Stand-off and front-panel grounding scheme possibly not correct
The standoff and front-panel of each side are connected together and
optionally connected to Gnd via R//C.
The FMC spec reads:
- Rule 3.19: FMC front-panel shall be isolated.
- Rule 3.23: the standoffs shall be tied to ground.
With the SMC connectors that are screwed onto the panel, we anyway
connect the front-panel directly to the circuit ground. This violates
Rule 3.19, but is in my opinion good anyway.
At the same time it means that the R//C on both sides are not useful.
- Consider removing C5//R1 and C37/R98 to reduce the BOM (only place where 22nF is used).
- In this case still connect the mounting holes of the front-panel directly or via 0 Ohm to Gnd as it may give a better connection than the contact via the SMC connectors.