JLCPCB can support up to 0.15 vias. I'm using 0.3 hole/0.5 pad since I'm using 2 layer PCBs.
https://jlcpcb.com/capabilities/pcb-capabilities
I'm not finding any "ideal dimension" for signal traces on the web...? They seem unanimous to say "however small your PCB fabricator can handle".
I'm using:
- 0.2 traces default,
- 0.3 for USART/USB,
- 0.3 for VDD.
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