[SI-LIST] Re: permissable current density in PCB copper
- From: "Istvan Nagy" <buenos@xxxxxxxxxxx>
- To: "Roopesh Badala" <roopesh.badala@xxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Sat, 12 Nov 2011 23:07:10 -0000
Hi
I think what you are talking about is a multi-physics problem.
The websites on current density are talking about uniform current density
over a whole cross-section of a wire, while your chese-plane has non-uniform
current density. The higher current areas are attached (they are parts of
the same plane) to lower current areas which act as a heat sink, so the
small areas can carry more current than they could if all their neighbours
were carrying the same high current.
Basically I think it should be simulated with a simulator which does both
electrical and thermal simulation in the same time, and seek for peak
temperatures against PCB delamination limits. Maybe you could get somehow
the average value of that current for the whole power plane, and compare
that with the numbers given for wires. I'm not sure if your hyperlynx can do
that averaging, but for example the free FEMM program that I use can do all
kinds of integrals which may give you the average.
I encounter the same problem when doing DC power plane analysis, since I
dont have a solution for it (I dont have a multi-physics field solver), I
just ignore the higher current-density areas and focus on the voltage drop.
regards,
IStvan Nagy
-----Original Message-----
From: Roopesh Badala
Sent: Saturday, November 12, 2011 8:31 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] permissable current density in PCB copper
Dear Experts,
What is the maximum permissable current density in pcb copper.
I am working on PI analysis of a PCB design using Hyperlynx PI.
at certain regions on the power plane shape, i see current densities of
220A/sqmm. ( in the area below BGA pins where via anti pads are causing
swiss cheese effect )
I could not find any where a specification which says about the limits.
please advise.
Best Regards
Roopesh
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
