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SMD ceramic capacitors

Views: 3106

#80722

SMD ceramic capacitors dark spots | 20 July, 2018

We have some MLCC capacitors that show some discoloration, or spots. Does anyone know if this will affect reliability? Caps test good - and assemblies function perfectly.

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#80736

SMD ceramic capacitors dark spots | 23 July, 2018

have not seen this issue personally, often identify cracks on MLCC parts but never dark spots.

May be worthwhile to replace as a precaution if at all possible.

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dwl

#80737

SMD ceramic capacitors dark spots | 23 July, 2018

I've never seen this before and I would be suspicious.

Have you tried to dust it off with a brush or Q-tip, it might just be some sort of process contamination.

Have you looked at the reel to see if the parts are coming in with these spots from the manufacturer? If the reels are clean, the next step would be to check your process and see if you can zero in on where they are appearing. Reflow, Wave solder, etc.Does this occur randomly, or in the same spot on the PCB? Have these PCBAs had power applied to them?

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#80738

SMD ceramic capacitors dark spots | 23 July, 2018

Thanks for your reply - parts in tape have similar markings - gets worse after reflow. ~20% have this issue. Units pass test no problem. Occurrence is random.

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