Texas Instruments | Matched Filter Balun for CC1352 and CC1352P (Rev. A) | Application notes | Texas Instruments Matched Filter Balun for CC1352 and CC1352P (Rev. A) Application notes

Texas Instruments Matched Filter Balun for CC1352 and CC1352P (Rev. A) Application notes
Application Report
SWRA629A – October 2018 – Revised June 2019
Integrated Filter Balun for CC1352
Richard Wallace
ABSTRACT
This application report describes the matched-balun filter components that have been specifically
designed for the CC1352R [1] and CC1352P [2] operating in the 868 MHz, 915 MHz, 920 MHz and 2.4
GHz ISM bands.
1
2
3
4
5
Contents
Introduction ................................................................................................................... 2
Reference Designs Available............................................................................................... 3
IPC Measurement Results ................................................................................................ 13
Summary .................................................................................................................... 21
References .................................................................................................................. 22
List of Figures
...............................................................................................
1
CC1352EM-IPC Rev1.1 EM
2
CC1352P LaunchPad RF Frontend Discrete Component Concept ................................................... 4
3
JTI CC1352 IPC Equivalent Circuit for 863-930 MHz and 2.4 GHz
4
Murata CC1352 IPC Equivalent Circuit for 863-930 MHz & 2.4 GHz................................................. 6
5
CC1352 IPC RF Frontend With SPDT Switch for 863-930 MHz and 2.4 GHz ...................................... 6
6
Component Size and Dimensions ......................................................................................... 7
7
Size Comparison Between the IPC and Discrete Design .............................................................. 7
8
Component Placement ...................................................................................................... 8
9
Distance Between CC1352 and IPC and Via Placement
10
Layer 1 ....................................................................................................................... 10
11
Layer 2 ....................................................................................................................... 11
12
Layer 3 ....................................................................................................................... 12
13
Layer 4 ....................................................................................................................... 13
14
Sub-1 GHz Output Power vs Frequency ................................................................................ 14
15
Sub-1 GHz Sensitivity vs Frequency .................................................................................... 14
16
Sub-1 GHz Link Budget vs Frequency .................................................................................. 14
17
868 MHz Output Power vs PA Setting
18
19
20
21
22
23
24
25
26
27
..................................................
..............................................................
..................................................................................
868 MHz Tx Current vs PA Setting ......................................................................................
868 MHz Tx Efficiency vs PA Setting....................................................................................
868 MHz 2nd Harmonic vs PA Setting ..................................................................................
868 MHz Tx 3rd Harmonic vs PA Setting ...............................................................................
868 MHz 4th Harmonic vs PA Setting ...................................................................................
868 MHz Tx 5th Harmonic vs PA Setting ...............................................................................
Murata - 868 MHz ETSI EN300 220 Radiated Emissions at Max Output Power ..................................
JTI - 868 MHz ETSI EN300 220 Radiated Emissions at Max Output Power ......................................
2.4 GHz Output Power v Frequency .....................................................................................
2.4 GHz 1 Mbps BLE Sensitivity v Frequency .........................................................................
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5
9
15
16
16
16
17
17
17
19
19
19
20
1
Introduction
28
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2.4 GHz 1 Mbps BLE Link Budget v Frequency
.......................................................................
20
List of Tables
1
Acronyms Used in This Document ........................................................................................ 3
2
ETSI and FCC Limits for Harmonic Radiation .......................................................................... 17
3
FCC Correction Factor and Maximum Duty Cycling ................................................................... 18
4
Summary of Link Budget at Maximum Output Power ................................................................. 21
Trademarks
All trademarks are the property of their respective owners.
1
Introduction
With the matched-balun filter component; the component count is significantly reduced whilst still obtaining
the high radio performance.
The matched-filter balun component is commonly designated as an Integrated Passive Component (IPC).
23 passives are required at the CC1352R RF ports. With the IPC, the component count is reduced from
23 to 3 components which saves space and reduces pick-and-place assembly costs.
CC1352R IPC can also be used in the same manner with the CC1352P which has an additional RF port
with a high power PA.
The IPC is available for CC1352R and CC1352P and is available from two different vendors, Johanson
Technology (part number: 0900PC15A0036) [4] and Murata (part number: LFB21868MDZ5E757) [5].
These parts share a common footprint and pinout.
The size for the matched balun filter component is only 2.0 mm x 1.25 mm (EIA 0805, Metric 2012)
therefore it is recommended for compact designs.
All measurement results presented in this document are based on measurements performed on the
CC1352R EM Rev 1.1 Reference Design [6], unless otherwise specified.
The comparison performance and benefits of the JTI IPC and the Murata IPC are explained in this
document.
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Introduction
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Figure 1. CC1352EM-IPC Rev1.1 EM
1.1
Acronyms Used in This Document
Table 1. Acronyms Used in This Document
Acronym
2
Description
DC
Direct Current
EM
Evaluation Module
ETSI
European Telecommunications Standards Institute
FCC
Federal Communications Commission
FR4
Material Type Used for Producing PCB
ISM
Industrial, Scientific, Medical
JTI
Johanson Technology
LC
Inductor (L) Capacitor (C) Configuration
ML
Multi-Layer Inductor
NM
Not Mounted
PCB
Printed Circuit Board
SoC
System on Chip
SRD
Short Range Devices
WW
Wire-Wound Inductor
Reference Designs Available
The existing reference designs for CC1352R [3] and CC1352P are based upon passive discrete
components, see Figure 2. Each RF port is terminated with 50 Ω impedance that can be connected to
SMA connector, switch or diplexer. The main advantage with using a switch or diplexer is a common RF
port instead of several RF ports.
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Reference Designs Available
2.1
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CC1352x Discrete Reference Design
CC1352R has two RF ports and CC1352P has three RF ports. The additional RF port in CC1352P is a
high power PA that can only be configured as a Tx port. The CC1352 IPC can be used for both CC1352R
and CC1352P.
The decoupling capacitors C41 and C51 are relatively large values to integrate into a small compact
ceramic package so these components will still be required with the IPC.
A SP3T switch is used on the high power PA LaunchPads to enable a common RF port which is then
connected to an integrated PCB dual-band antenna.
The components values are not shown in Figure 2 since these are dependent on the choice of frequency
of each RF port. Each RF port can be configured to operate in a specific ISM band (315 MHz, 430-510
MHz, 863-930 MHz or 2.4 GHz).
Configuration of the Rx_Tx pin allows for external biasing or internal biasing of the LNA when operating in
Rx mode. Theoretically, with external biasing of the LNA, the sensitivity can be improved providing that the
external biasing inductance has lower losses than the internal biasing inductance.
RX_TX
P11
C492
1
L12
M1
2
M2
DNM
4
C491
47pF
5
J7
1
3
2
C483
DNM
U32
RX_TX
P12
C37
DIO28_RF_2G4
DIO30_RF_SUB1G
DIO29_RF_PA
7
6
3
EGP
RF3
RF2
RF1
V3
V2
V1
SKY13317-373
1
RFC
NC
1
2
CR13
TPD1E0B04DPY
DNM
1
1
2
3
4
5
6
7
8
5
4
100pF
RX_TX
M1
2
M2
2_4_GHZ_RF_P
2_4_GHZ_RF_N
SUB-1_GHZ_RF_P
SUB-1_GHZ_RF_N
TX_20DBM_P
TX_20DBM_N
RX_TX
C36
9
2
C31
100pF
CC1352P1F3RGZ
Z60
A1
Z63
1
Z61
Z62
P13
1
VDDS
DNM
M1
2
M2
Z60-Z63 for
antenna matching
Figure 2. CC1352P LaunchPad RF Frontend Discrete Component Concept
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2.2
CC1352 IPC
The objectives with the IPC compared to the discrete design:
• Reduce the amount of external components required
• Reduce the overall size, more compact
• Reduced component count so the layout process is easier and less prone to RF cross-talk due to poor
RF layouts
• Flexibility to change IPC to different versions to enable different frequencies
• Common footprint and pinout for all IPCs
• Maintain RF performance of discrete design
2.2.1
JTI CC1352 IPC Equivalent Circuit
The equivalent circuit of the IPC from Johanson Technology (JTI) is shown in Figure 3. The complete
specification of their IPC is available from the Johanson Technology web site [1].
JTI’s matched balun filter solution implementation just requires two external DC blocking components
(C41 and C51). The JTI CC1352 IPC should be configured as external biasing for both sub-1 GHz and 2.4
GHz Rx operation.
Rx_Tx Bias Configuration:
2.4 GHz: External
Sub-1 GHz: External
12pF
RX_TX
2
2.4nH
1
1
1.1pF
1
15nH
2
1
1.5nH
2.4 GHz
2
2nH
12pF
2
1
2
1pF
2.4nH
1pF
C21
1.1pF
2_4_GHZ_RF_P
2_4_GHZ_RF_N
SUB-1_GHZ_RF_P
SUB-1_GHZ_RF_N
RX_TX
1
2
3
4
5
C41
100pF
RX_TX
1
External Cap
RX_TX
10nH
CC1352R1F3RGZ
1
2
2
863-930 MHz
1
3.9nH
C51
3pF
1
22nH
1.2pF
1
2
2
2
7.5nH
1
3.9nH
100pF
2
10nH
2.7pF
5.6pF
External Cap
3pF
Figure 3. JTI CC1352 IPC Equivalent Circuit for 863-930 MHz and 2.4 GHz
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Reference Designs Available
2.2.2
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Murata CC1352 IPC Equivalent Circuit
The equivalent circuit of the IPC from Murata is shown in Figure 4. The complete specification of their IPC
is available from Murata [5].
Murata’s matched balun filter solution implementation just requires two external DC blocking components
(C41 and C51). The Murata CC1352 IPC should be configured as external biasing for sub-1 GHz and as
internal biasing for 2.4 GHz Rx operation.
Figure 4. Murata CC1352 IPC Equivalent Circuit for 863-930 MHz & 2.4 GHz
Figure 5 shows the CC1352R IPC schematic with a common RF port. The sub-1 GHz RF port and 2.4
GHz RF port from the IPC are connected to the dual-through section of the SPDT switch. The single-pole
port of the switch can be connected to a single-feed dual-band antenna. The SPDT switch can be
controlled by any DIO. DIO30 is used in the CC1352R EM IPC EM design.
J1
4
SMA-10V21-TGG
3
5
2
1
U2
TR1
10
9
1
2
3
4
5
2_4_GHZ_RF_P
2_4_GHZ_RF_N
SUB-1_GHZ_RF_P
SUB-1_GHZ_RF_N
RX_TX
8
7
RX_TX
6
GND
UBP_2_4_GHZ
BP_2_4_GHZ_RF_P
GND
BP_2_4_GHZ_RF_N
GND
BP_SUB-1_GHZ_RF_P
UBP_SUB-1_GHZ
BP_SUB-1_GHZ_RF_N
Cc1352
IPC1352
RX_TX
1
4
PORT2
CTL
3
DIO_30
C21
2
5
3
GND
COMM_PORT
2
C41
VDDS
4
6
5
PORT1
VDD
1
100pF
XMSSJJ3G0PA-054
100pF
C51
100pF
Figure 5. CC1352 IPC RF Frontend With SPDT Switch for 863-930 MHz and 2.4 GHz
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2.2.3
CC1352 IPC Size and Dimensions
The physical size of the IPC and dimensions are shown in Figure 6. The dimension are only 2.00 mm x
1.25 mm which is similar in size as a 0805 (EIA size) or 2012 (metric size) footprint. This makes the IPC
ideal for compact designs and makes the layout much easier and less risk for RF layout issues. The
layout size comparison between the IPC and the discrete design is shown in Figure 7.
Figure 6. Component Size and Dimensions
Figure 7. Size Comparison Between the IPC and Discrete Design
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Reference Designs Available
2.2.4
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CC1352 IPC Reference Design
2.2.4.1
Component Placement and Layout
The IPC component placement influences the RF performance and the reference design should be
followed as close as possible [6]. For more information, see Figure 8 and Figure 9. The distance between
the IPC and the CC1352 is important and this should be 1.26 mm, see Figure 9.
In the event that the reference design [6] cannot be copied then the routing from the RF pins must be
symmetrical to the IPC. The length of the tracks should be kept to a minimum and preferably the same
recommended length that is used in the reference design of 1.26 mm. The width of the tracks between
CC1352 and the IPC should also be kept as 0.25 mm.
If the recommended distance of 1.26 mm, 0.25 mm track width or GND via placements are too far away
from the IPC, this will introduce phase shifts and additional parasitic inductance. Not following the
reference design will affect the Tx output power, Tx harmonic attenuation and Rx sensitivity. For
recommended GND via placements for the IPC, see Figure 9.
All component ground pads should have the own ground via which should be positioned as close as
possible to the ground pad. When positioning the ground vias for the component pad grounds it is
important to try to keep the return path loop to ground as little as possible in order to prevent unnecessary
radiated emissions.
DC blocking components C41 and C51 are 0201 passives. U2 is a compact SPDT switch that combines
the two RF ports into one common RF port. With one common RF port then a dual-band antenna can then
be added.
Figure 8. Component Placement
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Figure 9. Distance Between CC1352 and IPC and Via Placement
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2.2.4.2
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Layout, Layer 1
Figure 10 shows the top layer of the 4-layer reference design. Remaining area is filled with GND for
shielding purposes.
Figure 10. Layer 1
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2.2.4.3
Layout, Layer 2
Figure 11 shows the second layer of the 4-layer reference design. This layer is mainly a GND layer. It is
important to have a solid ground plane underneath the complete RF section and to avoid any routing
directly underneath the RF section. The reference design [6] has a thickness of 175 um between layer 1
and layer 2. This is the main parameter in the FR4 PCB stack-up that should be kept similar when copying
the reference design.
Figure 11. Layer 2
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Layout, Layer 3
Figure 12 shows the third layer of the 4-layer reference design. This layer is mainly for VDDS and VDDR
power. Remaining area is filled with GND for shielding purposes. The power routing should always be
routed to the decoupling capacitor first; then from the decoupling capacitor to the pad of the CC1352.
Figure 12. Layer 3
2.2.4.5
Layout, Layer 4
Figure 13 shows the fourth layer of the 4-layer reference design. This layer is mainly for the connector /
DIO distribution. Remaining area is filled with GND for shielding purposes.
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Figure 13. Layer 4
3
IPC Measurement Results
All results presented in this chapter are based on measurements performed on CC1352 EM Rev 1.1 [6],
unless otherwise noted. A minimum of four units have been measured in order to obtain an average result
which is presented in this report. All measurement results presented are the average of each batch tested
in room temperature from typical devices.
NOTE: All values are in dBm if not otherwise stated. All the measurements are measured at the
SMA connector after the switch. The switch has a typical insertion loss of 0.7 dB on the
reference design [6].
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IPC Measurement Results
3.1
3.1.1
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Sub-1 GHz
CC1352R Output Power, Sensitivity and Link Budget
Figure 14 shows the output power measurements across a frequency span from 863-950 MHz.
Summary: Murata has a higher output power than Johanson with maximum power settings (boost setting).
High output power across the entire 863-950 MHz frequency span.
14.5
Output Power (dBm)
14
13.5
13
12.5
12
11.5
11
863
Johanson
Murata
873
883
893 903 913 923
Frequency (MHz)
933
943 950
D014
Figure 14. Sub-1 GHz Output Power vs Frequency
Figure 15 shows the sensitivity measurements (50 kbps datarate) across a frequency span from 863-950
MHz.
Summary: Johanson has better sensitivity than Murata especially in the band from 900-950 MHz.
-105
Sensitivity (50 kbps, dbm)
-106
-107
-108
-109
-110
Johanson
Murata
-111
863
873
883
893 903 913 923
Frequency (MHz)
933
943 950
D015
Figure 15. Sub-1 GHz Sensitivity vs Frequency
Figure 16 shows the link budget that is the sum of the output power and the sensitivity measurements.
This is a main parameter for greater range
Summary: 863-899 MHz, both Johanson and Murata have a similar link budget. For 900-950 MHz, then
Johanson has a stronger link budget.
122.5
122
Link Budget (dB)
121.5
121
120.5
120
119.5
119
Johanson
Murata
118.5
118
863
873
883
893 903 913 923
Frequency (MHz)
933
943 950
D016
Figure 16. Sub-1 GHz Link Budget vs Frequency
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3.1.2
CC1352R Tx Efficiency, Tx Harmonics at Maximum Output Power (Boost)
3
•
•
•
•
•
•
•
•
•
•
•
•
•
•
3.1.3
V, Maximum output power setting; average results from 863-870 MHz:
JTI Tx Efficiency: 17.2 %
Murata Tx Efficiency: 21.0 %
JTI Tx Current: 29.6 mA
Murata Tx Current: 42.8 mA
JTI Tx Output Power: 11.8 dBm
Murata Output Power: 13.9 dBm
JTI 2nd Harmonic Level: -38.2 dBm
Murata 2nd Harmonic Level: -36.3 dBm
JTI 3rd Harmonic Level: -40.2 dBm
Murata 3rd Harmonic Level: -40.4 dBm
JTI 4th Harmonic Level: -60.9 dBm
Murata 4th Harmonic Level: -48.9 dBm
JTI 5th Harmonic Level: -37.5 dBm
Murata 5th Harmonic Level: -36.2 dBm
CC1352 Rx Current
3.6 V, -100 dBm signal generator RF:
• JTI Rx Current: 6.9 mA
• Murata Rx Current: 6.8 mA
3.1.4
CC1352R Tx Efficiency, Tx Harmonics and Tx Output at Various PA Settings
Figure 17 shows the output power against PA settings at 868 MHz.
Summary: Murata has optimized the output power level for the first three powers steps. The remaining
power steps, Johanson has higher output power than Murata.
16
Johanson
Murata
12
Output Power (dBm)
8
4
0
-4
-8
-12
-16
-20
-24
1216
1729
1730
3268
4295
4808
4809
5835
6348
7374
7302
8260
9798
12872
20557
36362
319
32831
-28
D017
Power Step Setting
Figure 17. 868 MHz Output Power vs PA Setting
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Figure 18 shows the Tx current against PA settings at 868 MHz
32
30
28
26
24
22
20
18
16
14
12
10
8
6
1216
1729
1730
3268
4295
4808
4809
5835
6348
7374
7302
8260
9798
12872
20557
36362
32831
Johanson
Murata
319
Current (mA)
Summary: Murata has optimized their output power level for the maximum output level with boost mode
and Johanson has optimized their output power level for the normal mode. Johanson has a lower current
Tx current consumption in the normal Tx mode than Murata.
D018
Power Step Setting
Figure 18. 868 MHz Tx Current vs PA Setting
Figure 19 shows the Tx efficiency against PA settings at 868 MHz.
Summary: Murata has optimized their Tx efficiency for the maximum output level with boost (max) mode
and Johanson has optimized their Tx efficiency for the normal mode. Figure 18 shows a significant
increase of current for Murata in the first steps but the efficiency is similar although Johanson has a
greater Tx efficiency for all power steps in the normal mode than Murata.
18
Johanson
Murata
16
Efficiency (%)
14
12
10
8
6
4
2
1216
1729
1730
3268
4295
4808
4809
5835
6348
7374
7302
8260
9798
12872
20557
319
36362
32831
0
D019
Power Step Setting
Figure 19. 868 MHz Tx Efficiency vs PA Setting
Figure 20 shows the 868 MHz 2nd harmonic against PA settings.
Summary: Similar performance.
-32
Output Power (dBm)
Johanson
Murata
-36
-40
-44
1216
1729
1730
3268
4295
4808
4809
5835
6348
7374
7302
8260
9798
12872
20557
36362
319
32831
-48
D020
Power Step Setting
Figure 20. 868 MHz 2nd Harmonic vs PA Setting
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Figure 21 shows the 868 MHz 3rd harmonic against PA settings
Summary: Similar performance.
-34
Output Power (dBm)
-36
-38
-40
-42
-44
-46
1216
1729
1730
3268
4295
4808
4809
5835
6348
7374
7302
8260
9798
12872
20557
36362
319
32831
-48
D021
Power Step Setting
Figure 21. 868 MHz Tx 3rd Harmonic vs PA Setting
Figure 22 shows the 868 MHz 4th harmonic against PA settings.
Summary: Similar performance.
-32
Johanson
Murata
Output Power (dBm)
-34
-36
-38
-40
-42
-44
-46
1216
1729
1730
3268
4295
4808
4809
5835
6348
7374
7302
8260
9798
12872
20557
36362
319
32831
-48
D022
Power Step Setting
Figure 22. 868 MHz 4th Harmonic vs PA Setting
Figure 23 shows the 868 MHz 5th harmonic against PA settings
Summary: Similar performance.
-34
Johanson
Murata
Output Power (dBm)
-36
-38
-40
-42
-44
-46
1216
1729
1730
3268
4295
4808
4809
5835
6348
7374
7302
8260
9798
12872
20557
36362
319
32831
-48
D023
Power Step Setting
Figure 23. 868 MHz Tx 5th Harmonic vs PA Setting
3.1.5
Overview of Harmonic Emission Regulatory Requirements
Table 2. ETSI and FCC Limits for Harmonic Radiation
Limit
fc
2nd Harmonic
3rd Harmonic
4th Harmonic
5th Harmonic
FCC 15.249
0 dBm
54 dBmV/m
54 dBmV/m
54 dBmV/m
54 dBmV/m
FCC 15.247
30 dBm
20 dBc
54 dBmV/m
54 dBmV/m
54 dBmV/m
ETSI EN 300 220
14 dBm
−30 dBm
−30 dBm
−30 dBm
−30 dBm
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The maximum harmonic level for ETSI EN 300 220 regulations for 868 MHz is -30 dBm and all tests
measurements are within this limit.
The programmed output power and the quality of the ground plane will affect the level of the harmonics
and thus determine the necessary duty cycling for FCC. Harmonic emission will also depend on the RF
layout and if there are any PCB traces / stubs acting as unwanted antennas emitting emissions.
Table 2 shows the FCC and ETSI limits. Above 1 GHz, FCC allows the radiation to be up to 20 dB above
the limits given in Table 2, if duty cycling is being used. The allowed additional emission, or correction
factor, is calculated based on maximum transmission time during 100 ms. Equation 1 can be used to
calculate the correction factor, where t is equal to maximum transmission time during 100 ms.
From Equation 1, it can be calculated that a maximum transmission time of 50 ms, during 100 ms, will
permit all radiation above 1 GHz to be 6 dB above the given limits. For more comparisons, see Table 3.
CF
§
·
t
20 x log ¨
¸
ms
100
©
¹
(1)
Even when an averaging detector is utilised, there is still a limit on emissions measured using a peak
detector function with a limit 20 dB above the average limit.
Table 3. FCC Correction Factor and Maximum Duty Cycling
Measured violating harmonic (using maximum output
power)
-21.23
-25
-30
-35
-40
-41.23
dBm
Regulatory requirement (2nd/3rd harmonics)
-41.23
-41.23
-41.23
-41.23
-41.23
-41.23
dBm
TX ON TIME (ms)
10.00
15.43
27.45
48.81
86.80
100.00
ms
Duty cycle
10.00
15.43
27.45
48.81
86.80
100.00
%
3.1.6
Radiated Emissions
These measurements have to be performed on the final application board to be compliant to the ETSI and
FCC regulations so these measurements are just for pre-qualification purposes.
The reference design board is 4-layer, 1.6 mm thick, FR4 PCB. The radiated emission level will be
dependent on the ground plane, decoupling capacitors and power routing. The choice of antenna will also
affect the radiated emissions.
A dual-band antenna from the CC-Antenna-DK2 was used for the tests. The antenna from the CCAntenna-DK2 was nr 9 and this is widely used on the LaunchPad designs as well; results from the
emission tests are shown in Figure 24 and Figure 25.
It is important that the antenna is matched (VSWR < 3:1) for both sub-1 GHz and 2.4 GHz frequencies.
Otherwise, if the antenna mismatch is large then there will be unwanted emissions and the wanted output
power will be reduced.
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IPC Measurement Results
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Figure 24. Murata - 868 MHz ETSI EN300 220 Radiated Emissions at Max Output Power
Figure 25. JTI - 868 MHz ETSI EN300 220 Radiated Emissions at Max Output Power
3.2
3.2.1
2.4 GHz
CC1352R Output Power, 1 Mbps BLE Sensitivity and Link Budget
Figure 26 shows the output power measurements across a frequency span from 2402-2480 MHz.
Summary: Murata has a higher output power than Johanson with maximum power settings (boost setting).
6
Output Power (dBm)
5.5
5
4.5
4
3.5
3
2400
2410
2420
2430 2440 2450
Frequency (MHz)
2460
2470
2480
D026
Figure 26. 2.4 GHz Output Power v Frequency
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IPC Measurement Results
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Figure 27 shows the sensitivity measurements (1 Mbps BLE data rate) across a frequency span from
2402-2480 MHz.
Summary: Murata has better sensitivity than Johanson.
-96.2
-96.3
Sensitivity (dBm)
-96.4
-96.5
-96.6
-96.7
-96.8
-96.9
-97
2400
Johanson
Murata
2410
2420
2430 2440 2450
Frequency (MHz)
2460
2470
2480
D027
Figure 27. 2.4 GHz 1 Mbps BLE Sensitivity v Frequency
Figure 28 shows the 1 Mbps BLE link budget which is the sum of the output power and the sensitivity
measurements. This is a main parameter for greater range.
Summary: Murata has a greater link budget with maximum output power setting.
103
102.5
Link Budget (dB)
102
101.5
101
100.5
100
99.5
99
2400
2410
2420
2430 2440 2450
Frequency (MHz)
2460
2470
2480
D028
Figure 28. 2.4 GHz 1 Mbps BLE Link Budget v Frequency
3.2.2
CC1352R Tx Efficiency, Tx Harmonics at Maximum Output Power (Boost)
3
•
•
•
•
•
•
•
•
•
•
3.3
V, Maximum output power setting; average results from 2402-2480 MHz:
JTI Tx Efficiency: 4.0 %
Murata Tx Efficiency: 6.0 %
JTI Tx Current: 20.3 mA
Murata Tx Current: 21.1 mA
JTI Tx Output Power: 11.8 dBm
Murata Output Power: 13.9 dBm
JTI 2nd Harmonic Level: -53 dBm
Murata 2nd Harmonic Level: -62 dBm
JTI 3rd Harmonic Level: -60 dBm
Murata 3rd Harmonic Level: -60 dBm
Isolation Between Sub-1 GHz Port and 2.4 GHz Port
These tests were performed to determine if a diplexer or a switch could be used to combine the RF ports
to a common RF port. The tests were conducted on CC1352R EM Rev 1.0 that had a SMA on each RF
port after the IPC.
It is important to note the level of the third harmonic of the 868 MHz on the 2.4 GHz port. The 3rd
harmonic of 868 MHz is 2604 MHz, which is close in frequency to the 2.4 GHz pass band, 2402-2480
MHz.
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Summary
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Maximum output power was transmitted at 868 MHz on the sub-1 GHz port and the level of the third
harmonic was measured on the 2.4 GHz port.
• Discrete reference design: -45 dBm
• Murata IPC: -33 dBm
• Johanson IPC: -33 dBm
It is possible to use a diplexer or switch on the discrete reference design since the isolation between the
two RF ports is sufficient. However, for the IPC solution the isolation is not sufficient to use a diplexer at
868 MHz and 2.4 GHz.
Therefore, a switch is recommended to be used in combination with the IPC to avoid a spurious emission
at 2604 MHz. With an efficient 2.4 GHz antenna directly connected to the IPC 2.4 GHz port or connected
through a diplexer will fail the regulatory limits of ETSI. An additional advantage with the switch is there is
a natural switch isolation which will help to reduce any unwanted harmonics caused through the lower
isolation between the two RF ports.
4
Summary
As an alternative to the discrete reference designs shown in Figure 2, the IPC component reference
design has similar performance of the discrete multi-layer inductor reference design with a lower
component count. 23 passives are required at the CC1352R RF ports. With the IPC, the component count
is reduced from 23 to 3 components, which saves space and reduces pick-and-place assembly costs.
It is recommended to combine the two RF ports into one with a SPDT switch. It is possible to use a
diplexer or switch on the discrete reference design since the isolation between the two RF ports is
sufficient. However, for the IPC solution, the isolation is not sufficient to use a diplexer at 868 MHz and 2.4
GHz.
Table 4 summarizes the link budget for the various reference designs with CC1352R and CC1352P (PA
Tx + Rx configuration) with maximum output power. The values shown in Table 4 will naturally vary with
approximately ± 1 dB at room temperature.
Table 4. Summary of Link Budget at Maximum Output Power
Johanson
Murata
Discrete
CC1352R IPC
868 MHz, 50 kbps
121.6
121.9
123.0
Tx + Rx
915 MHz, 50 kbps
122.1
120.4
123.0
2402-2480 MHz, 1 Mbps
100.3
102.6
101.8
CC1352P IPC
868 MHz
129.2
127.7
129.0
sep Tx PA + Rx
915 MHz
128.8
126.1
129.0
2402-2480 MHz, 1 Mbps
115.9
116.4
116.5
Murata IPC is optimized for maximum output power (boost mode) and Johanson is optimized at the lower
output power steps (normal mode). Tx current is higher for Murata IPC but also has a higher Tx efficiency
at the maximum output power. Johanson IPC has a higher Tx efficiency at the lower output power steps.
Rx current, Isolation and Tx harmonics are similar for both devices.
Johanson IPC is optimized for sub-1 GHz sensitivity, which makes it ideal when using the CC1352P PA as
a pure Tx port and the standard sub-1 GHz port as a pure Rx. For low power sub-1 GHz operations, then
Johanson IPC is ideal. Murata IPC has better link budget performance at 2.4 GHz than Johanson.
Pending on the choice of chip between CC1352R and CC1352P, ISM frequency and output power setting;
both Murata and Johanson have their own particular advantages. It is recommended to evaluate both
vendors since they are drop-in replacements of each other and can be fully evaluated for each application
case.
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21
References
5
www.ti.com
References
1. CC1352R SimpleLink™ High-Performance Dual-Band Wireless MCU Data Sheet
2. CC1352P SimpleLink™ High-Performance Dual-Band Wireless MCU With Integrated Power Amplifier
Data Sheet
3. CC1352R LaunchPad Design Files
4. Johanson Technology Datasheets and Contact Information
5. Murata Contact Information
6. CC1352 IPC Reference Design Files
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Revision History
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Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Original (October 2018) to A Revision .................................................................................................... Page
•
Figure 4 was updated in Section 2.2.2.
................................................................................................
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