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Fabrication notes contains the details of Pcb thickness,layer stack up,copper thickness i,e 1 ounce or 2 ounce,surface finish,Filling the vias,contolled impedance etc in the fabrication drawing..you can addup many more points according to your requirement.
Underneath, i have attached a link,go through it for reference..
n the next is,
i gave a single board computer gerbers for manufacturing.?But i havent given any fab note to them.
Now while testing the board,i suspect some impedance issues in the board which is making the board to malfunction.
Then when i spoke to the mfrs,they said,i am suppose to mention all those impedance constraints in the fab note,which i havent.
now,i am not really sure whether that is the problem or not,and i dont have any fab notes.
From where do i get that note..do i need to make it my own?
or will that be the real problem..the impedance??
It looks like you did not read sample Fab notes from previous reply properly.
First, every Board can have different spec. hence different instructions on fab notes.
In your case you should specify which traces have impedance and what is the value, which layers they are, what is refernce plane(s) and distance between layers. Test coupons can be requested to make sure that baord house have done
what you wanted them to do.
my q now is,
will this impedance stuff really matter for high speed design,as i am a beginner in this tech,donno how it is.
I already manufactured the board and is in the testing stage.Now i'm worried whether i shud re-make it by taking those impedance into consideration..
it is a document given to the fab shop along with the deliverables to them, gerbers.
if u have some impedance spec, say that in fab note. what all u want say the fab shop to take care, put those in to a neat doc file and that is fab note.
"Do i need to take care of impedance for digital boards":
yes u need to look at the impedace and change in impedance for high speed boards. whenever the signal sees an impedance change while traveling, some part of the signal gets reflected and these contribute to ringing. and u must have controlled impedance for particular type of signals say ethernet lines need 100ohm diff impedance.