GRM1555C1H560GA01 [SILICON]
EFR32FG 2.4 GHz / 915 MHz Dual Band 19.5 dBm Radio Board BRD4250A Reference Manual;
| 型号： | GRM1555C1H560GA01 |
| 厂家： | 
SILICON |
| 描述： | EFR32FG 2.4 GHz / 915 MHz Dual Band 19.5 dBm Radio Board BRD4250A Reference Manual |
| 文件： | 总21页 (文件大小：1894K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EFR32FG 2.4 GHz / 915 MHz Dual Band
19.5 dBm Radio Board
BRD4250A Reference Manual
The EFR32FG family of Wireless SoCs deliver a high perform-
RADIO BOARD FEATURES
ance, low energy wireless solution integrated into a small form
factor package.
• Wireless SoC:
EFR32FG1P133F256GM48
By combining high performance sub-GHz RF and 2.4 GHz RF transceivers with an en-
ergy efficient 32-bit MCU, the family provides designers the ultimate in flexibility with a
family of pin-compatible devices that scale from 128/256 kB of flash and 16/32 kB of
RAM. The ultra-low power operating modes and fast wake-up times of the Silicon Labs
energy friendly 32-bit MCUs, combined with the low transmit and receive power con-
sumption of the sub-GHz and 2.4 GHz radios result in a solution optimized for battery
powered applications.
• CPU core: ARM Cortex-M4 with FFU
• Flash memory: 256 kB
• RAM: 32 kB
• Dual band transceiver integrated in the
Wireless SoC: EFR32
• Operation frequencies: 2.4 GHz
+ 915 MHz
• Transmit power: 19.5 dBm
To develop and/or evaluate the EFR32 Flex Gecko the BRD4250A Radio Board can be
connected to the Wireless Starter Kit Mainboard to get access to display, buttons and
additional features from Expansion Boards.
• 2.4 GHz: Integrated PCB antenna.
• 915 MHz: Single SMA connector both for
transmit and receive
• Crystals for LFXO and HFXO: 32.768 kHz
and 38.4 MHz.
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Introduction
1. Introduction
The EFR32 Flex Gecko Radio Boards provide a development platform (together with the Wireless Starter Kit Mainboard) for the Silicon
Labs EFR32 Flex Gecko Wireless System on Chips and serve as reference designs for the matching networks of the RF interfaces.
The BRD4250A Radio Board supports dual-band operation with its integrated sub-GHz ISM band and 2.4 GHz band transceivers. The
sub-GHz section is designed to the operate in the US FCC 902-928 MHz band with an external whip antenna, the 2.4 GHz section is
designed to operate at the 2400-2483.5 MHz band with the on-board printed antenna. The matching networks are optimized to
19.5 dBm output power.
To develop and/or evaluate the EFR32 Flex Gecko the BRD4250A Radio Board can be connected to the Wireless Starter Kit Mainboard
to get access to display, buttons and additional features from Expansion Boards and also to evaluate the performance of the RF interfa-
ces.
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BRD4250A Reference Manual
Radio Board Connector
2. Radio Board Connector
2.1 Introduction
The board-to-board connector scheme allows access to all EFR32FG1 GPIO pins as well as the RESETn signal. For more information
on the functions of the available pin functions, we refer you to the EFR32FG1 Datasheet.
2.2 Radio Board Connector Pin Associations
The figure below shows the pin mapping on the connector to the radio pins and their function on the Wireless Starter Kit Mainboard.
P200
P201
Upper Row
Lower Row
VMCU_IN
P1 / PC6 / DISP_SI
P3 / PC7
P5 / PC8 / DISP_SCLK
P7 / PC9
P9 / PA0 / VCOM.TX_MOSI
P11 / PA1 /VCOM.RX_MISO
P13 / PC11
P15 / NC
P17 / NC
P19 / NC
P21 / NC
P23 / NC
P25 / NC
P27 / NC
P29 / NC
P31 / PD13 / DISP_EXTCOMIN
P33 / PD14 / DISP_SCS
P35 / PD15 / DISP_ENABLE
VRF_IN
3v3
NC / P36
NC / P38
NC / P40
NC / P42
GND
GND
P37 / PD15 / SENSOR_ENABLE VCOM.#CTS_SCLK / PA2 / P0
P39 / NC
P41 / NC
P43 / NC
VCOM.#RTS_#CS / PA3 / P2
UIF_BUTTON0 / PF6 / P4
UIF_BUTTON1 / PF7 / P6
UIF_LED0 / PF4 / P8
DEBUG.TDI / PF3 / P10
PC10 / P12
NC / P44
P45 / NC
DEBUG.TMS_SWDIO / PF1 / F0
DEBUG.TDO_SWO / PF2 / F2
DEBUG.RESET / RADIO_#RESET / F4
VCOM.TX_MOSI / PA0 / F6
VCOM.#CTS_SCLK / PA2 / F8
UIF_LED0 / PF4 / F10
UIF_BUTTON0 / PF6 / F12
DISP_ENABLE / PD15 / F14
DISP_SI / PC6 / F16
DISP_EXTCOMIN / PD13 / F18
PTI.DATA / PB12 / F20
USB_VBUS
F1 / PF0 / DEBUG.TCK_SWCLK
F3 / PF3 / DEBUG.TDI
F5 / PA5 / VCOM_ENABLE
F7 / PA1 / VCOM.RX_MISO
F9 / PA3 / VCOM.#RTS_#CS
F11 / PF5 / UIF_LED1
F13 / PF7 / UIF_BUTTON1
F15 / PC8 / DISP_SCLK
F17 / PD14 / DISP_SCS
F19 / PB13 / PTI.SYNC
F21 / PB11 / PTI.CLK
USB_VREG
PA4 / P14
VCOM_ENABLE / PA5 / P16
PTI.CLK / PB11 / P18
PTI.DATA / PB12 / P20
PTI.SYNC / PB13 / P22
DEBUG.TMS_SWCLK / PF0 / P24
DEBUG.TMS_SWDIO / PF1 / P26
DEBUG.TDO_SWO / PF2 / P28
NC / P30
UIF_LED1 / PF5 / P32
NC / P34
5V
GND
Board ID SDA
Board ID SCL
GND
Figure 2.1. BRD4250A Radio Board Connector Pin Mapping
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Radio Board Block Summary
3. Radio Board Block Summary
3.1 Introduction
This section gives a short introduction to the blocks of the BRD4250A Radio Board.
3.2 Radio Board Block Diagram
The block diagram of the BRD4250A Radio Board is shown in the figure below.
I2C
GPIO
UART
Debug
UFL
Connector
Matching
Network &
Path
Inverted-F
2.4 GHz RF
2.4 GHz RF
SubGHz RF
PCB
AEM
Selection
Antenna
Radio
Packet Trace
SPI
EFR32
Wireless SoC
Board
Matching
Network &
DC Bias
Connectors
SubGHz RF
SMA
Connector
38.4M
32.768k
8 Mbit
24AA0024
MX25R
LF
Crystal
HF
Crystal
Serial Flash
Serial EEPROM
Figure 3.1. BRD4250A Block Diagram
3.3 Radio Board Block Description
3.3.1 Wireless MCU
The BRD4250A EFR32 Flex Gecko Radio Board incorporates an EFR32FG1P133F256GM48 Wireless System on Chip featuring 32-bit
Cortex-M4 with FFU core, 256 kB of flash memory 32 kB of RAM, an integrated 2.4 GHz band and an integrated sub-GHz ISM band
transceiver with output power up to 19.5 dBm. For additional information on the EFR32FG1P133F256GM48, refer to the EFR32FG1
Data Sheet.
3.3.2 LF Crystal Oscillator (LFXO)
The BRD4250A Radio Board has a 32.768 kHz crystal mounted.
3.3.3 HF Crystal Oscillator (HFXO)
The BRD4250A Radio Board has a 38.4 MHz crystal mounted.
3.3.4 Matching Network for Sub-GHz
The BRD4250A Radio Board incorporates a sub-GHz matching network which connects both the sub-GHz TX and RX pins of the
EFR32FG1 to the one SMA connector to be able to transmit and receive with one antenna. The component values were optimized for
the 915 MHz band RF performace and current consumption with 19.5 dBm output power.
For detailed description of the matching network see Chapter 4.2.1 Description of the Sub-GHz RF Matching.
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Radio Board Block Summary
3.3.5 Matching Network for 2.4 GHz
The BRD4250A Radio Board incorporates a 2.4 GHz matching network which connects the 2.4 GHz TRX pin of the EFR32FG1 to the
one on-board printed Inverted-F antenna. The component values were optimized for the 2.4 GHz band RF performace and current con-
sumption with 19.5 dBm output power.
For detailed description of the matching network see Chapter 4.2.2 Description of the 2.4 GHz RF Matching.
3.3.6 Inverted-F Antenna
The BRD4250A Radio Board includes a printed Inverted-F antenna (IFA) tuned to have close to 50 Ohm impedance at the 2.4 GHz
band.
For detailed description of the antenna see Chapter 4.6 Inverted-F Antenna.
3.3.7 SMA connector
To be able to perform conducted measurements or mount external antenna for radiated measurements, range tests etc., Silicon Labs
added an SMA connector to the Radio Board. The connector allows an external 50 Ohm cable or antenna to be connected during de-
sign verification or testing.
3.3.8 UFL Connector
To be able to perform conducted measurements Silicon Labs added an UFL connector to the Radio Board. The connector allows an
external 50 Ohm cable or antenna to be connected during design verification or testing.
Note: By default the output of the matching network is connected to the printed Inverted-F antenna by a series component. It can be
connected to the UFL connector as well through a series 0 Ohm resistor which is not mounted by default. For conducted measurements
through the UFL connector the series component to the antenna should be removed and the 0 Ohm resistor should be mounted (see
Chapter 4.2 Schematic of the RF Matching Network for further details).
3.3.9 Radio Board Connectors
Two dual-row, 0.05” pitch polarized connectors make up the BRD4250A Radio Board interface to the Wireless Starter Kit Mainboard.
For more information on the pin mapping between the EFR32FG1P133F256GM48 and the Radio Board Connector refer to Chapter
2.2 Radio Board Connector Pin Associations.
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BRD4250A Reference Manual
RF Section
4. RF Section
4.1 Introduction
This section gives a short introduction to the RF section of the BRD4250A.
4.2 Schematic of the RF Matching Network
The schematic of the RF section of the BRD4250A Radio Board is shown in the following figure.
AT1
Path Selection
2.4 GHz Matching Network
L1
L2
R1
0R
Inverted-F
Antenna
C1
C2
INVERTED_F
R2
0R
NM
TRX Matching &
Filter
GND
U1B
EFR32
P2
3
RF Crystal
RF I/O
2G4RF_IOP
1
Test
Connector
10
20
19
2
High Frequency
Crystal
HFXI
U.FL
GND
Sub-GHz PA
Power Supply
2
4
VBIAS
X1
38.400 MHz
2G4RF_ION
VDCDC
11
9
GND
HFXO
C10
Discrete Balun
GND
BAL1
L102
Antenna
Supply Filtering
RF Analog Power
13
15
L3
SUBGRF_OP
SUBGRF_IP
1
2
4
2
1
5
Connector
RFVDD
BAL2
N/C
BIAS
SE
C3
P1
BLM18AG601SN1
Filter
C102
100P
C103
10P
VDCDC
VBIAS
2
3
L103
GND
PA Power
L6
L7
C5
1
2
21
6
3
1
L5
PAVDD
4
5
BLM18AG601SN1
C107
10P
C106
220N
C6
C7
C8
Ground
SMA
C4
18
17
16
14
GND
L4
PAVSS
SUBGRF_IN
SUBGRF_ON
BAL1
GND
TP1
0900BL15C050
RFVSS
GND
TRX Matching
GND
GND
Sub-GHz Matching Network
Figure 4.1. Schematic of the RF Section of the BRD4250A
The RF matching comprises two separate TX/RX matching networks: one for the sub-GHz RF path, the other for the 2.4 GHz RF path.
4.2.1 Description of the Sub-GHz RF Matching
The sub-GHz matching network connects the differential TX outputs and RX inputs of the sub-GHz RF port to the SMA connector while
transforming the impedances to 50 Ohm. Careful design procedure was followed to ensure that the RX input circuitry does not load
down the TX output path while in TX mode and that the TX output circuitry does not degrade receive performance while in RX mode.
The matching includes a differential impedance matching circuitry, a discrete balanced-unbalanced transformer and a filter section. The
targeted output power is 19.5 dBm at 915 MHz.
4.2.2 Description of the 2.4 GHz RF Matching
The 2.4 GHz matching connects the 2G4RF_IOP pin to the on-board printed Inverted-F Antenna. The 2G4RF_ION pin is connected to
ground. For higher output powers (13 dBm and above) beside the impedance matching circuitry it is recommended to use additional
harmonic filtering as well at the RF output. The targeted output power of the BRD4250A board is 19.5 dBm thus the RF output of the IC
is connected to the antenna through a four-element impedance matching and harmonic filter circuitry.
For conducted measurements the output of the matching network can also be connected to the UFL connector by relocating the series
R1 0 Ohm resistor to the R2 position between the output of the matching and the UFL connector.
4.3 RF Section Power Supply
On the BRD4250A Radio Board the supply pin of the radio (RFVDD) is connected directly ot the output of the on-chip DC-DC converter
while the supply for the sub-GHz and 2.4 GHz power amplifiers (VBIAS) is provided directly by the Motherboard. This way, by default,
the DC-DC converter provides 1.8 V for the RF analog section, the Motherboard provides 3.3 V for the PAs (for details, see the sche-
matic of the BRD4250A).
4.4 Bill of Materials for the sub-GHz Matching
The Bill of Materials of the sub-GHz matching network of the BRD4250A Radio Board is shown in the following table.
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RF Section
Table 4.1. Bill of Materials for the BRD4250A 915 MHz 19.5 dBm RF Matching Network
Component name
Value
Balun
1.8 pF
1.8 pF
3.9 pF
3.3 pF
5.6 pF
3.3 pF
56 pF
3.3 nH
3.3 nH
18 nH
10 nH
10 nH
Manufacturer
Johanson Technology
Murata
Part Number
BAL1
C3
C4
C5
C6
C7
C8
C10
L3
0900BL15C050
GRM1555C1H1R8WA01
GRM1555C1H1R8WA01
GRM1555C1H3R9WA01
GRM1555C1H3R3BA01
GRM1555C1H5R6BA01
GRM1555C1H3R3BA01
GRM1555C1H560GA01
LQW15AN3N3B80
Murata
Murata
Murata
Murata
Murata
Murata
Murata
L4
Murata
LQW15AN3N3B80
L5
Murata
LQW15AN18NG00
L6
Murata
LQW15AN10NJ00
L7
Murata
LQW15AN10NJ00
4.5 Bill of Materials for the 2.4 GHz Matching
The Bill of Materials of the 2.4 GHz matching network of the BRD4250A Radio Board is shown in the following table.
Table 4.2. Bill of Materials for the BRD4250A 2.4 GHz 19.5 dBm RF Matching Network
Component name
Value
2.0 pF
1.0 pF
1.8 nH
3.0 nH
Manufacturer
Murata
Part Number
C1
C2
L1
L2
GRM1555C1H2R0WA01
GRM1555C1H1R0WA01
LQP15MN1N8W02
Murata
Murata
Murata
LQP15MN3N0W02
4.6 Inverted-F Antenna
The BRD4250A Radio Board includes an on-board printed Inverted-F Antenna tuned for the 2.4 GHz band. Due to the design restric-
tions of the Radio Board the input of the antenna and the output of the matching network can't be placed directly next to each other thus
a 50 Ohm transmission line was necessary to connect them. The resulting impedance and reflection measured at the output of the
matcing network are shown in the following figure. As it can be observed the impedance is close to 50 Ohm (the reflection is better than
-10 dB) for the entire 2.4 GHz band.
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RF Section
Figure 4.2. Impedance and Reflection of the Inverted-F Antenna of the BRD4250A
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Mechanical Details
5. Mechanical Details
The BRD4250A EFR32 Flex Gecko Radio Board is illustrated in the figures below.
UFL
Connector
2.4 GHz Matching
and Filter
DC-DC
Inductor
LFXTAL
DC-DC
&
Supply
Filter
Caps.
RF Output
Selection
EFR32xx
Sub-GHz RF
Matching
Printed
Inverted-F
Antenna
30 mm
and Filter
Frame of
the
Optional
Shielding
Can
OTA
Flash
SMA Connector
HFXTAL
4.4 mm
38.6 mm
45 mm
Figure 5.1. BRD4250A Top View
5 mm
24 mm
Board
Display
Enable
Identification
Selection
27.3 mm
28.6 mm
WSTK
Sensor
Enable
PAVDD
Supply
Selection
15 mm
Selection
Interface
Connector
Interface
Connector
Figure 5.2. BRD4250A Bottom View
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EMC Compliance
6. EMC Compliance
6.1 Introduction
Compliance of the fundamental and harmonic levels is tested at the listed frequencies against the listed EMC regulations:
• 915 MHz:
• FCC 15.247
• 2.4 GHz:
• ETSI EN 300-328
• FCC 15.247
6.2 EMC Regulations for 915 MHz
6.2.1 FCC15.247 Emission Limits for the 902-928 MHz Band
FCC 15.247 allows conducted output power up to 1 Watt (30 dBm) in the 902-928 MHz MHz band. For spurious emmissions the limit is
-20 dBc based on either conducted or radiated measurement, if the emission is not in a restricted band. The restricted bands are speci-
fied in FCC 15.205. In these bands the spurious emission levels must meet the levels set out in FCC 15.209. In the range form
960 MHz to the frequency of the 10th harmonic it is defined as 0.5 mV/m at 3 m distance (equals to -41.2 dBm in EIRP).
In case of operating in the 902-928 MHz band from the first 10 harmonics only the 2nd and 7th harmonics don't fall into restricted bands
so for those the -20 dBc limit should be applied. For the rest of the harmonics the -41.2 dBm limit should be applied.
6.3 EMC Regulations for 2.4 GHz
6.3.1 ETSI EN 300-328 Emission Limits for the 2400-2483.5 MHz Band
Based on ETSI EN 300-328 the allowed maximum fundamental power for the 2400-2483.5 MHz band is 20 dBm EIRP. For the unwan-
ted emissions in the 1 GHz to 12.75 GHz domain the specified limit is -30 dBm EIRP.
6.3.2 FCC15.247 Emission Limits for the 2400-2483.5 MHz Band
FCC 15.247 allows conducted output power up to 1 Watt (30 dBm) in the 2400-2483.5 MHz band. For spurious emmissions the limit is
-20 dBc based on either conducted or radiated measurement, if the emission is not in a restricted band. The restricted bands are speci-
fied in FCC 15.205. In these bands the spurious emission levels must meet the levels set out in FCC 15.209. In the range from
960 MHz to the frequency of the 5th harmonic it is defined as 0.5 mV/m at 3 m distance (equals to -41.2 dBm in EIRP).
Additionally, for spurious frequencies above 1 GHz FCC 15.35 allows duty-cycle relaxation to the regulatory limits. For the EmberZNet
PRO the relaxation is 3.6 dB. So practically the -41.2 dBm limit can be modified to -37.6 dBm.
In case of operating in the 2400-2483.5 MHz band the 2nd, 3rd and 5th harmonics can fall into restricted bands so for those the
-37.6 dBm limit should be applied. For the 4th harmonic the -20 dBc limit should be applied.
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EMC Compliance
6.3.3 Applied Emission Limits for the 2.4 GHz Band
The above ETSI limits are applied both for conducted and radiated measurements.
The FCC restricted band limits are radiated limits only. Besides that, Silicon Labs applies those to the conducted spectrum i.e. it is as-
sumed that in case of a custom board an antenna is used which has 0 dB gain at the fundamental and the harmonic frequencies. In that
theoretical case, based on the conducted measurement, the compliance with the radiated limits can be estimated.
The overall applied limits are shown in the table below.
Table 6.1. Applied Limits for Spurious Emissions for the 2.4 GHz Band
Harmonic
2nd
Frequency
4800~4967 MHz
7200~7450.5 MHz
9600~9934 MHz
12000~12417.5 MHz
Limit
-37.6 dBm
-37.6 dBm
-30 dBm
3rd
4th
5th
-37.6 dBm
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RF Performance
7. RF Performance
7.1 Conducted Power Measurements
During measurements the BRD4250A Radio Board was attached to a Wireless Starter Kit Mainboard which was supplied by USB. The
voltage supply for the Radio Board was 3.3 V.
7.1.1 Conducted Measurements in the 915 MHz band
The BRD4250A Radio Board was connected directly to a Spectrum Analyzer through its SMA connector. The supply for the radio
(RFVDD) was 1.8 V provided by the on-chip DC-DC converter, the supply for the power amplifier (VBIAS) was 3.3 V provided by the
Motherboard (for details, see the schematic of the BRD4250A). The transceiver was operated in continuous carrier transmission mode.
The output power of the radio was set to 19.5 dBm.
The typical output spectrum is shown in the following figure.
Figure 7.1. Typical Output Spectrum of the BRD4250A
As it can be observed the fundamental is close to 19.5 dBm so it is compliant with the 30 dBm fundamental limit, the strongest unwan-
ted emission is the double-frequency harmonic but with only around -44 dBm level it is compliant with the corresponding limit (-20 dBc)
with large margin. The other unwanted emissions are under the Spectrum Analyzer noise level (<-60 dBm). So the conducted spectrum
is compliant with the regulation limits.
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RF Performance
7.1.2 Conducted Measurements in the 2.4 GHz band
The BRD4250A Radio Board board was connected directly to a Spectrum Analyzer through its UFL connector (the 0 Ohm resistor was
removed from the R1 position and was soldered to the R2 position). The supply for the radio (RFVDD) was 1.8 V provided by the on-
chip DC-DC converter, the supply for the power amplifier (VBIAS) was 3.3 V provided by the Motherboard (for details, see the schemat-
ic of the BRD4250A). The transceiver was operated in continuous carrier transmission mode. The output power of the radio was set to
19.5 dBm.
The typical output spectrum is shown in the following figure.
Figure 7.2. Typical Output Spectrum of the BRD4250A
As it can be observed the fundamental is slightly lower than 19.5 dBm limit and the strongest unwanted emission is the double-frequen-
cy harmonic but with its -46.81 dBm level it is under the -37.6 dBm applied limit with ~9 dB margin. So the conducted spectrum is com-
pliant with the applied limits.
Note: The conducted measurement is performed by connecting the on-board UFL connector to a Spectrum Analyzer through an SMA
Conversion Adapter (P/N: HRMJ-U.FLP(40)). This connection itself introduces approx. 0.3 dB insertion loss.
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RF Performance
7.2 Radiated Power Measurements
During measurements the BRD4250A Radio Board was attached to a Wireless Starter Kit Mainboard which was supplied by USB. The
voltage supply for the Radio Board was 3.3 V. The radiated power was measured in an antenna chamber by rotating the DUT in 360
degree with horizontal and vertical reference antenna polarizations in the XY, XZ and YZ cuts. The measurement axes are as shown in
the figure below.
Figure 7.3. DUT: Radio Board with the Wireless Starter Kit Mainboard (Illustration)
Note: The radiated measurement results presented in this document were recorded in an unlicensed antenna chamber. Also the radi-
ated power levels may change depending on the actual application (PCB size, used antenna etc.) therefore the absolute levels and
margins of the final application is recommended to be verified in a licensed EMC testhouse!
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BRD4250A Reference Manual
RF Performance
7.2.1 Radiated Measurements in the 915 MHz band
For the 915 MHz radiated power measurements an external whip antenna (P/N: ANT-915-CW-HWR-SMA) was used as a transmitter
antenna. It was connected to the SMA connector of the BRD4250A Radio Board. The supply for the radio (RFVDD) was 1.8 V provided
by the on-chip DC-DC converter, the supply for the power amplifier (VBIAS) was 3.3 V provided by the Motherboard (for details, see the
schematic of the BRD4250A). The transceiver was operated in continuous carrier transmission mode. The output power of the radio
was set to 19.5 dBm.
The measured radiated powers are shown in the table below.
Table 7.1. Maximums of the Measured Radiated Powers of BRD4250A at 915 MHz
915 MHz
EIRP [dBm]
20.0
Orientation
YZ/H
XZ/H
YZ/H
XZ/V
-/-
Margin [dB]
10.0
>30
Limit in EIRP [dBm]
Fundamental
2nd harmonic
3rd harmonic
4th harmonic
5th harmonic
30
-33.5
-20 dBc
-41.2
-47.1
5.9
-47.5
6.3
-41.2
<-50*
-45.8
-50.9
-49.6
>10
-41.2
6th harmonic
7th harmonic
8th harmonic
9th harmonic
YZ/V
YZ/H
XZ/H
-/-
4.6
-41.2
>30
-20 dBc
-41.2
8.4
<-50*
<-50*
>10
-41.2
10th harmonic
-/-
>10
-41.2
* Signal level is below the Spectrum Analyzer noise floor.
As it can be observed the fundamental is below the regulation limit by 10 dB, the harmonic levels are also compliant.
7.2.2 Radiated Measurements in the 2.4 GHz band
For the 2.4 GHz radiated power measurements the on-board printed Inverted-F antenna of the BRD4250A Radio Board was used (the
R1 resistor was mounted). The supply for the radio (RFVDD) was 1.8 V provided by the on-chip DC-DC converter, the supply for the
power amplifier (VBIAS) was 3.3 V provided by the Motherboard (for details, see the schematic of the BRD4250A). The transceiver was
operated in continuous carrier transmission mode. The output power of the radio was set to 19.5 dBm. During the measurement the
sub-GHz antenna (P/N: ANT-915-CW-HWR-SMA) was attached to the SMA connector.
The results are shown in the table below.
Table 7.2. Maximums of the Measured Radiated Powers of BRD4250A at 2.4 GHz
2.4 GHz
EIRP [dBm]
21.8
Orientation
XY/H
Margin [dB]
Limit in EIRP [dBm]
Fundamental
2nd harmonic
3rd harmonic
8.2
7.4
30
-45.0
YZ/V
-37.6
-37.6
<-50*
<-50*
<-50*
-/-
>10
4th harmonic
5th harmonic
-/-
-/-
>20
>10
-30
-37.6
* Signal level is below the Spectrum Analyzer noise floor.
As it can be observed, thanks to the ~2-3 dB gain of the on-board Inverted-F antenna, the level of the fundamental is higher than
19.5 dBm. The harmonic levels are comliant with the applied limits with large margins.
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BRD4250A Reference Manual
EMC Compliance Recommendations
8. EMC Compliance Recommendations
8.1 Recommendations for 915 MHz FCC 15.247 compliance
As it was shown in the previous chapter the BRD4250A EFR32 Flex Gecko Radio Board is compliant with the emission limits of the
FCC 15.247 regulation with 19.5 dBm output power. Although the BRD4250A Radio Board has an option for mounting a shielding can,
that is not required for the compliance.
8.2 Recommendations for 2.4 GHz ETSI EN 300-328 compliance
As it was shown in the previous chapter the radiated power of the fundamental of the BRD4250A EFR32 Flex Gecko Radio Board with
19.5 dBm output power exceeds the 20 dBm limit of the ETSI EN 300-328 regulation due to the high antenna gain so reduction of the
fundamental power is required by approx. 2 dB in order to comply. The harmonic emissions are under the -30 dBm limit with large mar-
gin even with 19.5 dBm output power. Although the BRD4250A Radio Board has an option for mounting a shielding can, that is not
required for the compliance.
8.3 Recommendations for 2.4 GHz FCC 15.247 compliance
As it was shown in the previous chapter the BRD4250A EFR32 Flex Gecko Radio Board is compliant with the emission limits of the
FCC 15.247 regulation with 19.5 dBm output power. Although the BRD4250A Radio Board has an option for mounting a shielding can,
that is not required for the compliance.
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BRD4250A Reference Manual
Document Revision History
9. Document Revision History
Table 9.1. Document Revision History
Revision Number
Effective Date
Change Description
1.0
20.05.2015
Initial release.
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BRD4250A Reference Manual
Board Revisions
10. Board Revisions
Table 10.1. BRD4250A Radio Board Revisions
Radio Board Revision
Description
A00
B00
Initial release.
Changing board design to support dual-band operation (915 MHz/2.4 GHz). Updating sub-GHz matching
network.
B01
Sub-GHz PA supplied from VBIAS (filtered PAVDD).
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Rev. 1.00 | 17
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Radio Board Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 Radio Board Connector Pin Associations. . . . . . . . . . . . . . . . . . . . . 2
3. Radio Board Block Summary . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2 Radio Board Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.3 Radio Board Block Description . . . . . . . . . . . . . . . . . . . . . . . . 3
3.3.1 Wireless MCU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.3.2 LF Crystal Oscillator (LFXO) . . . . . . . . . . . . . . . . . . . . . . . . 3
3.3.3 HF Crystal Oscillator (HFXO) . . . . . . . . . . . . . . . . . . . . . . . . 3
3.3.4 Matching Network for Sub-GHz . . . . . . . . . . . . . . . . . . . . . . . 3
3.3.5 Matching Network for 2.4 GHz. . . . . . . . . . . . . . . . . . . . . . . . 4
3.3.6 Inverted-F Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3.7 SMA connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3.8 UFL Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3.9 Radio Board Connectors . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. RF Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2 Schematic of the RF Matching Network . . . . . . . . . . . . . . . . . . . . . 5
4.2.1 Description of the Sub-GHz RF Matching . . . . . . . . . . . . . . . . . . . . 5
4.2.2 Description of the 2.4 GHz RF Matching . . . . . . . . . . . . . . . . . . . . 5
4.3 RF Section Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.4 Bill of Materials for the sub-GHz Matching . . . . . . . . . . . . . . . . . . . . 5
4.5 Bill of Materials for the 2.4 GHz Matching . . . . . . . . . . . . . . . . . . . . 6
4.6 Inverted-F Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Mechanical Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. EMC Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.2 EMC Regulations for 915 MHz . . . . . . . . . . . . . . . . . . . . . . . . 9
6.2.1 FCC15.247 Emission Limits for the 902-928 MHz Band . . . . . . . . . . . . . . . 9
6.3 EMC Regulations for 2.4 GHz . . . . . . . . . . . . . . . . . . . . . . . . 9
6.3.1 ETSI EN 300-328 Emission Limits for the 2400-2483.5 MHz Band . . . . . . . . . . . 9
6.3.2 FCC15.247 Emission Limits for the 2400-2483.5 MHz Band. . . . . . . . . . . . . . 9
6.3.3 Applied Emission Limits for the 2.4 GHz Band . . . . . . . . . . . . . . . . . .10
7. RF Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
7.1 Conducted Power Measurements . . . . . . . . . . . . . . . . . . . . . . .11
7.1.1 Conducted Measurements in the 915 MHz band . . . . . . . . . . . . . . . . .11
7.1.2 Conducted Measurements in the 2.4 GHz band . . . . . . . . . . . . . . . . . .12
Table of Contents 18
7.2 Radiated Power Measurements . . . . . . . . . . . . . . . . . . . . . . . .13
7.2.1 Radiated Measurements in the 915 MHz band . . . . . . . . . . . . . . . . . .14
7.2.2 Radiated Measurements in the 2.4 GHz band . . . . . . . . . . . . . . . . . .14
8. EMC Compliance Recommendations . . . . . . . . . . . . . . . . . . . . . 15
8.1 Recommendations for 915 MHz FCC 15.247 compliance . . . . . . . . . . . . . . .15
8.2 Recommendations for 2.4 GHz ETSI EN 300-328 compliance . . . . . . . . . . . . .15
8.3 Recommendations for 2.4 GHz FCC 15.247 compliance . . . . . . . . . . . . . . .15
9. Document Revision History . . . . . . . . . . . . . . . . . . . . . . . . . 16
10. Board Revisions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table of Contents 19
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