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mosaic-X5 Integration
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•
The SDIO, RMII and MDIO signals of mosaic-x5 can cause harmful radiated
interference if not properly routed. In designs with a collocated antenna, these
signals shall preferably be routed in an inner layer of the board, shielded by ground
planes or a ground copper pour at top and bottom layers, connected with stitching
vias. This approach puts them in a Faraday cage.
•
The same holds for other high-speed digital signals in other electronics on the
motherboard, like memory busses and clock signals. They should also be routed
in an inner layer, flanked with cupper pours connected to ground.
•
Large processor and memory chips sometimes already radiate via the bondwires
inside their package. Connectors like SD-card sockets and radio-module sockets
also tend to radiate.
It’s best to put these components at the side of the board
facing away from the collocated antenna. In this way the ground-layer will shield
them. Alternatively, they could be placed underneath an EMI shielding can. There
is less of a concern if the associated clock frequencies have no harmonics in the
GNSS bands.
See also Appendix C.
