Sean,

I would also like to point out that there is some derating for frequency, 
although I don't have a reference for what the factor is.
High voltage is not very well behaved at high frequencies, and you'll need 
to avoid sharp corners at all costs.
I have personally seen less than 50kV @ ~1Mhz puncture 1/4" plate glass in 
under 30 minutes at a ragged conductor edge.

Frank



At 02:48 PM 3/18/2002 -0800, you wrote:
>Sean,
>         the standard answer from IPC for general purpose (Epoxy E-glass) FR4
>(is there such a thing today?)is 39,400 Volts/mm (approx. 62,500V at
>0.062"). This is derived from a test using 0.125mm and they warn that it
>should not be considered linear for high voltage applications with minimal
>dielectric spacing, i.e. less then 0.09mm (0.0035"). Don't think that counts
>for most general designs, that would be 3.5mil laminate.
>
>         Now a word of warning. This would be through the dielectric, not
>around the edge of the material, through air, nor over the surface(s).
>Considering most applications and the means for contamination of these
>surfaces, I would be checking the surface or around the edge requirements as
>well. Especially is there is copper near the board edges.
>
>Sincerely,
>Brad Velander.
>
>Lead PCB Designer
>Norsat International Inc.
>Microwave Products
>Tel   (604) 292-9089 (direct line)
>Fax  (604) 292-9010
>email: [EMAIL PROTECTED]
>http://www.norsat.com
>
>See us at Booth S8155 at NAB 2002 in Las Vegas April 8 - 11.
>
>
>-----Original Message-----
>From: Sean James [mailto:[EMAIL PROTECTED]]
>Sent: Monday, March 18, 2002 2:15 PM
>To: Protel EDA Forum
>Subject: [PEDA] Voltage standoff of FR4
>
>
>What is the voltage standoff (front to back) for .062" FR4?
>
>Sean James
>PCB Designer
>Telecast Fiber Systems
>102 Grove Street
>Worcester, MA 01603
>TEL 508-754-4858 x33
>FAX 413-541-6170

Frank Gilley
Dell-Star Technologies
(918) 838-1973 Phone
(918) 838-8814 Fax
[EMAIL PROTECTED]
http://www.dellstar.com

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* To post a message: mailto:[EMAIL PROTECTED]
*
* To leave this list visit:
* http://www.techservinc.com/protelusers/leave.html
*
* Contact the list manager:
* mailto:[EMAIL PROTECTED]
*
* Forum Guidelines Rules:
* http://www.techservinc.com/protelusers/forumrules.html
*
* Browse or Search previous postings:
* http://www.mail-archive.com/proteledaforum@techservinc.com
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

Reply via email to