Bill,
I would agree with John that if you don't specify a stack up
different houses could deliver you different stacks.
And in a pinch for meeting a delivery date etc even the same
house, I would expect, could vary.
But back when we were doing more 4 layers boards (like Charles said)
a number of the vendors when given no direction for a stack
were right around that just under .030 dielectric in the center
and built out symmetrically from there to be .062
So I guess the poor man's version of controlling stack up without specifying it though
is to set up a blanket spec with your house that all 4-layer cards will be whatever their
most standard is so at least all your boards from same vendor will be the same,
unless otherwise specified.
Bob
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Brooks, Bill
Sent: Wednesday, November 04, 2009 1:20 PM
To: [log in to unmask]
Subject: [DC] Standard construction for a 4 layer board...
I need to ask the designers and particularly the manufacturers a
question.
IS there a standard construction for a 4 layer FR4 board?
What thickness core and what prepreg arrangement would be used if I
asked for a IPC 4101/26 material to be used without specifying the
stackup thicknesses?
Best regards,
Bill Brooks | Datron World Communications, Inc.
PCB Designer/Engineer | Office: 760-602-7004| Fax: 760-597-3777 |
[log in to unmask]
1808 Aston Avenue, Suite 230, Carlsbad, CA 92008 | www.dtwc.com
Performance You Require. Value You ExpectTM
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