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Silicon Laboratories EFR32MG12, Reference Manual

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4.  RF Section

4.1  Introduction

This section gives a short introduction to the RF section of the BRD4173A Radio Board.

4.2  Schematic of the RF Matching Network

The schematic of the RF section of the BRD4173A Radio Board is shown in the following figure.

GND

GND

GND

PAVDD

VDCDC

GND

GND

GND

GND

VBIAS

GND

GND

GND

GND

VBIAS

C1

C102

100P

L4

L5

C8

P2

U.FL

3

2

1

L7

C9

Ground

RF I/O

RF Crystal

RF Analog Power

PA Power

U1B
EFR32

2G4RF_IOP

20

2G4RF_ION

19

RFVDD

9

HFXI

10

HFXO

11

PAVDD

21

RFVSS

17

PAVSS

18

SUBGRF_OP

13

SUBGRF_ON

14

SUBGRF_IP

15

SUBGRF_IN

16

C103

10P

TP1

L6

BAL1

ATB2012-50011

1

4

3

2

X1
38.400 MHz

3

1

2

4

P1

SMA

3

2

1

4

5

C7

C106

220N

R2

0R

NM

L8

C3

C107

10P

R1

0R

L9

C14

C4

C10

AT1

INVERTED_F

L102

BLM18AG601SN1

1

2

C11

L1

C6

C12

L103

BLM18AG601SN1

1

2

L3

C5

50R_R1

50R_UFL

50R_IFA

50R_SMA

Sub-GHz Matching Network

TRX Matching & 

Filter

Inverted-F 

Antenna

UFL 

Connector

TRX Matching

2.4 GHz Matching Network

Path Selection

Supply Filtering

High Frequency

Crystal

Sub-GHz PA

Power Supply

Filter

Discrete Balun

SMA

Connector

Figure 4.1.  Schematic of the RF Section of the BRD4173A

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 10 dBm at 434 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 lower output powers (under 13 dBm) additional harmonic filtering is not required as the harmonic levels are below the regu-
lation limits (see section 

7.1 Conducted Power Measurements

). Therefore, the matching network comprises only a two-element impe-

dance matching circuitry. The targeted output power is 10 dBm.

For conducted measurements the output of the matching network can also be connected to the UFL connector by relocating the series
R1 resistor to the R2 resistor position between the output of the matching and the UFL connector.

4.3  RF Section Power Supply

On  the  BRD4173A  Radio  Board  the  supply  for  the  radio  (RFVDD)  and  the  sub-GHz  and  2.4  GHz  power  amplifiers  (SUBGRF_ON,
SUBGRF_OP  and  PAVDD  pins)  is  connected  to  the  on-chip  DC-DC  converter.  This  way,  by  default,  the  DC-DC  converter  provides
1.8 V for the entire RF section (for details, see the schematic of the BRD4173A).

4.4  Bill of Materials for the sub-GHz Matching

The Bill of Materials of the sub-GHz matching network of the BRD4173A Radio Board is shown in the following table.

BRD4173A Reference Manual

RF Section

silabs.com

 | Building a more connected world.

Rev. 1.00  |  8

Summary of Contents for EFR32MG12

Page 1: ...l features from Expansion Boards With the supporting Simplicity Studio suite of tools developers can take advantage of graphical wireless application development mesh networking debug and packet trace and visual energy profiling and optimization The board also serves as an RF reference design for applications targeting 2 4 GHz and 434 MHz dual band wireless operation with 10 dBm output power RADIO...

Page 2: ...1 Introduction 8 4 2 Schematic of the RF Matching Network 8 4 2 1 Description of the Sub GHz RF Matching 8 4 2 2 Description of the 2 4 GHz RF Matching 8 4 3 RF Section Power Supply 8 4 4 Bill of Materials for the sub GHz Matching 8 4 5 Bill of Materials for the 2 4 GHz Matching 9 4 6 Inverted F Antenna 9 5 Mechanical Details 11 6 EMC Compliance 12 6 1 Introduction 12 6 2 EMC Regulations for 434 M...

Page 3: ...2 2 Radiated Measurements in the 2 4 GHz Band 17 8 EMC Compliance Recommendations 18 8 1 Recommendations for 434 MHz ETSI EN 300 220 1 Compliance 18 8 2 Recommendations for 2 4 GHz ETSI EN 300 328 Compliance 18 8 3 Recommendations for 2 4 GHz FCC 15 247 Compliance 18 9 Board Revision History 19 10 Errata 20 11 Document Revision History 21 silabs com Building a more connected world Rev 1 00 3 ...

Page 4: ...ed to operate in the European ETSI 433 05 434 79 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 for operating at 10 dBm output power To develop and or evaluate the EFR32 Mighty Gecko the BRD4173A Radio Board can be connected to the Wireless Starter Kit Main board to ...

Page 5: ...B_VREG F7 PA1 VCOM RX_MISO F5 PA5 VCOM_ENABLE F3 PF3 DEBUG TDI F1 PF0 DEBUG TCK_SWCLK P45 NC P43 NC P41 NC P39 NC P37 PD15 DISP_ENABLE SENSOR_ENABLE F11 PF5 UIF_LED1 F13 PF7 UIF_BUTTON1 F15 PC8 DISP_SCLK F17 PD14 DISP_SCS F19 PB13 PTI SYNC F21 PB11 PTI CLK GND VMCU_IN VCOM CTS_SCLK PA2 P0 P201 Lower Row VCOM RTS_ CS PA3 P2 UIF_BUTTON0 PF6 P4 UIF_BUTTON1 PF7 P6 GND VRF_IN P35 PD15 DISP_ENABLE SENSO...

Page 6: ...ceiver with output power up to 19 dBm For additional information on the EFR32MG12P433F1024GM48 refer to the EFR32MG12 data sheet 3 3 2 LF Crystal Oscillator LFXO The BRD4173A Radio Board has a 32 768 kHz crystal mounted For details regarding the crystal configuration refer to Application Note AN0016 1 Oscillator Design Considerations 3 3 3 HF Crystal Oscillator HFXO The BRD4173A Radio Board has a ...

Page 7: ...ries 0 Ohm resistor which is not mounted by default For conducted measure ments through the UFL connector the series component to the antenna should be removed and the 0 Ohm resistor should be mounted see section 4 2 2 Description of the 2 4 GHz RF Matching for further details 3 3 8 Radio Board Connectors Two dual row 0 05 pitch polarized connectors make up the BRD4173A Radio Board interface to th...

Page 8: ...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 10 dBm at 434 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 b...

Page 9: ...of the 2 4 GHz matching network of the BRD4173A Radio Board is shown in the following table Table 4 2 Bill of Materials for the BRD4173A 2 4GHz RF Matching Network Component Name Value Manufacturer Part Number L1 1 9 nH Murata LQP15MN1N9W02D C1 1 5 pF Murata GRM1555C1H1R5WA01D 4 6 Inverted F Antenna The BRD4173A Radio Board includes an on board printed inverted F antenna tuned for the 2 4 GHz band...

Page 10: ...re 4 2 Impedance and Reflection of the Inverted F Antenna of the BRD4173A Board Measured from the Matching Output BRD4173A Reference Manual RF Section silabs com Building a more connected world Rev 1 00 10 ...

Page 11: ... 6 mm 4 4 mm 2 4 GHz Path Selection DC DC Supply Filter Caps Serial Flash DC DC Inductor 2 4 GHz Matching 0 Figure 5 1 BRD4173A Top View 24 mm 27 3 mm 28 6 mm 5 mm Interface Connector Interface Connector 15 mm Board Identification PAVDD Supply Selection Display Enable Selection WSTK Sensor Enable Selection Figure 5 2 BRD4173A Bottom View BRD4173A Reference Manual Mechanical Details silabs com Buil...

Page 12: ...imits are also applied both for conducted and radiated measurements 6 3 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 specific limit is 30 dBm EIRP 6 4 FCC15 247 Emission Limits for the 2400 2483 5 MHz Band FCC 15...

Page 13: ...mits can be estimated based on the conducted measurement by assuming the use of an antenna with 0 dB gain at the fundamental and the harmonic frequencies The overall applied limits are shown in the table below Table 6 2 Applied Limits for Spurious Emissions for the 2 4 GHz Band Harmonic Frequency Limit 2nd 4800 4967 MHz 37 6 dBm 3rd 7200 7450 5 MHz 37 6 dBm 4th 9600 9934 MHz 30 dBm 5th 12000 12417...

Page 14: ...ip DCDC converter for the sub GHz PA it was provided as VBIAS through the discrete balun for details see the schematic of the BRD4173A The transceiver was operated in continuous carrier transmission mode The output power of the radio was set to 10 dBm The typical output spectrum is shown in the following figure Figure 7 1 Typical Output Spectrum of the BRD4173A As shown in the figure the fundament...

Page 15: ...us carrier transmission mode The output power of the radio was set to 10 dBm The typical output spectrum is shown in the following figure Figure 7 2 Typical Output Spectrum of the BRD4173A As shown in the figure the fundamental is very close to 10 dBm and all of the unwanted emissions are under the 37 6 dBm applied limit Note The conducted measurement is performed by connecting the on board UFL co...

Page 16: ...anes are illustrated in the figure below Figure 7 3 Illustration of Reference Planes with a Radio Board Plugged into the Wireless Starter Kit Mainboard 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 and so on Therefore the absolute le...

Page 17: ...se floor As shown in the table the fundamental is below the regulation limit by 2 5 dB the harmonic levels are also compliant with large mar gins 7 2 2 Radiated Measurements in the 2 4 GHz Band For the transmitter antenna the on board printed inverted F antenna of the BRD4173A Radio Board was used the R1 resistor was mounted The supply for the RF section RFVDD and the 2 4 GHz power amplifier PAVDD...

Page 18: ...e ETSI EN 300 328 regulation in both the conducted and radiated measurements The harmonic emissions are under the 30 dBm limit with a large margin Although the BRD4173A Radio Board has an option for mounting a shielding can it is not required for the compliance 8 3 Recommendations for 2 4 GHz FCC 15 247 Compliance As shown in the previous section the power of the fundamental of the BRD4173A Mighty...

Page 19: ...e The silkscreen marking on the board e g PCBxxxx A00 denotes the revision of the PCB The revision of the actual Radio Board is laser printed in the Board Info field on the PCB Also it can be read from the on board EEPROM BRD4173A Reference Manual Board Revision History silabs com Building a more connected world Rev 1 00 19 ...

Page 20: ...10 Errata There are no known errata at present BRD4173A Reference Manual Errata silabs com Building a more connected world Rev 1 00 20 ...

Page 21: ...11 Document Revision History Revision 1 00 June 2018 Initial document revision BRD4173A Reference Manual Document Revision History silabs com Building a more connected world Rev 1 00 21 ...

Page 22: ... or express copyright licenses granted hereunder to design or fabricate any integrated circuits The products are not designed or authorized to be used within any Life Support System without the specific written consent of Silicon Labs A Life Support System is any product or system intended to support or sustain life and or health which if it fails can be reasonably expected to result in significan...

Page 23: ...Mouser Electronics Authorized Distributor Click to View Pricing Inventory Delivery Lifecycle Information Silicon Laboratories SLWRB4173A ...

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