I have a trace width calculator on my web site at
http://www.aracnet.com/~gpatrick in the "PCB Data" section. It is based on
equations from IPCWorks 97 (McHardy/Gandhi, Hughes Aircraft TP SO6-2-1).
There is already some slack in the calculations, but it depends on the
nature of the surge as much as how much surge current you are handling. If
you are worried about a surge that occurs infrequently, for very short
periods you might be able to go with the calculated value. What I normally
do is calculate width at the steady-state current at a 10 degree rise,
calculate trace width at the surge current at a 60 degree rise, then decide
how wide to make the trace based on the time the surge is expected to be
present.
I am planning on incorporating some "fusing current" calculations into the
calculator when I get a spare moment. These are based on a presentation
from Doug Brooks at PCB East 2000.
--
George Patrick
Tektronix, Inc.
Central Engineering, M/S 39-512
P.O. Box 500
Beaverton, OR 97077-0001
Phone: 503-627-5272 Fax: 503-627-5587
-----Original Message-----
From: Amira Mohammed [mailto:[log in to unmask]]
Sent: Monday, February 26, 2001 01:39
To: [log in to unmask]
Subject: Re: [DC] Trace width
Dear Phil and Gary,
Thank you for both of you
You are right .When I've asked about this,I told that we want some safty
factor for surge current , so should I calculate the trace width depending
on the maximum current value may be take place due to surge current, or
there is another way to calculate it?
Thanks in advance
Regards,
Amira Mohamed
PCB Designer
IEP
www.bahgat .com
> ----------
> From: Gary Ferrari[SMTP:[log in to unmask]]
> Reply To: DesignerCouncil E-Mail Forum.;[log in to unmask]
> Sent: Monday, February 26, 2001 4:21 AM
> To: [log in to unmask]
> Subject: Re: [DC] Trace width
>
> Amira,
>
> I tend to agree with Phil on this one. The 5 amp current should be a
> continuos value. Is there any possiblilty that you may be seeing a surge
> current of a much larger value when you turn on the circuit?
>
> Regards,
>
> Gary Ferrari
> Executive Director
> IPC Designers Council
> 860-350-9300
> Fax 413 771-5386
> [log in to unmask]
>
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