Lpc2000

Hi!

Well, this is off topic from LPC's but here we go...

As my boards get more and more crowded I want to look at 4 layer PCBs
instead of my usual 2 layer ones. What I can't find is some good info
and tutorials of best practice and what you shall think of designing
a 4 layer card.

I guess (and hope) that some here in the group does 4 layer cards and
can point me somewhere or give a tip or two :-)

Looking forward to any input on the subject!

Cheers
/Johan

A quick rule of thumb for a 4 layer PCB, is to use the inner layers for 
power and ground planes.  Don't route any signals on the inner layers, 
keeping the planes as connected as possible.  If you have multiple power 
buses, you may be able to split the power plane, but be careful about 
routing signals on the adjacent layer that cross the gap between the 
planes.  This goes the same for the ground plane; avoid routing signals 
across a gap in the plane.  These last two rules are more important at 
frequencies higher than you're likely to encounter on an LPC, but it's 
good to get into the habit, and certainly doesn't hurt (and you'll have 
fewer bad habits to unlearn when you start playing with gigabit Ethernet ;-)

Hope that helps...

--DLM

fredrikssonjohan wrote:

> Hi!
>
> Well, this is off topic from LPC's but here we go...
>
> As my boards get more and more crowded I want to look at 4 layer PCBs
> instead of my usual 2 layer ones. What I can't find is some good info
> and tutorials of best practice and what you shall think of designing
> a 4 layer card.
>
> I guess (and hope) that some here in the group does 4 layer cards and
> can point me somewhere or give a tip or two :-)
>
> Looking forward to any input on the subject!
>
> Cheers
> /Johan

Hi.
Try to find book 'Analog-Digital Conversion' from
AnalogDevices, in this are all essential subject of
what you need and more and more. 
Section 9.2: PC Board design issues.
I think, it find at AD website, but I did not try to
find it, I have book from AD seminar.
Full index: 'Analog-Digital conversion, Walt Kester,
March 2004,'
Boris.
--- fredrikssonjohan <johan@...> wrote:

> Hi!
> 
> Well, this is off topic from LPC's but here we go...
> 
> As my boards get more and more crowded I want to
> look at 4 layer PCBs
> instead of my usual 2 layer ones. What I can't find
> is some good info
> and tutorials of best practice and what you shall
> think of designing
> a 4 layer card.
> 
> I guess (and hope) that some here in the group does
> 4 layer cards and
> can point me somewhere or give a tip or two :-)
> 
> Looking forward to any input on the subject!
> 
> Cheers
> /Johan
> 
> 
> 


Regards / S pozdravom Boris Kralik

http://www.geocities.com/kralikbo/
-------------------------------------------------


		
___________________________________________________________ 
To help you stay safe and secure online, we've developed the all new Yahoo! Security Centre. http://uk.security.yahoo.com

Johan, your PCB layout system should almost force you in the right
direction. We use PADS (we are just starting up a four layer board design),
and the first thing you do is to define the two inner layers. The most
common approach is to use one inner plane for ground and one for power, most
likely 3.3V. You identify the net names (GND and VCC) for the planes to the
CAD system, and then it will take care of making the plane connections for
you. You can also route on the inner layers if you want to, but it is
usually a good idea to have at least one plane reserved for ground.
http://www.mentor.com/products/pcb/pads/index.cfm is a good starting point.
Regards,
Lars

-----Original Message-----
From: fredrikssonjohan [mailto:johan@...] 
Sent: Monday, October 03, 2005 5:07 AM
To: lpc2000@yahoogroups.com
Subject: [lpc2000] OT: 4 layer PCB

Hi!

Well, this is off topic from LPC's but here we go...

As my boards get more and more crowded I want to look at 4 layer PCBs
instead of my usual 2 layer ones. What I can't find is some good info
and tutorials of best practice and what you shall think of designing
a 4 layer card.

I guess (and hope) that some here in the group does 4 layer cards and
can point me somewhere or give a tip or two :-)

Looking forward to any input on the subject!

Cheers
/Johan





 
Yahoo! Groups Links



 


-- 
No virus found in this incoming message.
Checked by AVG Anti-Virus.
Version: 7.0.344 / Virus Database: 267.11.9/118 - Release Date: 10/3/2005
 

-- 
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.344 / Virus Database: 267.11.9/118 - Release Date: 10/3/2005

On Monday 03 October 2005 06:07 am, fredrikssonjohan wrote:

> As my boards get more and more crowded I want to look at 4 layer PCBs
> instead of my usual 2 layer ones. What I can't find is some good info
> and tutorials of best practice and what you shall think of designing
> a 4 layer card.

"A Practical Guide to High-Speed Printed-Circuit-Board Layout

http://www.analog.com/library/analogDialogue/archives/39-09/layout.html

Despite its critical nature in high-speed circuitry, PCB layout is often one 
of the last steps in the design process, with sloppy layouts sometimes 
causing circuit designs that look good “on paper” to render mediocre 
performance. This article addresses high-speed layout from a practical 
perspective, discussing topics that can improve circuit performance, reduce 
design time, and minimize time-consuming revisions. "

-- 
     http://www.softwaresafety.net/ http://www.designer-iii.com/