Electronics > Beginners
Is it possible to route this in 4 layer 5cm x 5cm?
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soFPG:
I never did a board with more than 4 layers and this is my first attempt and in general I am not very experienced in routing PCBs.

At JLCPCB a 4 layer 50mm x 50mm PCB is very cheap but as soon as the area goes above 50mm x 50mm it doubles in price - so it would be nice to get everything into this 5cm square.
But - maybe there is no way fitting every component? What do the PCB routing experts here say - is it possible (given JLCPCB capabilities of 3.5mil traces/clearance, 0.2mm via holes)?

It looks close to impossible to me especially that a lot of connections from the big BGA to the TSSOP and the other BGA should be matched regarding length.

My approach would be routing it like this and if it doesn't work out somehow re-arrange the components and then try again.
Yansi:
Why do you take a double-BGA high speed digital board as you first 4layer trial?

What pitch are these BGAs? If not 1mm, forget about making the PCBs in china  for dirt cheap.  0.8mm pitch BGA can be made successfully with a 0.25 drilled vias at maximum (or  maybe, seen them with .3mm drilled vias, while making sacrafices and bending the design rules a bit). Cheap chinese prototype pcbs end with .3mm drills.
soFPG:
Those are 0.8mm BGAs.

And JLCPCB lists 0.2mm as min via hole size: https://jlcpcb.com/capabilities/Capabilities

Edit: This is not very high speed. The TSSOP package is SRAM (12ns access time - so 80MHz) and the other BGA is NOR-Flash.
Howardlong:
Look at

o using 0402 passives (or smaller) unless there’s a reason to use larger;
o double sided load;
o starting with something a lot less ambitious, or get someone a lot more experienced to do it for you.

ebclr:
You can get some extra spaces, putting some components on the other side of the board, using the 2 faces, have more room to save space


By the way, is an FPGA, Memory, USB convert for jtag , or something like this?
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