Homebrew PCBs

There can be problems with having large planes near high frequency
signals as you get more capacitive loading, but I usually work on power
converter stuff where huge copper pours are about the only effective way
to both get heat out and to absorb 100MHz range ringing from 40V/ns edges.

--Adam.

On 04/07/11 08:23, Andrew wrote:
> Adam,
> 
> This gets at an issue I was wondering about -- I was aware of designs that have a power plane on one side and ground plane on the other, and was not sure what the advantage would be, though I suspected it might involve some capacitance. I wondered whether that capacitance was always a positive phenomenon, or could ever be negative.
> 
> But for this particular board, the issue is moot -- there are three different voltages on the board, and the layout would prevent any of them from filling much of a zone. Thus I was thinking about a ground plane on top ... but wondered if there were any possible negative effects of doing so.
> 
> Thanks for the input -- it helps to relieve a little of my woeful ignorance!
> 
> --- In Homebrew_PCBs@yahoogroups.com, Adam Shea <shea0097@...> wrote:
>>
>> Really depends on what you're doing.  For my power converter stuff I do
>> a power plane on one side and ground plane on the other as it acts as a
>> nice capacitor to short out ~100MHz kind of stuff.
>>
>> --Adam.
>>
>> On 04/06/11 20:52, Terry wrote:
>>> Generally speaking, the more ground plane -- top and bottom -- the better.  The last step in most of my designs is to do a polygon fill tied to GND on both sides of the board.
>>>
>>> --- In Homebrew_PCBs@yahoogroups.com, "Andrew" <a_wake@> wrote:
>>>>
>>>> I am closing in on designing a board that is a mix of SMD and through hole parts. I am using a zone on the bottom side to provide a ground plane; I wondered about adding a zone to the top as well. If I did a top zone, is there any reason I can't make it a ground plane as well?
>>>>
>>>
>>>
>>>
>>>
>>> ------------------------------------
>>>
>>> Be sure to visit the group home and check for new Links, Files, and Photos:
>>> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>>>
>>>
>>>
>>
>>
>>
>>
>> [Non-text portions of this message have been removed]
>>
> 
> 
> 
> 
> ------------------------------------
> 
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> 
> 
> 




[Non-text portions of this message have been removed]