LM2587: LM2587SX-ADJ/NOPB--No Fuction issue

Ning Li

Part Number: LM2587

Customer Zhejiang Lancoo feedback that they receive LM2587SX-ADJ/NOPB 1000PCS, batch number: 1058381EM1, DC: 2108+5. During the process of using this batch of regulator tubes, it was found that the color of the device pins changed from silver to gold (pls find below) The device pins shows Gold is 3PCS，2 PCS output fuction abnormal，1PCS bruned.

Pls help to check why the device pin color change from silver to gold.

（艾睿）TI LM2587SX-ADJ稳压管异常反馈联络函（20220609）.pdf

over 1 year ago

0 Brigitte over 1 year ago

TI__Guru 59605 points

Hello Ning,

From where did they receive this batch?

Best regards,
Brigitte

0 Ning Li over 1 year ago

Intellectual 590 points

Hi Brigitte,

Arrow.

Thanks

0 Brigitte over 1 year ago in reply to Ning Li

TI__Guru 59605 points

Hello Ning,

According to this thread, sometimes after reflow dis-coloring can happen, see here:

LM3940: Discoloration of component leads after reflow process (original: silver color - after reflow: yellowish color ) - remark: only this component has this failure - WHY? Any reliability concern? - Power management forum - Power management - TI E2E support forums

LM2587sx-adj-nobp uses a similar leadframe material, see here: Material content search | Texas Instruments (ti.com)

I do not know if this is the case here.

If the customer wants to get further details on the possible root cause of the damage you mention, I recommend to start a failure analysis, but this has to go through Arrow as the devices were bought there.

Best regards,
Brigitte