LM7800: LM7800

Qiuli Guo

Prodigy 30 points

Part Number: LM7800

Tool/software:

LM7815CT/NOPB Please help to analyze whether it is oxidation and the reason for oxidation

2 months ago

0 Gregory Thompson 2 months ago

TI__Expert 4810 points

Hi Qiuli,

I assume you are referring to the darker discolorations at the edge of the leads, and not the copper color on its side (which it gets from the copper material underneath the tin plating).

Oxidized tin is dark in color and appears to be a possible cause of the discoloration on the top two LDOs. The discoloration on the other ones is likely partially oxidized tin in that case.

What is the concern with oxidization here?

What situations and events have these parts been subject to prior to this photo? Are they opened from a fresh package? Sitting in a drawer? Removed from an active component? Subjected to heat but not soldered? Etc?

Thanks,

Gregory Thompson

0 Qiuli Guo 2 months ago in reply to Gregory Thompson

Prodigy 30 points

Oxidation was found before the goods were used, packaging was not opened,

0 Gregory Thompson 2 months ago in reply to Qiuli Guo

TI__Expert 4810 points

Hi Quili,

Thank you for the information. I've contacted packaging on the and I'll let you know what they say.

Best,

Gregory Thompson

0 Qiuli Guo 1 month ago in reply to Gregory Thompson

Prodigy 30 points

hi Is there any reply plz？

0 Gregory Thompson 1 month ago in reply to Qiuli Guo

TI__Expert 4810 points

Hi Quili,

Thank you for your patience. Packaging says it's probably not oxidation and most likely the clamping marks from when they coat the leads with tin and appears to be within the applicable standard. It should not affect the device in any way.

Thanks,

Gregory Thompson

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LM7800: LM7800