Post by thread:[EE]: about PCB traces

I think is is a ground plane. David Andre Abelian wrote: {Quote hidden}> Hi to all, > > Apologize if the tag isn't right. > Friend of mine sent me a picture of this attached board > that I couldn't recognize the purpose of traces being like that. > The board is hatched by very specific way > Any idea why traces are like that? Is it for RF? > > Andre > > ------------------------------------------------------------------------ > Name: board2.jpg > board2.jpg Type: JPEG Image (image/jpeg) > Encoding: base64 -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Yes, but why the funky split-and-rejoin and weird bends? spam_OUTnickTakeThisOuTveys.com | http://www.veys.com/nick {Quote hidden}> -----Original Message----- > From: pic microcontroller discussion list > [.....PICLISTKILLspam@spam@MITVMA.MIT.EDU] On Behalf Of David P. Harris > Sent: Monday, February 11, 2002 12:38 PM > To: PICLISTKILLspamMITVMA.MIT.EDU > Subject: Re: [EE]: about PCB traces > > > I think is is a ground plane. > David > > Andre Abelian wrote: > > > Hi to all, > > > > Apologize if the tag isn't right. > > Friend of mine sent me a picture of this attached board > > that I couldn't recognize the purpose of traces being like > that. The > > board is hatched by very specific way Any idea why traces are like > > that? Is it for RF? > > > > Andre > > > > > -------------------------------------------------------------- > ---------- > > Name: board2.jpg > > board2.jpg Type: JPEG Image (image/jpeg) > > Encoding: base64 > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

At 10:30 AM 2/11/02 -0800, Andre Abelian wrote: >Hi to all, > >Apologize if the tag isn't right. >Friend of mine sent me a picture of this attached board >that I couldn't recognize the purpose of traces being like that. >The board is hatched by very specific way >Any idea why traces are like that? Is it for RF? Interesting. Many parallel traces have lower inductance than the same width in a single trace. The bonding, and "z" bends are puzzling though. That looks to add inductance. There's a lot of vias, which I suspect mean that there's a lot of high frequency current flowing, and they want to bond upper and lower ground planes. I've seen traces snaked to add inductance, but I've never seen one like this before! -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

I have never seen this technique before. I first thought of thermal relief. Then I noticed the large copper areas just to the right. I use Microstripping techniques all the time and I have never read about this type of Striplining. It could be shielding or absorption concepts. My guess would be capacitive elements and series inductance in a run to reduce the coupling of EMI/RFI type interference. Gordon Varney http://www.iamnee.com {Quote hidden}> > Hi to all, > > Apologize if the tag isn't right. > Friend of mine sent me a picture of this attached board > that I couldn't recognize the purpose of traces being like that. > The board is hatched by very specific way > Any idea why traces are like that? Is it for RF? > > Andre > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

At 12:47 PM 2/11/02 -0600, Gordon Varney wrote: >I have never seen this technique before. I first thought of thermal >relief. Then I noticed the large copper areas just >to the right. I use Microstripping techniques all the time and I have >never read about this type of Striplining. It >could be shielding or absorption concepts. My guess would be capacitive >elements and series inductance in a run to >reduce the coupling of EMI/RFI type interference. I was thinking on this some more.. It looks like the Z-bends are the best way to get around other things, and keep the trace inductance minimized. Apparently, they couldn't route the whole herd around the corners, so they made more or less a summing junction, then took off from there, with the max number of traces that they could fit around the bends, then re-summed, and carried on with whatever number of tracks would fit in the new space. Looks to me that this trace is VERY sensitive to inductance, and I would seriously look at the design to see if this is really necessary! Usually, when you get pushed this hard, you're doing something wrong. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Could it be similar to laminations in a transformer core? To stop magnetic a field (perpendicular to board) from inducing circulating currents in the board. It might also be some kind of strip line filter. What is the board from? We might be able to tell from context? Cheers, Don At 12:40 PM 2/11/02 -0600, you wrote: >Yes, but why the funky split-and-rejoin and weird bends? > >.....nickKILLspam.....veys.com | http://www.veys.com/nick > >> {Original Message removed}

Maybe its just something to make a would be reverse engineer go "huh?" Is this some kind of a high frequency device? ----- Original Message ----- From: Nick Veys <EraseMEnickspam_OUTTakeThisOuTVEYS.COM> > Yes, but why the funky split-and-rejoin and weird bends? -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

> Any idea why traces are like that ? Did the person who drew the board have a lazy afternoon and just threw in some patterns ? Or did they just not have a clue what they were doing ? Ditto for whatever routing software was used Are the patterns part of the design for another board, which on this model are unused and shorted at various points ? How many of them are part of the supply lines / ground plane ? -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

-----Original Message----- From: Jinx [joecolquittspam_OUTCLEAR.NET.NZ] Sent: Monday, February 11, 2002 9:55 PM To: @spam@PICLISTKILLspamMITVMA.MIT.EDU Subject: Re: [EE]: about PCB traces >Did the person who drew the board have a lazy afternoon and just threw in some patterns ? that's more like it. But I can't stop admiring the pcb paterns for rf areals, they look pretty. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

I have an old PCB CAD tool that just won't do copper pours or fills around corners very well. Perhaps the odd designs are that person's way around a similar limitation. The board looks pretty neat and clean otherwise though. Doesn't that give the impression that the designer knew what he was doing? Can't wait to hear what the board is from.... Chris {Original Message removed}

Original message from: Andre Abelian <KILLspamengelecKILLspamEARTHLINK.NET> > >Hi to all, > >Apologize if the tag isn't right. >Friend of mine sent me a picture of this attached board >that I couldn't recognize the purpose of traces being like that. >The board is hatched by very specific way >Any idea why traces are like that? Is it for RF? > >Andre > Maybe to facillitate wave soldering? ie the solder flows along the traces? Ian __________________________________________________________________ Get your free Australian email account at http://www.start.com.au -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

I asked one of the guys I work with, he thought that it might be an attempt to achieve impeadance matching: there may be an inner layer with signals that line up with these traces, possibly with internal vias under the larger copper-grouping areas. Also note, the many separate copper traces would have lower capacitance with an internal layer than a solid/wide ground plane would... Taken a step further: He mentioned that he knows of one company that actually makes coax-equivelent shielded traces by having enclosing traces on the two adjacent layers and laser drilled plated micro-holes bonding the enclosing layers. Bruce. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

For some reason this email never reached me. I assume the file was an attachment, maybe our incoming virus grabber nabbed it without notifying me. It sounds like the Z traces could be an attempt at adding series inductance in power traces as a filter for noise. {Quote hidden}>From: Andre Abelian <RemoveMEengelecTakeThisOuTEARTHLINK.NET> >To: <spamBeGonePICLISTspamBeGoneMITVMA.MIT.EDU> >Sent: Monday, February 11, 2002 7:30 PM >Subject: [EE]: about PCB traces > > > Hi to all, > > Apologize if the tag isn't right. > Friend of mine sent me a picture of this attached board > that I couldn't recognize the purpose of traces being like that. > The board is hatched by very specific way > Any idea why traces are like that? Is it for RF? > > Andre > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.