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This is the first time I am designing a 4 layer PCB. The circuit will work on multiple frequencies: Signal acquisition part works on few Hz to 200 Hz(max), but one portion of the circuit will generate 13.56MHz. Power supply is 3.3V from a Lipo battery. I am planning to stack the layers as follows:

  1. Signal

  2. Ground Plane

  3. Power Plane

  4. Signal

I am using KiCad. I have already created ground plane and power plane. I have connected the negative terminal of battery to the ground plane by via. The schematic has a lot of ICs which require ground. I am just connecting those pads to the ground plane by vias too.

My question is: Do I have to route the connections in ground plane layer(all of them together, I mean do I have to connect them together again in ground plane-2nd layer of my PCB) or will the vias from the IC pads (supposed to be connected to ground as schematics) to ground plane will do? My understanding is, ground plane is full of copper unless I route any signal through them.

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    \$\begingroup\$ It has been a while since I used KiCad, so I'm not sure if this is true for KiCad. In general, if your define a plane and attach the gnd net to it, you vias will connect to the plane and there is no need to route the gnd connections in the plane. \$\endgroup\$ – Peter Karlsen Jun 21 '17 at 8:07
  • \$\begingroup\$ «Do I have to route the Valerie Varda connections [...]?» I didn't know that idiom :D! \$\endgroup\$ – user59864 Jun 21 '17 at 11:39
  • \$\begingroup\$ If you have a properly poured ground plane, then you do not need to run tracks between the ground VIAs on any layer. They will connect through the plane and no additional connection work is necessary. \$\endgroup\$ – pgvoorhees Jun 21 '17 at 11:51
  • \$\begingroup\$ Sorry for the typos. I don't how did I end up with a weird phrase like this. I edited it. @Nasha \$\endgroup\$ – sbz Jun 21 '17 at 17:20
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In KiCad, to create a GND plane you have to use the "Add Filled Zones" button from the toolbar normally visible on the right side of the screen. Select the layer you want this zone to be at and draw your plane. You would usually want to cover the whole layer with this zone / GND plane.

After doing this, every normal GND via that you add it will automatically go through all layers and will automatically be connected to the GND plane as well. I mentioned normal via, since there are the blind and burried vias, which wouldn't necessary mean that they would be automatically connected to your GND vias.

In the end, you can anyway control if there is a connection or not. If your via is shown to have a thin white line attached to it, that seems to be connected to an IC GND pin or some other GND point on your board, then you know that the intended connection to the GND is not done.

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My understanding is, Ground plane is full of copper unless I route any signal through them.

If you have a ground plane, do not route tracks through it. That defeats the object of having a ground plane. It's OK for the ground plane to have holes where signal/power vias go through, but don't let the holes join up into a slot.

Vias to the unbroken ground plane will be OK. But be aware that a ground plane is not zero resistance. It's real copper, and has a small and finite resistance, and is extended so has a finite inductance, so currents flowing through it can generate voltages. Lay your sensitive components out so they they don't see the voltages generated by heavy or rapidly changing currents. This often sort of works out OK with a reasonable floor plan (analogue here, power there, logic over there), but it's still too easy to mess it up. If you let holes line up to make slots, or route signal tracks through your ground plane, this increases its inductance and resistance dramatically, and increases interference from high current to sensitive regions, so don't.

If you only have one power rail, and only logic ICs, then a power plane makes sense. In a mixed signal board, it tends not to work to your advantage, as even if you don't have several rails, you will probably want several different distribution regions, a 'quiet' rail for your analogue and 'noisy' rails for logic or oscillators, each individually filtered. Route your power with tracks, by all means mostly on layer 3, but don't get too stressed about putting power and signals on all three non-ground layers.

Did I mention not to run tracks through your ground plane?

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  • \$\begingroup\$ +1, no traces, slots, or other interruptions on GND plane. Also, usually you'll have tons of vias. Using a polygon or copper pour makes the CAD software work hard as it has to recalculate the pour every time you add a non-GND via. CAD software usually have a a special "plane" mode which makes this fast, not recalculating the whole pour. \$\endgroup\$ – peufeu Jun 21 '17 at 10:09

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