From: Jack Olson ([email protected])
Date: Fri Nov 12 1999 - 11:39:01 PST
I'm almost sure he meant the breakdown THROUGH the material (in the Z-axis)
It is much different ACROSS the surface of a board!
Jack
-----Original Message-----
From: Michel Bazinet [mailto:[email protected]]
Sent: Friday, November 12, 1999 9:26 AM
To: [email protected]
Subject: [SI-LIST] : Traces isolation vs FCC68
To whom it may concern,
I would like to know what you think about one of the
assertions of Mr
Lee Ritchey who said that the dielectric breakdown voltage
for a
standard
FR-4 Epoxy Glass is about 1100Volts/mils. On one of our
projects, to
pass the FCC68 test, we needed 1500 Volts of isolation on
some traces.
At
this
time when I made the PCB I checked in the IPC-D-275 table
(table 3-1,
P11,
september 91 edition) to find some very huge results (1500V
->
150mils). In
reality yon cannot design a project and keep this clearance
between 130
different nets. So in this specific project I kept an
isolation of
30mils
between each of the concerned traces. And in the Z axis I
increased the
thickness of the PCB to 115mils (just to be able to solder
every part
on
the pcb) on an 8 layer board. The problem with the tickness
of this
board
is that we have a lot of trouble with the fabrication and
the assembly.
Furthermore, it is more expensive.
When I spoke with Mr. Ritchey at the PCB Design
Conference he assured
me
that the table he gave me is correct. I would like to know
your opinion
on
this
topic, because I don't have any sources other than IPC. If
it's
correct, we
can
go down to a 0.062" pcb thickness and reduce the size of the
pcb.
We are currently working on a new version of this
board so I hope you
will
have some good news for us.
Michel.
__________________________________________________
Michel Bazinet [email protected]
PCB Designer http://www.nhc.com
NHC Communications Inc. (514) 735-2741 ext.: 262
5450 Cote de Liesse 1-800-361-1965
Mont-Royal, Quebec, H4P 1A5 Fax: (514) 735-8057
**** To unsubscribe from si-list: send e-mail to
[email protected]. In the BODY of message put: UNSUBSCRIBE
si-list, for more help, put HELP. si-list archives are accessible at
http://www.qsl.net/wb6tpu/si-list ****
**** To unsubscribe from si-list: send e-mail to [email protected]. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****
This archive was generated by hypermail 2b29 : Tue Feb 29 2000 - 11:39:46 PST