AnBer:

I realize that it is in writing on the Internet, therefore it must be true.

But, the board as documented by "SweedJesus" is a non-standard
and unusual construction for PC boards, therefore there is a slight
chance that the information is wrong.

I would suggest that you use the dimensions suggested by myself
and John.

Please also realize that the dimensions and parameters in building
PC boards that affect your E&M modeling are typically +/- 10 percent,
sometimes +/- 20 percent, so do not spend a lot of time chasing
decimal places for the input to your modeling program.


--- Graham

==



On Mon, Nov 24, 2014 at 6:12 AM, AnBer <[email protected]> wrote:

> Graham, John,
>
> Thanks for the comments.
>
> I finally found the layer stackup document for the BBB (revB4).
> Strangely enough I could not find it in a readable format from:
> http://elinux.org/Beagleboard:BeagleBoneBlack#Hardware_Files
> I found it at the below page for an older BBB version:
>
> https://github.com/SweedJesus/Beaglebone-Black-Stuff/tree/master/Docs/Beaglebone%20Black/BBB_PCB/BeagleBone_Black_RevB4_MFG
>
> From the beaglebone_black_RevB4_NOLOGO_FAB.pdf enclosed file looking at
> the different info I can see:
>    - TOP and BOTTOM layers are:    1/2 oz + 150 microinches of plating (ie
> 0.150 mils)
>    - INNER layers are:                      1 oz
> which seems different from what is defined from the BBB Altium PCB stackup
> (beaglebone_black_RevB4.pcbDoc):
>    - TOP and BOTTOM layers are:     2.4 mils
>    - Inner layers are:                         1.2 mils
> Using the below convert 1/2 oz should be 0.88 mils and 1 oz 1.37 mils:
> http://www.referencedesigner.com/cal/cal_02.php
>
> Am I missing something in the oz to mils conversion?
> Even if the Layer stack-up table from the .pdf file says that all
> dimension are in INCHES it looks like that the that it is oz and mils
> instead.
>
> In both document the total board height is 62 mils.
>
> AnBer
>
> On Wednesday, February 8, 2012 9:00:30 AM UTC+1, manatarms wrote:
>>
>> Dear All
>>
>> Does someone have the stackup of the BeagleBone PCB? I couldn't find
>> it on the hardware design page and it would help many people who want
>> to do their own design.
>>
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