NINA-B50 series - Hardware integration manual
UBX-22021116 - R02
Design-in
Page 26 of 57
C1-Public
3.3
General layout guidelines
This section describes the best practice for the schematic design and circuit layout of the application.
3.3.1
Considerations for schematic design and PCB floor planning
•
Low frequency signals are generally not critical to the layout and designers should focus on the
higher speed buses. One exception to this general rule is when high impedance traces, such as
signals driven by weak pull resistors, might be affected by crosstalk. For these and similar traces,
a supplementary isolation of
4w
(four times the line width) from other buses is recommended.
•
Verify which interface bus requires termination and add series resistor terminations to these
buses.
•
Carefully consider the placement of the module with respect to antenna position and host
processor.
•
Verify the controlled impedance dimensions of the selected PCB stack-up. The PCB manufacturer
might be able to provide test coupons.
•
Verify that the power supply design and power sequence are compliant with module specifications,
as described in the module’s data sheet.
⚠
Take particular care not to place components close to the antenna area and follow the
recommendations from the antenna manufacturer to determine the safe distance between the
antenna and any other part of the system. Designers should also maximize the distance between
the antenna and high-frequency buses, like DDRs and related components, or consider the use of
an optional metal shield to reduce the potential interference picked up by the module antenna.
3.3.2
Component placement
•
Place the module such that it provides optimum RF performance. This includes short low loss
antenna connections and unobstructed antenna placement. For more information about the
module placement and other antenna considerations, see also
•
Place bypass capacitors as close as possible to the module. Prioritize the placement of capacitors
with the least capacitance so that these are closest to module pads. The supply rails must be
routed through the capacitors from the power supply to the supply pad on the module.
•
Do not place components close to the antenna area. Follow the recommendations of the antenna
manufacturer to determine distance of the antenna in relation to other parts of the system.
Designers should also maximize the distance of the antenna to High-frequency busses, like DDRs
and related components. Alternatively, consider an optional metal shield to reduce interferences
that might otherwise be picked up by the antenna and subsequently reduce module sensitivity.