Let's say I have a multilayer board with a single dedicated ground plane.

Should I place all the grounds directly to the plane with a via as close as possible to the pin/pad or should I be looking at different layout methods like a star topology where all grounds traces converge to one point and then go to the ground plane ?

  • \$\begingroup\$ possible duplicate of Decoupling caps, PCB layout \$\endgroup\$ Oct 14 '13 at 13:06
  • \$\begingroup\$ That duplicate may sound like a different question, but my answer to it also answers your question. \$\endgroup\$ Oct 14 '13 at 13:07

It depends of your device. Ground routing is sometimes a black magic. ;)

And very often, on most complex circuits there are several grounds as well.

But if your device is simple and plain digital, then yes, connect directly to the ground plain. That is why it is there.

On the other hand, few devices really need multilayer boards. In most cases with careful design you can use two or even one layer board for the same schematic.

  • \$\begingroup\$ Ya apparently proper understanding of signal integrity seems to require some skill in sorcery. The board is primarily digital. Would the answer be much different if there were analog components as well ? Would a split ground plane connected at a single point be better for a mixed signal design ? \$\endgroup\$
    – efox29
    Oct 14 '13 at 10:31
  • \$\begingroup\$ @efox29 Yes, analog and digital parts of the schematic usually need separate grounds, connected in one point. \$\endgroup\$
    – johnfound
    Oct 14 '13 at 10:36
  • \$\begingroup\$ When people refer to one point, does that actually mean one point, like 1mm bridge or just an area of arbitary "small" area. Smaller the better ? What is this sorcery! \$\endgroup\$
    – efox29
    Oct 14 '13 at 10:39
  • \$\begingroup\$ @efox29 - "point" is a mathematical abstraction. In reality there is always some finite size area. :) \$\endgroup\$
    – johnfound
    Oct 14 '13 at 11:16

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