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What does a fab note mean?

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cameo_2007

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what is meant by fab note?
the manufacturer asks me he needs the fab note too,along with the gerbers.
 

yalanand

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Re: what is a fab note?

Yeah i too faced the same issue...wat is it..?
 

cameo_2007

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what is a fab note?

they say,its a note in which the fabricaition details of the pcb will be given.like the thickness etc..

i donno much abt that...
anyone has any clear picture of that,pls lets knw.
who will make that? and is it really needed for high spped deign boards.?
 

popoyboys

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Re: what is a fab note?

i think it also contains the layer stackup, drill table and notes about some holes with special instructions..

Added after 11 minutes:

it also contains the layer stackup, drill table and notes about some holes with special instructions..
 

Rame

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Re: what is a fab note?

Hi,

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..

https://www.datacircuits.com/docs/Fabrication Notes Sample.pdf

herewith find a fabrication drawing with the notes in it...

https://www.datacircuits.com/docs/Fab Drawing Sample.pdf

Hope it helped you to some extent....

Regards

Ramesh
 

    cameo_2007

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cameo_2007

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what is a fab note?

yeah..that helped a lot to understand the stuff.

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??

regards,
 

majnoon

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Re: what is a fab note?

Hi cameo_2007,
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.

Good Luck,

M
 

cameo_2007

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what is a fab note?

thank you
i got the logic,i understood that part.

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..

regards,
 

raj_pcbtech

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Re: what is a fab note?

Please follow the link to get wall chart for PCB fabrication details.



Raj
 

chinta

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what is a fab note?

for fabricators, one needs to provide the material, finishings etc.. and the spec which you would like to follow.

Also if it is impedance controlled board, you have to specify the trace width and expected impedance and tolerances. This is a MUST for the impedance boards.
 

electron_boy

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Re: what is a fab note?

Fabnote:
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.
 

hyoree

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Re: what is a fab note?

cameo_2007 said:
what is meant by fab note?
the manufacturer asks me he needs the fab note too,along with the gerbers.

For the PCB manufacturer,it's mainly about fabrication holes.and including unless otherwise specified,such as the symbol/finish/legend ink/material/...the detail of the PCB.

Please have a general view for the attached file.
 

    cameo_2007

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