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21st April 2017, 12:10 #1
- Join Date
- Sep 2008
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LED footprint tolerances are way too slack?
The following “WICOP2 Z8 Y19” LED, on page 21, shows its footprint.
It says on page 21 that “Undefined tolerances are +/-0.2mm”
So do they mean that the gap between the pads is 0.3mm +/-0.2mm?, and that the pad dimension is 0.56mm +/-0.2mm?
How can we lay out a decent footprint with that kind of slack information?
Also, what does "Cu open" mean?
WICOP2 Z8 Y19” LED datasheet
21st April 2017, 12:10
25th April 2017, 11:09 #2
- Join Date
- Feb 2010
- UNITED KINGDOM
- 573 / 573
Re: LED footprint tolerances are way too slack?
Apply common sense to the data sheet... 0.2mm seems to be a generic tolerance that has been stated, probably not too relevant for a component this small. I would contact the firm (if you are so concerned) and ask for a proper mechanical drawing to your favourite standard. Me I'll just work on what data is given and apply a bit of common sense.
As I have said on another thread, generally LED PCB's are mostly copper with thin spaces between the copper, to prevent shorts. The phrase is probably referring to openings in the PCB copper, looking at the device and footprint to limit any movement during re-flow of the actual component.Also, what does "Cu open" mean?