Hi
In my design, I am using the LTC3586 integrated circuit. I have a question regarding how to connect the exposed pad of the LTC3586 to the continuous ground plane. I have placed vias, but I am unsure how to connect them. Should I create the ground plane on the layer below? Thank you in advance.
As the text above your screenshot also states. it is more common to use the Other layer for the GND plane. The GND plane should be without any interruptions, and all the pads (especially for big IC’s) would cut big slots in the GND plane. Therefore, for a two layer PCB, put the footprints and the tracks on the top layer, and use the bottom layer for GND.
My circuit is quite complex, so I had to route some tracks on the bottom layer. However, there are fewer tracks on the bottom layer. I did this, but I still don’t understand how to connect the two (the continuous ground plane and the exposed pad of my integrated circuit).All passive components are connected between the LTC3568 and a GND. The GND pad is not connected to the continuous ground plane.
Again: Your GND zone is on F.Cu (red), while the usual way is to put it on B.Cu (Blue). When you put the GND zone on the bottom layer, then it will flow all around and under the IC, and you can put some via’s to connect the GND pad of the IC to the the GND zone. on the bottom.
Your screenshot only shows a very small section, but it does not look very dense.
Then I had a closer look at your screenshot:
Your footprint is on F.Cu (red) and I see 5 blue tracks that appear to go under a pad, but do not come out of it again. This is a very strong suggestion that you have some very fundamental misconception about PCB design. The Blue tracks are not connected to the red pads at all. If you look closely, you can also see small white lines near the center of those pads. Those are ratsnest lines and they indicate that connections are not yet made.
You may get a better understanding of the different layers in a PCB if you look at it in the 3D viewer (with **[Alt + 3]*) and then disable the board body and the solder mask layers. This makes your PCB transparent so you can look inside it.
Another subject you must look into is what vias are and how they work.
My was simple so I was able to dedicate the entire bottom layer to GND:
I was able to do that thanks to not having thermal pad under the main IC.
Recently I decided to use 4 layers PCB if I have IC with thermal pad that not allows me to go with VCC under it and spread radially from there.
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