NORA-B1 series - System integration manual
UBX-20027617 - R02
Design-in
Page 33 of 58
C1-Public
4.8.3
Layout and manufacturing
•
Avoid stubs on high-speed signals. Even through-hole vias may have an impact on signal quality.
•
Verify the recommended maximum signal skew for differential pairs and length matching of
buses.
•
Minimize the routing length; longer traces will degrade signal performance. Ensure that the
maximum allowable length for high-speed buses is not exceeded.
•
Ensure that impedance matched traces are correctly routed. Consult with the PCB manufacturer
early in the project for proper stack-up definition.
•
RF and digital sections should be clearly separated on the board.
•
Ground splitting is not allowed below the module.
•
Minimize the bus length to reduce potential EMI issues from digital buses.
•
All traces (including low speed or DC traces) must couple with a reference plane (
GND
or power);
high-speed buses should be referenced to the ground plane. In this case, if the designer needs to
change the ground reference, an adequate number of
GND
vias must be added near the transition
to provide a low impedance path between the two
GND
layers for the return current.
•
High-speed buses are not allowed to change reference plane. If a reference plane change is
unavoidable, some capacitors should be added in the area to provide a low impedance return path
through the different reference planes.
•
Trace routing should keep a distance greater than 3w from the ground plane routing edge.
•
Power planes should keep a distance from the PCB edge that is sufficient to route a ground ring
around the PCB. The ground ring must then be connected to other layers through vias. The ground
ring must not violate the antenna keep-out areas.
4.9
Module footprint and paste mask
The mechanical outline of the NORA-B1 series module can be found in the NORA-B1 series data
sheet [1]. The proposed land pattern layout reflects the pad’s layout of the module.
The Non Solder Mask Defined (NSMD) pad type is recommended over the Solder Mask Defined (SMD)
pad type, which implements the solder mask opening 50
μ
m larger per side than the corresponding
copper pad.
The suggested paste mask layout for the NORA-B1 series modules is to follow the same pad layout
1:1 as described in the NORA-B1 series data sheet [1].
⚠
These are recommendations only and not specifications. The exact mask geometries, distances,
and stencil thicknesses must be adapted to the specific production processes of the customer.
4.10
Thermal guidelines
NORA-B1 series modules have been successfully tested from –40 °C to +105 °C. Although NORA-B1
is a low power device that generates only a small amount of heat during operation, proper grounding
is necessary for temperature relief during high ambient temperatures.
4.11
ESD guidelines
The immunity of devices integrating NORA-B1 modules to Electrostatic Discharge (ESD) is part of the
Electromagnetic Compatibility (EMC) conformity, which is required for products bearing the CE
marking, compliant with the R&TTE Directive (99/5/EC), the EMC Directive (89/336/EEC) and the Low
Voltage Directive (73/23/EEC) issued by the Commission of the European Community.
