Don,
The only thing I would caution is how it is specified on the drawing...
If you say -
"Material: FR4"
and nothing else you might end up with a lower Tg material that just happens
to be on the shelf of the supplier on that day... there are many grades of
FR4...
But if you specify the IPC-4101 spec you will have specified the criteria
for the material exactly.
Standard FR4 material (IPC-4101/21) has a min. Tg of 110 deg C.
So I would advise to be specific and you should have no problems...
At a bare minimum I would at least specify the Tg that the material must not
be lower than... or something like that if you choose not to use the IPC
specs to define it.
Good luck.
Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
_______________________________________
Member of the San Diego Chapter of the IPC Designers Council
Communications Officer, Web Manager
http://dcchapters.ipc.org/SanDiego/
http://pcbwizards.com
-----Original Message-----
From: Don Larisey [mailto:[log in to unmask]]
Sent: Thursday, April 21, 2005 2:12 PM
To: (Designers Council Forum); Brooks,Bill
Subject: RE: [DC] High Temperature Environment
We have been specifying a minimum Tg of 170 deg C lately on all of our
boards, and most shops have been supplying Tg of 180 deg C as a standard
value.
I don't know how much I can say about our product to be able to give
more information. I was asked this morning if the board material we
specify was adequate for this environment.
It looks like we will be OK.
Thanks,
Don
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of
Brooks,Bill
Sent: Thursday, April 21, 2005 5:01 PM
To: [log in to unmask]
Subject: Re: [DC] High Temperature Environment
Dennis,
That seems to be a great choice based on the limited information
supplied...
If more margin is needed for unknowns you could try the FR406
IPC-4101/26
which has a minimum Tg of 170 deg C
http://www.isola-usa.com/images/uploaded/FR406Bulletin-1.pdf
FR408 IPC-4101/24 has a minimum Tg of 150 deg C although ISOLA brand
material claims 180 deg C. But I am basing that off the IPC-4101 spec.
http://www.isola-usa.com/images/uploaded/FR408Bulletin2.pdf
I would specify the IPC-4101 spec because that is not vendor specific.
Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
_______________________________________
Member of the San Diego Chapter of the IPC Designers Council
Communications Officer, Web Manager
http://dcchapters.ipc.org/SanDiego/
http://pcbwizards.com
-----Original Message-----
From: Denis Lefebvre [mailto:[log in to unmask]]
Sent: Thursday, April 21, 2005 1:19 PM
To: [log in to unmask]
Subject: Re: [DC] High Temperature Environment
I think I'd be inclined to go with FR408 or any IPC4101/24 grade
material.
-----Original Message-----
From: Don Larisey [mailto:[log in to unmask]]
Sent: Thursday, April 21, 2005 1:13 PM
To: [log in to unmask]
Subject: [DC] High Temperature Environment
We are looking at putting a small board with all components rated to
125C into a sustained working environment of 120C. Should we be
specifying a different board material other than FR4. This is a small
double sided board about 25mm X 40mm with components both sides.
Any comments???
Don
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