I've been learning PCB designing lately to design a small controller board.The board has a micro-controller and its supporting components laid out as shown :

controller board.

After having gone through some nice threads here, about oscillator placement and here, about the importance of decoupling capacitors,their placement in the board and other critical considerations,I've come up with my own design which is a four-layer board.Can someone validate the same and suggest improvements (if,any) to the design? Thanks in advance.


1 Answer 1


If you have a four layer board, you presumably have a VCC and GND plane, which means that you would be better with a VCC via and GND via at each power-pin-pair/ decoupling cap. (The capacitor placement looks OK though)

Then get rid of almost all that VCC/GND tracking.

Don't worry about minimising via-count, if that was what motivated your design above.

  • \$\begingroup\$ My initial design was using through-hole components after which I stumbled upon Olin's excellent answer in the thread mentioned in my description. Apparently,you might circulate RF currents through the ground plane if you connect each of the supply and gnd pins through separate vias. OTOH,if you create a local net of Vcc and ground pins(separately,of course) and route them to their respective planes through a single via,chances are that you will not make the dedicated intermediate layers act like a patch antenna. So,having a hell lot of vias is never a problem for me. \$\endgroup\$
    – Adithya
    Nov 21, 2014 at 10:52
  • 2
    \$\begingroup\$ I really don't think you should worry about your power-planes radiating from under an AVR - you've got to think about getting the best layout overall, which is inevitably some kind of compromise. To me, the VCC track right around the chip looks horrible - it's a poor power-supply for a start, and it compromises the routing of pretty much every other track which leaves the chip. There's no point having power planes if you don't use them. \$\endgroup\$
    – user1844
    Nov 21, 2014 at 11:14
  • \$\begingroup\$ Routing the other components was excruciating to say the least. I have a design satisfying whatever you said. Went for the overkill! Thank you :) \$\endgroup\$
    – Adithya
    Nov 21, 2014 at 12:43

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