NORA-W36 series - System integration manual
UBX-22021120 - R01
Design-in
Page 21 of 48
C1-Public
3.4.3
Layout and manufacturing
•
Avoid stubs on high-speed signals. Test points or component pads should be placed over the PCB
trace.
•
Verify the recommended maximum signal skew for differential pairs and length matching of buses.
•
Minimize the routing length; longer traces degrade signal performance. Ensure that the maximum
allowable length for high-speed buses is not exceeded.
•
Be sure to track your impedance matched traces. Consult early with your PCB manufacturer for
proper stack-up definition.
•
RF, analog, and digital sections should have dedicated and clearly separated areas on the board.
•
No digital routing is allowed in the GND reference plane area of RF traces (
ANT
pin and antenna).
•
Designers are strongly recommended to avoid digital routing beneath all layers of RF traces.
•
Ground cuts or separation are not allowed under the module.
•
As a first priority, minimize the length of the RF traces. Then, minimize bus length to reduce
potential EMI issues related to the radiation of 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. If designers need to change the
ground reference, some capacitors should be added and an adequate number of GND vias must
be added in the area of transition. This facilitates a low-impedance path between the two GND
layers for the return current.
•
Trace routing should maintain a distance that is greater than 3*W from the edge of the ground
plane routing.
•
Do
n’t
route power planes or traces in loops.
•
Route the power traces through both the bypass capacitor and bulk capacitor before connecting
to the module pin.
•
Power planes should maintain a safe distance from the edge of the PCB. The distance must be
sufficient to route a ground ring around the PCB, and the ground ring must then be stitched to
other layers through vias.
3.5
Module footprint and paste mask
shows the pin layout of NORA-W36 series modules. The proposed land pattern layout
complements the pin layout of the module. Both Solder Mask Defined (SMD) and Non-Solder Mask
Defined (NSMD) pins can be used with adherence to the following considerations:
☞
To help with the dissipation of the heat generated by the module, GND pads must have good
thermal bonding to PCB ground planes.
