NINA-B50 series - Hardware integration manual
UBX-22021116 - R02
Design-in
Page 22 of 57
C1-Public
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FR-4 dielectric material, although its high losses at high frequencies can be considered in RF
designs provided that:
o
RF trace length must be minimized to reduce dielectric losses.
o
If traces longer than few centimeters are needed, it is recommended to use a coaxial connector
and cable to reduce losses.
o
Stack-up should allow for thick 50
traces and at least 200 µm trace width is recommended
to assure good impedance control over the PCB manufacturing process.
o
FR-4 material exhibits poor thickness stability and thus less control of impedance over the
trace length. Contact the PCB manufacturer for specific tolerance of controlled impedance
traces.
•
The transmission lines width and spacing to the GND must be uniform and routed as smoothly as
possible: route RF lines in 45 °C angle or in arcs.
•
Add GND stitching vias around transmission lines.
•
Ensure solid metal connection of the adjacent metal layer on the PCB stack-up to main ground
layer, providing enough vias on the adjacent metal layer.
•
Route RF transmission lines far from any noise source (as switching supplies and digital lines) and
from any sensitive circuit to avoid crosstalk between RF traces and Hi-impedance or analog
signals.
•
Avoid stubs on the transmission lines, any component on the transmission line should be placed
with the connected pad over the trace. Also avoid any unnecessary component on RF traces.
3.2.3
NINA-B501
NINA-B501 is suited for designs that, due to mechanical integration or placement of the module,
require an external antenna.
At the beginning of the design phase, when the physical dimensions of the application board are under
analysis/decision, designers must take care of the antennas from all perspectives. RF compliance of
the device, integrating NINA-B501 module with all the applicable required certification schemes,
heavily depends on the radiating performance of the antennas. Designers are encouraged to consider
one of the u-blox suggested antennas and follow the layout requirements.
3.2.3.1
RF connector design
If an external antenna is required, designers should use a proper RF connector. It is the responsibility
of the designer to verify the compatibility between plugs and receptacles used in the design.
suggests several RF connector plugs that designers can use to connect RF coaxial cables
based on the declaration of the respective manufacturers.
Manufacturer
Series
Remarks
Hirose
U.FL® Ultra Small Surface Mount Coaxial Connector
Recommended
I-PEX
MHF® Micro Coaxial Connector
Tyco
UMCC® Ultra-Miniature Coax Connector
Amphenol RF
AMC® Amphenol Micro Coaxial
Lighthorse Technologies, Inc. IPX ultra micro-miniature RF connector
Table 6: U.FL compatible plug connector
The Hirose U.FL-R-SMT RF receptacles (or similar parts) require a suitable mated RF plug from the
same connector series. Due to wide usage of this connector, several manufacturers offer compatible
equivalents. It is the responsibility of the designer to verify the compatibility between plugs and
receptacles used in the design.
