Transforming 4 layer board to 6 layer pcb

[Abdelrhman Atta]

Hello, in the design reference it explicitly mentions:

“Important note on C9: The grounding of the C9 capacitor MUST be isolated from ALL ground layers except the bottom ground layer.”

However, this reference is for a 4-layer PCB. I am designing a 6-layer PCB with the following stack-up:

• Layer 1 (Top): Signal + Components (RF, high-speed digital)

• Layer 2 (Inner 1): Solid Ground (GND)

• Layer 3 (Inner 2): Internal Signal Routing (Great for routing messy I2C/SPI lines without breaking ground planes)

• Layer 4 (Inner 3): Power (VCC)

• Layer 5 (Inner 4): Solid Ground (GND)

• Layer 6 (Bottom): Signal + Components
  
  

What should I do with this capacitor, and where should I connect it?

Also, is there anything I need to consider in the design reference when using a different stack-up?

[Kenneth]

Hello,

I recommend that you send us schematic and layout for us to review before you send any boards to prototype production. Make a private case.

C9 needs to be grounded to layer 5 in your case, and you can have cut-out in layer 2 like it's done for the mid layers in the 4-layer board.

Kenneth

[Abdelrhman Atta]

Hi, I will once i am done, but another question the polygon cutout around the matching filter extended from top layer to layer 3 on the 4layer design reference, should be polygon cutout from top layer to bottom layer except for layer 5 right on 6layer pcb?

[Kenneth]

Yes, cut-out on layer 2-4 in your case should do the job.

Kenneth