NXP Semiconductors FRDMKW36UG, Руководство пользователя, Страница: 6 / 28

3 Functional description
The four-layer board provides the KW36 with its required RF circuitry, 32 MHz reference oscillator crystal, and power supply with
a DC-DC converter including Bypass and Buck modes. The layout for this base-level functionality can be used as a reference
layout for your target board.
3.1 RF circuit
The FRDM-KW36 RF circuit provides an RF interface for users to begin application development. A minimum matching network
to the MCU antenna pin is provided through C50, C51 and L2 to match the printed F-antenna to a 50 Ω controlled line.
The RF matching is different depending of the RF output power targeted. In case of the maximum RF output power
is lower than +3.5 dBm, 2 components is recommended.
NOTE
This is the default mounting components on the FRDM-KW36.
In case of maximum RF output power is b3.5 dBm and +5 dBm, it’s recommended to use 3 components for the RF
matching.
Maximum RF output power <=+3.5 dBm
2 components RF matching
C50=0.8 pF, L2=4.7 nH, C51=DNP
Refer to
Figure 5 .
+3.5 dBm < Maximum RF output power < +5 dBm
3 components RF matching
C50=0.6 pF, L2=4.7 nH, C51=0.3 pF
Refer to
Figure 6 .
An optional SMA is located at J21. This is enabled by rotating the 10-pF capacitor in C55 to the location of C57. Figure 5 and
Figure 6 show the RF circuit in details.
NXP Semiconductors
Functional description
FRDM-KW36 Freedom Development Board User’s Guide, Rev. 4, 01/2020
User's Guide 6 / 28