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LM2676: lead is without plating for the part of LM2676S-ADJ/NOPB

Jason Wei
Prodigy 70 points
Part Number: LM2676

Hello,

In Feb of this year, we received 100pcs LM2676S-ADJ/NOPB from Mouser. Now, we got customer feedback that this part should have tin plated leads as per data sheet but the actual parts are without plating.the lead color is golden(see attached picture). Pls help to confirm what's the reason for this issue. Now, our customer is waiting reply from us. pls help to give us reply as soon as possible. thanks.

The batch number of these 100pcs is below

1736+5

7389253EM7

1744+5

7439679EM7

  • 0
    TI__Mastermind 23845 points
    Hi Jason,

    I am not sure yet at this moment. Please allow some time for answers.

    Thanks
    -Arief
  • 0 in reply to Arief Hernadi
    Prodigy 70 points
    Hello,
    Our customer is waiting reply from us , pls help to give us answer as soon as possible.
    Rgs!
    Jason
    2018/7/5
  • 0 in reply to Jason Wei
    Prodigy 70 points
    Hello,
    Our customer also want to know whether it(without plating) will lead to latent failure like corrosion on the component if used under different climatic condition on field.
    Rgs!
    Jason Wei
    2018.7.5
  • 0 in reply to Jason Wei
    TI__Guru 68085 points
    I will send this to the product engineers.
  • 0 in reply to Frank De Stasi
    Prodigy 70 points

    Hello,

    Thanks, but I need get answer as soon as possible because our customer is chasing us to get answer.

    From your specification, this part should be with tin plating lead. If it has the possible this part is not LM2676S-ADJ/NOPB and it is LM2676S-ADJ because these two different parts are with same marking. How about the lead plating for  LM2676S-ADJ

    Rgs!

    jason Wei

    2018.7.6

  • 0 in reply to Jason Wei
    TI__Guru 68085 points

    Here is the response from our package group:

    This is with Sn plated parts. Does the customer only see this after reflow or fresh units also exhibit the same so called “discoloration”?

    If prior SMT, I suggest to further investigate with EDX/cross section of the samples to check on any contaminants and Sn thickness.

    If after SMT, we may ask the condition of reflow as well as any N2 supplied during the reflow process.

    Please see the above question.

    I will pass you question back.

     

  • 0 in reply to Frank De Stasi
    Prodigy 70 points

    Hello Frank,

    For this issue, it is after reflow. Today it was confirmed by us. For this part of LM2676S-ADJ/NOPB, we still have some stock and they are from our other supplier. and they are no problem and they are with tin plating lead. Today we test some pcs in same reflow profile. The same issue was found after reflow.Currently there is no N2 supplied during our reflow process. Today it was also verified by us, if we supply N2 during the reflow process, the issue will be disappeared.

    Below is our reflow profile.

    Here, I want to know if we must need supply N2 during the reflow process for your part? Where it was specified this? As if I cannot find this requirement in your datasheet. As you know if we supplier N2 during the reflow process, the cost will be increased. Normally we will not supply N2.

    From my point of view, I think your tin plating cannot bear high temperature, we also used some other parts with tin plating lead, we never find such issue.

    Others, for this discoloration issue, whether it will affect part function or reliability in future? 

    Rgs!

    jason Wei

    2018.7.9

  • 0 in reply to Jason Wei
    TI__Guru 68085 points
    If you can send your email adress to simpleswitchereapps@ti.com I will
    get you in contact with our package engineer.
  • 0 in reply to Frank De Stasi
    Prodigy 70 points

    Hello,

    My mail address is jason.wei@enics.com

     

    Rgs!

    Jason Wei

  • 0 in reply to Jason Wei
    Prodigy 70 points
    Hello,

    I sent mail to the address of simpleswitchereapps@ti.com , but got sending failure information from mail system.
    Today, we have done further investigation for this issue, we can see tin plating after we scraped off the golden layer. so this issue is only tin plating surface is discoloration after reflow process.
    So, I want to know what's the reason for this case? How we can improve this issue except supply N2 during reflow process?
    For this case, if it will affect part function or reliability in future or if it will lead to latent failure like corrosion on the component if used under different climatic condition on field? We want to get answer for this question because some PCBA with this issue have been shipped to customer, customer is chasing us for this.
    Hope you can give us reply as soon as possible!

    Rgs!
    Jason Wei
    2018.7.10