[SI-LIST] Re: Tip and Ring routing consideration

 




I don't agree with making the etch wider meets the isoloation prarameters.  
First you have to make an 600 volt isolation criteria dictated by FCC part
68- that mean keeping the etch between T and R away from each other in all
directions - Second, these etches should be absolutely kept away from any
ground or voltage planes after the transformer and/or including the opto
device (if applicable).    Etch width is totally irrelavant , there is no
impedance requirements per FCC rules.


Keith Kowal 

Electronic Product Design epd2001usa@xxxxxxxxxxx[1]   [2]  [3]   


>From: hariharan <hariharan@xxxxxxxxxxx>
>Reply-To: hariharan@xxxxxxxxxxx
>To: suganthi@xxxxxxxxxxxxx, si-list@xxxxxxxxxxxxx
>Subject: [SI-LIST] Re: Tip and Ring routing consideration
>Date: Wed, 29 Jun 2005 16:29:30 +0530
>
>Hi Suganthi,
>
>The traces have to be wide enough (40 mil) to meet the isolation
parameters.
>There is a good application note with Intel about Layout consideration for
>their E1/T1 transceivers, you can use that as reference.
>
>Regards
>hariharan
>
>-----Original Message-----
>From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
>Behalf Of Suganthi
>Sent: Wednesday, June 29, 2005 4:13 PM
>To: si-list@xxxxxxxxxxxxx
>Subject: [SI-LIST] Tip and Ring routing consideration
>
>Hello All,
>
>
>
>What consideration to be taken care for TIP and Ring (Telecom domain)
>pair routing in PCB layout , and let me know the reason also.pls send me
>if u have any guidelines regarding this.
>
>
>
>Advance thanks for your Help!!
>
>
>
>Regards
>
>Sug
>
>
>
>
>
>
>
>-------Original Message-------
>
>
>
>From: Sol.Tatlow@xxxxxxxxxxxxxxx
>
>Date: 06/29/05 15:12:13
>
>To: gzilber@xxxxxxxxxx; billw@xxxxxxxxxxx; si-list
>
>Subject: [SI-LIST] Re: Fixing a black pad
>
>
>
>Hi Gil,
>
>
>
>The 'Black Pad' phenomonen is well known in the industry - the root
>
>of the problem is generally the nickel plating applied during the
>
>ENIG (electroless nickel immersion gold) plating process, where a
>
>corroded nickel layer leads to weak solder joints after assembly.
>
>This phenomonen therefore only affects boards with ENIG plating,
>
>and although reflow temperature/profiles may exacerbate the problem,
>
>they are not the real cause.
>
>
>
>The worst part is, you cannot detect it optically before assembly -
>
>it only becomes apparent when the joints fail, as you found out.
>
>And, if you have this problem with one board, you will most likely
>
>have more boards coming back to you with the same problem, since it
>
>is related to the plating bath (which was no doubt used to produce
>
>a whole batch of your boards).
>
>
>
>AFTER failure, there is not too much you can do about it - with an
>
>aggressive flux you may succeed in soldering the component back
>
>onto the board, but since the problem is with the nickel plating
>
>(which, due to corrosion, allows the copper underneath to interact
>
>with the joint), reworks are likely to suffer a similar fate (even
>
>if the reworked component SEEMS to be properly soldered). PLUS,
>
>even if only one BGA on the board has failed, if there are others,
>
>they are also likely to fail at some point. The safest solution,
>
>if also the most expensive (short term!), is to replace the board.
>
>
>
>For the future, since finding a PCB manufacturer who can produce a
>
>reliable ENIG finish is easier said than done (not because they
>
>don't exist, rather, because you only know if they weren't reliable
>
>when they prove it!!), for the future you may want to consider
>
>immersion tin or silver. These have other disadvantages (there is no
>
>perfect surface finish), but they tend to give overall better results.
>
>The best thing to do is do some Googling/reading about the subject,
>
>and decide on the basis of your specific needs.
>
>____________________________________
>
>Sol Tatlow, M.Eng. (Oxon)
>
>ProDesign Electronic &CAD Layout GmbH
>
>Product Developer
>
>Albert-Mayer-Str. 16
>
>D-83052 Bruckmuehl
>
>Phone: +49 (0) 8062-808-302
>
>Fax: +49 (0) 8062-808-333
>
>Mailto:sol.tatlow@xxxxxxxxxxxxxxxxxxxx
>
>www.prodesign-europe.com
>
>____________________________________=20
>
>
>
>
>
>
>
>-----Urspr=FCngliche Nachricht-----
>
>Von: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] =
>
>Im Auftrag von Zilber Gil
>
>Gesendet: Dienstag, 28. Juni 2005 16:33
>
>An: billw@xxxxxxxxxxx; si-list
>
>Betreff: [SI-LIST] Re: Fixing a black pad
>
>
>
>
>
>Hello Bill,
>
>Thanks for the response. The pad finishing was ENIG and the BGA have
>
>SnPb solder balls. I saw the Black pad only after removing the BGA
>
>components that was mounted more then a year ago (due to
>
>disconnections). Is it possible that it is not a real black pad but too
>
>low reflow temp in this components (partially could soldering) causing
>
>to oxidation of the Ni?
>
>
>
>Thanks,
>
>Gil=20
>
>
>
>-----Original Message-----
>
>From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
>
>On Behalf Of Bill Wurst
>
>Sent: Tuesday, June 28, 2005 2:46 PM
>
>To: si-list
>
>Subject: [SI-LIST] Re: Fixing a black pad
>
>
>
>Gil,
>
>
>
>I'm wondering if the black pad is silver (Ag) oxide. Have you recently
>
>switched to lead (Pb) free processing? Or worse, has your BGA vendor
>
>begun to supply you with lead free parts without your knowledge?=20
>
>Unfortunately, I'm not very knowledgeable when it comes to silver solder
>
>processes, but would like to hear from anyone else with more knowledge
>
>than I in this area. We may all need to learn about this quickly as the
>
>electronics industry makes the lead-free transition.
>
>
>
>-Bill
>
>
>
>
>
>/************************************
>
>/ billw@xxxxxxxxxxx /
>
>/ /
>
>/ Advanced Electronic Concepts, LLC /
>
>/ www.aec-lab.com /
>
>************************************
>
>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=

>
>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=

>
>=3D=3D=3D=3D=3D=3D=3D
>
>Zilber Gil wrote:
>
>>Hello all,
>
>>After removing a BGA components a black pads was seen on some of the=20
>
>>pads. Is it possible to fix it? If trying to use activated flux it is=20
>
>>possible to coat the pad with solder (receive back the wetting). Does=20
>
>>the black pad phenomenon will appear again on this pad (will I=20
>
>>encounter it later on other pads?)?
>
>>=20
>
>>=20
>
>>=20
>
>>Thanks,
>
>>=20
>
>>Gil Zilber
>
>>=20
>
>>Elta systems
>
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