NORA-W2 series - Hardware integration manual
UBX-22005177 - R01
Design-in
Page 13 of 61
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3
Design-in
Follow the design guidelines stated in this chapter to optimize the integration of NORA-W2 series
modules in the final application board.
3.1
Overview
Although all application circuits must be properly designed, there are several points that require
special attention during application design. A list of these points, in order of importance, follows:
•
Module antenna connection:
ANT
Pad
Antenna circuits affect the RF compliance of all applications that include the certification
schemes related to the module. To maintain compliance and subsequent certification of the
application design, it is important to observe the applicable parts of antenna schematic and layout
design described in
•
Module supply:
VCC
,
VCC_IO
, and
GND
pins.
Supply circuits can affect the RF performance. It is important to observe the schematic and layout
design for these supplies. See also
Modules normally includes several supply pins listed in the module’s Data sheet P
in out list.
•
High-speed interfaces:
UART
pins.
High-speed interfaces are a potential source of radiated noise that can affect the regulatory
compliance standards for radiated emissions. It is important to follow the schematic and layout
design recommendations described in the
General high-speed layout guidelines
•
System functions:
RESET_N
, GPIO and other System input and output pins
Careful utilization of these pins in the application design is required to guarantee for correct boot
up and system operation. Ensure that the voltage level is correctly defined during module boot. It
is important to follow the schematic and layout design recommendations described in the
•
Other pins:
LED
and NC pins.
Careful utilization of these pins is required to guarantee proper functionality. It is important to
follow the schematic and layout design recommendations described in the
3.2
RF interface
As the unit cannot be mounted arbitrarily, the placement should be chosen with consideration so that
it does not interfere with radio communication. The NORA-W256 module (that includes a PCB trace
antenna) cannot be mounted in a metal enclosure. No metal casing or plastics using metal flakes
should be used. Avoid metallic based paint or lacquer as well. NORA-W251 offers more freedom as
an external antenna can be mounted further away from the module.
⚠
According to the FCC regulations, the transmission line from the module antenna pin to the
antenna or antenna connector on the host PCB is considered part of the approved antenna design.
Therefore, module integrators must either follow exactly one of the antenna reference designs
used in the module’s FCC type approval or certify their own designs.
3.2.1
Antenna integration
At the start the application design phase, when the mechanical design and the physical dimensions
of the board are still under analysis/decision, the antenna integration shall be considered. Apart from
the product’s performance the compliance and subsequen
t certification of the RF design depends
heavily on the radiating performance of the antennas.
