Figure 12-13. PCB Stack-up for the Reference Board
12.1.2.1 Test Procedure for Ensuring Compliance
The following test procedure must be performed both at design verification stage and in production to ensure
compliance.
• Initiate Continuous Transmission in the appropriate modulation mode from the device, in other words, 868.3
MHz; BPSK-20 for European band and 914 MHz; BPSK-ALT-40 for North American band.
• Remove the 0Ω resistor mounted at L2 to isolate the PCB antenna and verify the RF power through conducted
measurement at pad1 of L2.
12.2
Routing Guidelines
It is critical to follow the recommendations listed below to achieve the best RF performance:
• Follow the RF trace design as highlighted in
RF Trace Layout Design Instructions
for leveraging the
ATSAMR30M18A certifications.
• In a four or higher layer PCB design, dedicate the layer immediately below the layer containing the
ATSAMR30M18A module for GND.
• Avoid routing any traces in the region on the top layer of the host board which will be directly below the module
area.
• Place GND polygon pour below the module covering the entire area. Do not have any breaks in this GND plane.
Place sufficient GND vias in this polygon pour for better RF performance.
For optimal performance, the GND plane of the host board must have an minimum area of:
• 30 mm x 35 mm (for chip antenna - 0900AT43A0070)
• 70 mm x 50 mm (for external antenna - W1910)
• 101 mm x 101 mm (for external antenna - ANT-916-CW-QW-SMA)
• Place at least one GND via next to the GND module pinout.
• The RF trace from RF OUT of the ATSAMR30M18A module to the antenna feed point must be 50Ω single
ended controlled impedance trace.
ATSAMR30M18A
Application Reference Design
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2018-2021 Microchip Technology Inc.
and its subsidiaries
Datasheet
DS70005384B-page 52