feel to increase this pitch to avoid short between corner pins and avoid solder bridge issues… What your thoughts on this ?

I noticed that the latest datasheet of SN74AVC4T774RSV recommended the RSV0016A footprint as shown at page 34 in the link below. This update is not included in the revision history of the datasheet. Our customer would like to know if there was a PCN issued on this change. 

https://www.ti.com/lit/ds/symlink/sn74avc4t774.pdf#page=34

Regards,

Danilo

  • 0
    TI__Intellectual 1450 points

    Hi Danilo,

    Yes footprint to lead span of 1.60x2.40 is recommended which is on the latest version of the datasheet. There was not a PCN issued because packaging/board layout related updates are automated for the datasheet. 

    Best,

    Swathi

  • 0 in reply to Swathi D
    TI__Mastermind 30190 points

    Hi Swathi,

    Thank you for your response. Please see the follow up question of our customer.

    When you say “Automated” , no one verifies or updates are done without a rationale?

    Regards,

    Danilo

  • +1 in reply to Danilo A.
    TI__Intellectual 1450 points

    Hi Danilo,

    There is a separate packaging team who make revisions to the packaging/board layout info and the product line does not get notifications for those changes. The product line is responsible for any changes upto Pg 21 of SN74AVC4T774RSV. Every page after Pg 21, the packaging team is responsible for and they upload packaging/board layout info pages to an internal system. Based on the OPN on our datasheet, the system looks for & pulls respective packaging/board layout pages & appends it to our datasheet. That is what I meant by "automated." Apologies for any confusion.

    Best,

    Swathi