TR-9 PCB, 4-layer

Hello everyone,

this thread shall serve as a way to organize design decisions and improvements for the upcoming 4-layer version of the TR-9 PCB.

I suggest FR-4 substrate with overall thickness of 1.2 mm. We should design components for automated assembly.
Maybe already for a specific manufacturer(JLCPCB?).

The stack-up would be as follows:
-. 35 um Top
→ 300 um Dielectric
-. 35 um GND
→ 550 um Dielectric
-. 35 um VCC
→ 300 um Dielectric
-. 35 um Bottom

So nothing too wild. Let me know what you think.
We also could take copper off Top/bottom and/or add width to the core for a more common(cheaper?) 1.6 mm overall thickness.

  • pthrr

As was suggested, maybe we can use the additional space and add a bluetooth module, e.g. BLUENRG-132 as available from JLCPCB

  • pthrr

Sounds good. Bump.

Wouldn’t it be better to try to keep to a standard stack? For example, JLCPCB’s stacks use 17um for the inner layers. Using 35um for both inner and outer would be a custom stackup which I’m guessing would increase the price quite a bit. This isn’t perhaps so much of an issue for larger orders, but at this point, isn’t it more likely people are going to be ordering a few boards to try?

I think so too. But we should first settle on a stackup(s) that serve our needs and then try to find a manufacturer that can handle this while keeping in mind our component choices.
I assume most PCBs will be manufactured in small batches anyway.

  • pthrr