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Ground plane size and spacing in pcb design

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varunme

varunme

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Is this ground plane essential for this pcb, how much spacing is needed for the trace from the ground plane ?
this is a pic board , the ground plane and traces are too close , creating problem for making the pcb

**broken link removed**
 

The strange point that there is no ground plane at all. Neither VSS or any other net is connected to the copper pour.

Minimal copper to copper spacing depends on the available PCB technology. 0.15 mm can be achieved with commercially manufactured boards in standard technology, for DIY boards it depends...
 

A ground plane is a contigous or as near to a contigous plane with no traces breaking it up on a layer underneath the signal layers.
What you have is a copper pour (ground or other signal areas of copper, broken by traces on that layer).
The reason for using a ground plane underneath the traces is to provide a low impedance path for the return current. In your caswe if all the traces are on the top side then a double sided board with the bottom layer all ground would give you a true ground plane.
 
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    varunme

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    FvM

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As said grounding provides low impedance path .. I have heard they are essential for RF circuits ( Antennas, Amplifiers etc) !!!
Never heard that it is essential for PIC controller circuit!!!
 

If your PIC circuit is required to pass EMI tests respectively work reliably in a harsh industrial enviroment, you'll need at least a meshed low impedance ground. A continuous ground plane is surely beneficial.
 
"The reason for using a ground plane underneath the traces is to provide a low impedance path for the return current." what if high impedance path is thr for return current. is it necessary tht return current shld hav low impedance path. if yes why ?
 

Basics of electronics my friend.

if your return path is high impedant, say a 1 ohm, and the return current is 1A, then your ground level (at the GND pin of your IC) is not 0V, but 1V. I don't need to explain further I assume?
 
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    FvM

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I dont see a groundplane, I see plenty of floating copper that may be susceptible to EMI and pass it onto other tracks.;)
 
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So i need to get rid of this floating copper, isnt it ?
 

me advise use 0.5mm to 1mm spacing . and yes it is important to use ground plane to reduce noise issues , but your board might work perfectly without it .

another imporatnt use of using planes is that it helps in making finer details since the Acid has to remove less copper , so very thin wires are not indanger ....

hope that helps
 

Reed post #3 again regarding what a ground plane is...
Return currents and how they flow:
**broken link removed**
Also look up TEM wave propagation...
 

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