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SN74LS157: Solder Heat Flow condition of "265C 8sec"

Tahara
Prodigy 250 points
Part Number: SN74LS157
Other Parts Discussed in Thread: CD4002B

Tool/software:

MSL for SN74LS157N (DIP) is N/A in the datasheet though, is it also OK with our customer's required condition of "265deg-C 8s"?

  • 0
    TI__Genius 14691 points

    Hi Tahara,

    At the present time there is not a JEDEC industry standard for recommended soldering profile for through-hole (DIP) packages. TI does perform a Solder Heat test in which the leads of the DIP devices are subjected to 260C solder for 10 seconds to ensure that they can withstand the heat of molten solder.

    There are moisture classification restrictions for peak temperatures and time/temperature targets, all are defined in JDSTD-020.

    With that said, PDIP does not have a MSL rating, just a peak temperature (260C). Best to cautiously follow the JSTD for low MSL rating. There are several variables, so we cannot give a single number. The PCB manufacturer should be able to make the adjustments depending on their flow (hopefully they have a copy of the spec).

    Regards,

    Owen

  • 0 in reply to Owen Westfall
    TI__Prodigy 250 points

    Thank you for your reply.

    We had the comment from Apps team for CD4002B in the other E2E thread though, is your answer for SN74LS157N same as it?

    "TI only guarantees performance under conditions described in the datasheet, but I wouldn't expect this to cause any issues."

  • 0 in reply to Tahara
    TI__Genius 14691 points

    Hi Tahara, 

    Yes my answer is the same. 

    Regards, Owen