[SI-LIST] Re: Skin depth,copper,gold

  • From: "Loyer, Jeff" <jeff.loyer@xxxxxxxxx>
  • To: Jonathan Riley <jonathan.lloyd.riley@xxxxxxxxx>
  • Date: Mon, 7 Oct 2013 00:06:03 +0000

It doesn't matter, unless you choose to plate the entire trace with ENIG.  That 
should never be done for a high speed design.
ENIG can be used for 10Gbps and upward as long as you don't make the mistake of 
plating the entire microstrip trace.  That's assuming you are using microstrip 
for your high speed traces.

Jeff Loyer

From: Jonathan Riley [mailto:jonathan.lloyd.riley@xxxxxxxxx]
Sent: Sunday, October 06, 2013 12:15 PM
To: Loyer, Jeff
Cc: balaseven@xxxxxxxxx; si-list@xxxxxxxxxxxxx
Subject: Re: [SI-LIST] Re: Skin depth,copper,gold

Hi all
Could someone clarify a two things regarding platings:
1. Concerning ENIG. The amount of gold used is tiny (certainly compared to the 
amount of nickel) and I thought that the effects of diffusion caused by the 
soldering process results in the effective layer becoming thinner still. For 
the sake of being able to make rough approximations, on an ENIG board it seems 
to make sense to just ignore the gold from an SI point of view. Please can 
someone advise whether this is really a fair thing to do and if possible say at 
what point the effects of the gold will begin to matter?
2. For boards running at 10Gbps upwards, what plating options are the best ones 
to choose? And which are best avoided?
Regards
Jonathan

On Sun, Oct 6, 2013 at 7:26 PM, Loyer, Jeff 
<jeff.loyer@xxxxxxxxx<mailto:jeff.loyer@xxxxxxxxx>> wrote:
On most designs, the ENIG is only applied to pads, etc. exposed by the 
soldermask, so it doesn't matter.  Plating the entire trace with ENIG is 
generally done only by mistake and causes a huge increase in insertion loss.

Jeff Loyer

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx<mailto:si-list-bounce@xxxxxxxxxxxxx> 
[mailto:si-list-bounce@xxxxxxxxxxxxx<mailto:si-list-bounce@xxxxxxxxxxxxx>] On 
Behalf Of bala
Sent: Saturday, October 05, 2013 2:47 AM
To: si-list@xxxxxxxxxxxxx<mailto:si-list@xxxxxxxxxxxxx>
Subject: [SI-LIST] Skin depth,copper,gold

Hi all,
When I model my surface microstrip trace,generally,I am taking properties of 
copper into consideration.and if my copper plated with gold or nickel,I am 
suspecting if we really need to consider the properties of plating material as 
well.One of the document says ,based on your skin depth choose your material 
property.My question is at low freq my signal uses my entire cross 
section(copper+gold) and at high frequency my skin depth shrinks and my signal 
uses outer surface of my conductor(gold on top side ,copper on bottom side).In 
both cases I should take both properties.How skin depth plays a role in 
choosing the material property (copper or both)while modeling microstrip?
Regards
bala

------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx<mailto: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<mailto:si-list-request@xxxxxxxxxxxxx> with 'help' 
in the Subject field


List forum  is accessible at:
               http://tech.groups.yahoo.com/group/si-list

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 forum  is accessible at:
               http://tech.groups.yahoo.com/group/si-list

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:

  1. Home
  2. si-list
  3. Archive
  4. 10-2013