multi-layer pcb stackup

[pgg]

First, let me say I was very happy to find this site. I am an old time user of PADS, but have been away for a short time.The info here is helping me get back up to speed very quickly.
What I am looking for is info or a site that will have what is usually available on layer pairs for standard layering dimensions on multi-layer boards.Thanks.

[Tom]

Go to the Site Index / General Documentation / Standards / Layer Configurations > Here is the shortcut....

http://www.pcbstandards.com/downloads/Metric%20Environment/General%20Documentation/Standards/Layer%20Configurations/

[Jon Kelly]

Hi,

I am looking for some information, I am just getting to grips with PCB construction Cu thickness Vs Prepreg thickness etc and was given the following information from the board manufacturer on usual 6 layer stack up:
FOIL 0.5OZ COPPER
2 X 2116 PRE-PREGS
0.018” CORE 1OZ COPPER
2 X 2116 PRE-PREGS
0.018” CORE 1OZ COPPER
2 2116 PRE-PREGS
FOIL 0.5OZ COPPER
I am trying to plug in the values into PCB-Toolset-V2.1 for impeadance stackup calculator & Microstrip calculator as I have a Differential Pair on the Top Layer. My problem is I am having difficulty in translating the above information into the relative thicknesses for the calculator. Could someone please help in translating the above into values I can plug into the calculators?
My Layer stack in Power PCB is as follows
Top - Signal
Layer2 - Signal
Layer3 - Power
Layer4 - GND
Layer5 - Signal
Bottom - Signal
Can this stack be used in the Stackup Impeadance Calculator? In the Ref Upper & Ref Lower it doesn't seem to accept that Layers 3&4 are Planes and that Layer 5 should ref Upper to Layer 4 etc.

I know that there are a lot of questions here but any help would be much appreciated.

Thanks
Jon

[Tom]

Jon,

This six layer stack-up has problems:
Top - Signal
Layer2 - Signal
Layer3 - Power
Layer4 - GND
Layer5 - Signal
Bottom - Signal

You cannot control the impedance on the outer layers. Not to mention that the outer layer signals do not have a return path reference plane. I guess it's OK to use this type of construction on a Power Supply board or a very slow speed board.

What you really want to use is this 6 layer configuration:
Top - Signal
Layer2 - Power
Layer3 - Signal
Layer4 - Signal
Layer5 - GND
Bottom - Signal

This way every signal layer has a return path reference plane.

Rule of thumb - Try to avoid having signal layers on the Layer 2 and the layer next to the Bottom. Always use planes unless you use the outer layers for fanout only and copper flood the rest.

One last thing, always communicate with the PCB manufacturer who is going to build the board. They will always provide assistance in the form of an Excel Spread Sheet that indicates the complete board construction.

[Jon Kelly]

Thanks for the great info provided. I have only been laying out PCB's seriously for the last 6 months as it is now part of my duties as Electronic Engineer, so I am just starting to get to grips with larger more complex designs with stiffer requirements than Single sided PTH PCB's, So your advice is very much appreciated.

Thanks Again
Jon