Texas Instruments | AN096 Using CC1190 Front End with CC1101 under FCC 15.247 (Rev. A) | Application notes | Texas Instruments AN096 Using CC1190 Front End with CC1101 under FCC 15.247 (Rev. A) Application notes

Texas Instruments AN096 Using CC1190 Front End with CC1101 under FCC 15.247 (Rev. A) Application notes
Application Note AN096
Using the CC1190 Front End with CC1101 under FCC 15.247
By Marius Ubostad and Sverre Hellan
Keywords
Range Extender
FCC Section 15.247
External PA
External LNA
CC1101
1
CC430
CC1100
CC1110
CC1111
CC1190
Introduction
The CC1101 is a truly low-cost, highly
integrated and very flexible RF transceiver.
The CC1101 is primarily designed for use
in low-power applications in the 315, 433,
868 and 915 MHz SRD/ISM bands.
The CC1190 is a range extender for 850950 MHz RF transceivers, transmitters,
and System-on-Chip devices from Texas
Instruments. It increases the link budget by
providing a power amplifier (PA) for
increased output power, and a low-noise
amplifier (LNA) with low noise figure for
improved receiver sensitivity in addition to
switches and RF matching for simple
design of high performance wireless
systems.
This application note outlines the expected
performance when using a CC1101CC1190 design under FCC Section 15.247
in the 902-928 MHz frequency band. This
application note assumes the reader is
familiar with CC1101 and FCC 15.247
regulatory limits. The reader is referred to
[1] and [4] for details.
The application note is also applicable for
CC1100, CC1110, CC1111, and CC430
when used with the CC1190 as they use
the same radio as the CC1101.
Page 1 of 23
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Table of Contents
KEYWORDS.............................................................................................................................. 1
1
INTRODUCTION ............................................................................................................. 1
2
ABBREVIATIONS ........................................................................................................... 2
3
ABSOLUTE MAXIMUM RATINGS ................................................................................. 3
4
ELECTRICAL SPECIFICATIONS ................................................................................... 3
4.1
OPERATING CONDITIONS............................................................................................ 3
4.2
CURRENT CONSUMPTION ........................................................................................... 3
4.3
RECEIVE PARAMETERS .............................................................................................. 4
4.3.1
Typical RX Performance vs. Temperature and VDD ........................................................ 5
4.3.2
Received Signal Strength Indicator (RSSI) ..................................................................... 10
4.4
TRANSMIT PARAMETERS .......................................................................................... 12
4.4.1
Typical TX Performance vs. Temperature and VDD ...................................................... 13
4.4.2
Duty Cycling ................................................................................................................... 16
4.4.3
Typical TX Parameters vs. Load Impedance .................................................................. 17
4.5
MEASUREMENT EQUIPMENT ..................................................................................... 19
5
CONTROLLING THE CC1190...................................................................................... 19
6
SMARTRF STUDIO AND SMARTRF04EB / TRXEB ................................................... 20
6.1
SMARTRF STUDIO ................................................................................................... 20
6.2
SMARTRF04EB / TRXEB......................................................................................... 21
7
REFERENCE DESIGN.................................................................................................. 21
7.1
POWER DECOUPLING ............................................................................................... 21
7.2
INPUT/ OUTPUT MATCHING AND FILTERING ............................................................... 21
7.3
BIAS RESISTOR........................................................................................................ 22
7.4
SAW FILTER ........................................................................................................... 22
7.5
PCB LAYOUT CONSIDERATIONS ............................................................................... 22
7.6
SHIELDING ............................................................................................................... 22
8
DISCLAIMER ................................................................................................................ 23
9
REFERENCES .............................................................................................................. 23
10
GENERAL INFORMATION ........................................................................................... 23
10.1
DOCUMENT HISTORY ............................................................................................... 23
2
Abbreviations
EB
EM
FCC
HGM
LNA
LGM
PA
PCB
PER
RF
RSSI
RX
TrxEB
TX
Evaluation Board
Evaluation Module
Federal Communications Commission
High Gain Mode
Low Noise Amplifier
Low Gain Mode
Power Amplifier
Printed Circuit Board
Packet Error Rate
Radio Frequency
Receive Signal Strength Indicator
Receive, Receive Mode
SmartRF Transceiver EB
Transmit, Transmit Mode
Page 2 of 23
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Application Note AN096
3
Absolute Maximum Ratings
The absolute maximum ratings and operating conditions listed in the CC1101 datasheet [1]
and the CC1190 datasheet [2] must be followed at all times. Stress exceeding one or more of
these limiting values may cause permanent damage to any of the devices.
4
Electrical Specifications
Note that the characteristics in Chapter 4 are only valid when using the CC1101-CC1190EM
915 MHz reference design [3] and register settings recommended by the SmartRF Studio
software [5].
4.1
Operating Conditions
Parameter
Min
Max
Unit
Operating Frequency
Operating Supply Voltage
Operating Temperature
850
2.0
-40
950
3.6
+85
MHz
V
°C
Table 4.1. Operating Conditions
4.2
Current Consumption
TC = 25°C, VDD = 3.0 V, f = 915 MHz if nothing else is stated. All parameters are measured
on the CC1101-CC1190EM 915 MHz reference design [3] with a 50 load.
Parameter
Condition
Receive Current, HGM
Receive Current, LGM
Transmit Current
1
Typical
Unit
1.2 kbps
20
mA
50 kbps
21
mA
250 kbps
22
mA
1.2 kbps
18
mA
50 kbps
19
mA
250 kbps
20
mA
PATABLE = 0x80 (+26 dBm)
PATABLE = 0x8B (+25 dBm)
PATABLE = 0x8E (+24 dBm)
PATABLE = 0x51 (+23 dBm)
PATABLE = 0x3F (+22 dBm)
PATABLE = 0x55 (+21 dBm)
PATABLE = 0x39 (+20 dBm)
PATABLE = 0x2B (+19 dBm)
PATABLE = 0x2A (+18 dBm)
PATABLE = 0x28 (+17 dBm)
PATABLE = 0x35 (+16 dBm)
PATABLE = 0x26 (+15 dBm)
348
305
273
243
228
198
187
166
156
135
131
115
mA
250
nA
Power Down Current
Table 4.2. Current Consumption
1
The RF output power of the CC1101–CC1190 is controlled by the 8 bit value in the CC1101
PATABLE register. The power settings are a small subset of all the possible PATABLE
register settings.
Page 3 of 23
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Application Note AN096
4.3
Receive Parameters
TC = 25°C, VDD = 3.0 V, f = 915 MHz if nothing else is stated. All parameters are measured
on the CC1101-CC1190EM 915 MHz reference design [3] with a 50 load.
Parameter
2
Condition
Typical
Unit
1.2 kbps, GFSK, ±14.3 kHz deviation, 58 kHz RX filter
bandwidth. See Figure 4.1.
-119.5
dBm
4.8 kbps, GFSK, ±25.4 kHz deviation, 58 kHz RX filter
bandwidth.
-114.5
dBm
9.6 kbps, 2FSK, ±4.8 kHz deviation, 58 kHz RX filter
bandwidth.
-112.0
dBm
38.4 kbps, GFSK, ±19.8 kHz deviation, 102 kHz RX filter
bandwidth.
-109.0
dBm
50 kbps, 2FSK, ±25.4 kHz deviation, 135 kHz RX filter
bandwidth. See Figure 4.2
-108.0
dBm
115.2 kbps, GFSK, ±76.2 kHz deviation, 270 kHz RX filter
bandwidth.
-103.0
dBm
250 kbps, GFSK, ±127 kHz deviation, 540 kHz RX filter
bandwidth. See Figure 4.3.
-101.0
dBm
300 kbps, 2FSK, ±76.2 kHz deviation, 464 kHz RX filter
bandwidth.
-95.0
dBm
1.2 kbps, GFSK, ±14.282 kHz deviation, 58 kHz RX filter
bandwidth. See Figure 4.4
-108.0
dBm
50 kbps, 2FSK, ±25.39 kHz deviation, 135 kHz RX filter
bandwidth. See Figure 4.5
-95.0
dBm
250 kbps, GFSK, ±127 kHz deviation, 540 kHz RX filter
bandwidth. See Figure 4.6
-88.0
dBm
Sensitivity , HGM
2
Sensitivity , LGM
Saturation, HGM
Maximum input power level for 1% PER
-28
dBm
Saturation, LGM
Maximum input power level for 1% PER
-11
dBm
1.2 kbps. 58 kHz RX filter bandwidth
Wanted signal 3 dB above the sensitivity level.
Unmodulated interferer. See Figure 4.7.
±2 MHz from wanted signal
±10 MHz from wanted signal
62
72
dB
50 kbps. 102 kHz RX filter bandwidth.
Wanted signal 3 dB above the sensitivity level.
Unmodulated interferer. See Figure 4.8.
±2 MHz from wanted signal
±10 MHz from wanted signal
49
59
dB
250 kbps. 540 kHz RX filter bandwidth.
Wanted signal 3 dB above the sensitivity level.
Unmodulated interferer. See Figure 4.9.
±2 MHz from wanted signal
±10 MHz from wanted signal
40
51
dB
< -60
< -50
dBm
Selectivity and
Blocking,
HGM
Spurious
emission, HGM
Conducted measurement below 1 GHz
Conducted measurement above 1 GHz
Table 4.3. Receive Parameters
2
Sensitivity limit is defined as 1% packet error rate (PER). Packet length is 20 bytes.
Page 4 of 23
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Application Note AN096
4.3.1
Typical RX Performance vs. Temperature and VDD
TC = 25°C, VDD = 3.0 V, f = 915 MHz if nothing else is stated. All parameters are measured
on the CC1101-CC1190EM 915 MHz reference design [3] with a 50 load.
-116
1.2 kbps, 14.282 kHz
1.2 kbps, 14.282 kHz
1.2 kbps, 14.282 kHz
1.2 kbps, 14.282 kHz
Sensitivity (dBm)
-117
dev, 3.6V
dev, 3.3
dev, 3V
dev, 2V
-118
-119
-120
-121
-122
-40
-20
0
20
40
60
80
Temperature ( C)
Figure 4.1. Typical Sensitivity vs. Temperature and Power Supply Voltage, HGM, 1.2 kbps
-104
50 kbps, 25.39 kHz
50 kbps, 25.39 kHz
50 kbps, 25.39 kHz
50 kbps, 25.39 kHz
Sensitivity (dBm)
-105
dev, 3.6V
dev, 3.3
dev, 3V
dev, 2V
-106
-107
-108
-109
-110
-40
-20
0
20
40
60
80
Temperature ( C)
Figure 4.2. Typical Sensitivity vs. Temperature and Power Supply Voltage, HGM, 50 kbps
Page 5 of 23
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Application Note AN096
-96
250 kbps, 127 kHz
250 kbps, 127 kHz
250 kbps, 127 kHz
250 kbps, 127 kHz
-97
Sensitivity (dBm)
-98
dev, 3.6V
dev, 3.3
dev, 3V
dev, 2V
-99
-100
-101
-102
-103
-104
-40
-20
0
20
40
60
80
Temperature ( C)
Figure 4.3. Typical Sensitivity vs. Temperature and Power Supply Voltage, HGM, 250
kbps
-104
1.2 kbps, 14.282 kHz dev, 3.6V
1.2 kbps, 14.282 kHz dev, 3V
1.2 kbps, 14.282 kHz dev, 2V
Sensitivity (dBm)
-105
-106
-107
-108
-109
-110
-40
-20
0
20
40
60
80
Temperature ( C)
Figure 4.4. Typical Sensitivity vs. Temperature and Power Supply Voltage, LGM, 1.2 kbps
Page 6 of 23
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Application Note AN096
-90
50 kbps, 25.39 kHz dev, 3.6V
50 kbps, 25.39 kHz dev, 3V
50 kbps, 25.39 kHz dev, 2V
-91
Sensitivity (dBm)
-92
-93
-94
-95
-96
-97
-98
-40
-20
0
20
40
60
80
Temperature ( C)
Figure 4.5. Typical Sensitivity vs. Temperature and Power Supply Voltage, LGM, 50 kbps
-82
250 kbps, 127 kHz dev, 3.6V
250 kbps, 127 kHz dev, 3V
250 kbps, 127 kHz dev, 2V
Sensitivity (dBm)
-84
-86
-88
-90
-92
-40
-20
0
20
40
60
80
Temperature ( C)
Figure 4.6. Typical Sensitivity vs. Temperature and Power Supply Voltage, LGM, 250 kbps
Page 7 of 23
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Application Note AN096
100
90
Selectivity/Blocking (dB)
80
70
60
50
40
30
20
10
0
-10
-20
-50
1.2kbps, 3dB
-40
-30
-20
-10
0
10
Frequency Offset (MHz)
20
30
40
50
-0.4
-0.2
0
0.2
Frequency Offset (MHz)
0.4
0.6
0.8
1
60
Selectivity/Blocking (dB)
50
40
30
20
10
0
1.2kbps, 3dB
-10
-1
-0.8
-0.6
Figure 4.7. Typical Blocking / Selectivity, 1.2 kbps
Page 8 of 23
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Application Note AN096
100
90
Selectivity/Blocking (dB)
80
70
60
50
40
30
20
10
0
-10
-20
-50
50kbps, 3dB
-40
-30
-20
-10
0
10
Frequency Offset (MHz)
20
30
40
50
-0.4
-0.2
0
0.2
Frequency Offset (MHz)
0.4
0.6
0.8
1
50
Selectivity/Blocking (dB)
40
30
20
10
0
50kbps, 3dB
-10
-1
-0.8
-0.6
Figure 4.8. Typical Blocking / Selectivity, 50 kbps
Page 9 of 23
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Application Note AN096
90
80
Selectivity/Blocking (dB)
70
60
50
40
30
20
10
0
-10
-20
-50
250kbps, 3dB
-40
-30
-20
-10
0
10
Frequency Offset (MHz)
20
30
40
50
-0.4
-0.2
0
0.2
Frequency Offset (MHz)
0.4
0.6
0.8
1
40
Selectivity/Blocking (dB)
30
20
10
0
-10
250kbps, 3dB
-20
-1
-0.8
-0.6
Figure 4.9: Typical Blocking / Selectivity, 250 kbps
4.3.2
Received Signal Strength Indicator (RSSI)
The CC1101-CC1190 RSSI readouts can be converted to an absolute level in dBm by
subtracting an offset. A CC1101-CC1190 design has a different offset value compared to a
standalone CC1101 design due to the CC1190 external LNA gain and the SAW filter insertion
loss. Table 4.4 gives the typical offset value for HGM and LGM. Refer to the CC1101 data
sheet [1] for more details on how to convert the RSSI readout to an absolute power level in
dBm.
HGM
81
LGM
63
Table 4.4. Typical RSSI Offset Values
Page 10 of 23
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Application Note AN096
-20
-30
RSSI Reading (dBm)
-40
-50
-60
-70
-80
-90
-100
-110
-120
-120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10
Input Power (dBm)
0
Figure 4.10. Typical RSSI vs. Input Power Level, HGM, 50 kbps
0
-10
RSSI Reading (dBm)
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10
Input Power (dBm)
0
Figure 4.11. Typical RSSI vs. Input Power Level, LGM, 50 kbps
Page 11 of 23
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Application Note AN096
4.4
Transmit Parameters
TC = 25°C, VDD = 3.0 V, f = 915 MHz if nothing else is stated. All parameters are measured
on the CC1101-CC1190EM 915 MHz reference design [3] with a 50
load, except for the
load-pull measurements. Radiated measurements are done with the kit antenna.
Parameter
Condition
Output power , HGM
PATABLE = 0x80
PATABLE = 0x8B
PATABLE = 0x8E
PATABLE = 0x51
PATABLE = 0x3F
PATABLE = 0x55
PATABLE = 0x39
PATABLE = 0x2B
PATABLE = 0x2A
PATABLE = 0x28
PATABLE = 0x35
PATABLE = 0x26
26
25
24
23
22
21
20
19
18
17
16
15
dBm
Efficiency, HGM
PATABLE = 0x80
PATABLE = 0x8B
PATABLE = 0x8E
PATABLE = 0x51
PATABLE = 0x3F
PATABLE = 0x55
37
34
31
27
24
21
%
1
Spurious emission
with PATABLE = 0x80, HGM
Typical
Conducted below 1 GHz
nd
Conducted 2 harmonic
nd
Conducted except 2 harmonic
< -60
< -9
< -49
Radiated above 2
nd
harmonic
< -38
Spurious emission
with PATABLE = 0x8E, HGM
Radiated above 2
nd
harmonic
< -41.2
20 dB bandwidth, HGM
1.2 kbps, GFSK, ±14.3 kHz deviation
4.8 kbps, GFSK, ±25.4 kHz deviation
9.6 kbps, 2FSK, ±4.8 kHz deviation
38.4 kbps, GFSK, ±19.8 kHz deviation
50 kbps, 2FSK, ±25.4 kHz deviation
115.2 kbps, GFSK, ±76.2 kHz deviation
250 kbps, GFSK, ±127 kHz deviation
Stability, HGM
Maximum VSWR
with PATABLE = 0x80
26.3
67.0
28.6
79.7
116.4
201.2
430.3
+25˚C - +85˚C:
VDD: 2.0 – 3.6 V
<6
-20˚C:
VDD: 2.0 – 3.6 V
VDD: 2.0 – 3.0 V
<3
< 4.5
-40˚C:
VDD: 2.0 – 3.6 V
VDD: 2.0 – 3.0 V
<3
< 4.5
Unit
dBm
dBm
kHz
Table 4.5. Transmit Parameters
Page 12 of 23
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Application Note AN096
4.4.1
Typical TX Performance vs. Temperature and VDD
TC = 25°C, VDD = 3.0 V, f = 915 MHz if nothing else is stated. All parameters are measured
on the CC1101-CC1190EM 915 MHz reference design [3] with a 50 load.
28
Output Power (dBm)
27
26
0x80, 3.6V
0x80, 3.3V
0x80, 3V
0x80, 2V
25
24
23
22
21
20
-40
-20
0
20
40
Temperature ( C)
60
80
Figure 4.12. Typical Output Power vs. Temperature and Power Supply Voltage. PATABLE
= 0x80
28
0x8E, 3.6V
0x8E, 3.3V
0x8E, 3V
0x8E, 2V
Output Power (dBm)
27
26
25
24
23
22
21
20
-40
-20
0
20
40
Temperature ( C)
60
80
Figure 4.13. Typical Output Power vs. Temperature and Power Supply Voltage. PATABLE
= 0x8E
Page 13 of 23
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Application Note AN096
Transmit Current (mA)
450
0x80, 3.6V
0x80, 3.3V
0x80, 3V
0x80, 2V
400
350
300
250
200
-40
-20
0
20
40
Temperature ( C)
60
80
Figure 4.14. Typical TX Current Consumption vs. Temperature and Power Supply Voltage.
PATABLE = 0x80
340
0x8E, 3.6V
0x8E, 3.3V
0x8E, 3V
0x8E, 2V
Transmit Current (mA)
320
300
280
260
240
220
200
180
-40
-20
0
20
40
Temperature ( C)
60
80
Figure 4.15. Typical TX Current Consumption vs. Temperature and Power Supply Voltage.
PATABLE = 0x8E
Page 14 of 23
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Figure 4.16. Typical Modulation Bandwidth, 50 kbps, PATABLE = 0x80. Measured
according to FCC 15.247
Page 15 of 23
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Application Note AN096
4.4.2
Duty Cycling
Section 15.209 gives the general limits for the emission of intentional or unintentional
radiators. Above 960 MHz the limit is -41.2 dBm (500 uV/m at 3 m distance). When operating
under Section 15.247 the spurious emission must be 20 dB below the carrier unless it falls
within one of the restricted bands defined in Section 15.205. When operating in the in the 902rd
th
th
th
928 MHz frequency range the 3 , 4 , 5 , and 6 harmonics fall within restricted bands. In the
restricted bands the general limits of -41.2 dBm apply.
Pulsed transmissions allow higher peak harmonic and spurious emissions above 1 GHz
because an averaging detector is called for in the measurements. The average limit must be
below -41.2 dBm, but maximum peak spurious level for pulsed transmission is 20 dB above
the average limit. If the duty cycle factor of the periodic signal is known, measuring the peak
value and adding a duty cycle relaxation factor determines the average value. The relaxation
factor applies to the TX on-time as measured over a 100 ms period. The relaxation factor is
20 log (TX on-time/100 ms) [dB].
As an example, a 50 % duty cycle allows for 6 dB higher peak emission than without duty
cycling. Figure 4.17 gives the relaxation factor for different transmission on-times over a 100
ms period.
If the TX on-time is above 100 ms duty cycle relaxation cannot be applied and the maximum
output power, when using the CC1101+CC1190 915 MHz reference design, is limited to +24
dBm (see Table 4.5).
The CC1101+CC1190 915 MHz reference design has a maximum output power of +26 dBm.
rd
The radiated 3 harmonic is then typically <-38 dBm and a minimum 3.2 dB duty cycle
relaxation factor must be applied to get the average value below -41.2 dBm. The maximum
TX on-time in any 100 ms period is thus limited to 69 ms as seen in Figure 4.17.
10
Relaxation Factor (dB)
9
8
7
6
5
4
3
2
1
0
30
40
50
60
70
On-time (ms)
80
90
100
Figure 4.17. Relaxation Factor vs. Duty Cycling
Page 16 of 23
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Application Note AN096
4.4.3
Typical TX Parameters vs. Load Impedance
The load impedance presented to the CC1190 PA output is critical to the TX performance of
the reference design. The load impedance is selected as a compromise between several
criteria, such as output power, efficiency and the level of the harmonics. The matching
components between the PA output and the antenna should transform 50 ohm antenna
impedance to the selected impedance which the CC1190 PA should see. This is taken care of
by the reference design and the user should provide a well matched antenna to get the
required performance.
In order to measure the performance under different mismatch conditions the CC1101CC1190EM 915 MHz reference design is loaded with different impedances at the SMA
connector reference plane. A well matched antenna will have impedance inside the black
circle in the Smith chart, which illustrates the limit for 10 dB return loss. At each load the
output power, current and spurious frequency components are measured. These
measurements are known as load-pull measurements.
Current (mA)
Output power (dBm)
550
26
Temp = 25 C
Vdd = 3 V
25
Temp = 25 C
Vdd = 3 V
500
24
450
23
400
22
350
21
20
300
19
250
18
200
17
VSWR: 1.93
Return Loss: 10 dB
VSWR: 1.93
Return Loss: 10 dB
150
Figure 4.18. Output Power (left) and Current (right) vs. Load Impedance at SMA
Connector at 25°C. PATABLE = 0x80.
Most PAs have the ability to oscillate at unwanted frequencies under certain conditions. The
worst conditions are usually high output power, low temperatures, and high VDD. This is also
the case for CC1190. The spurious frequency components are measured under different
mismatch conditions as illustrated in Figure 4.19 and Figure 4.20. The blue colors indicate that
the spurious levels are at the noise floor. The CC1101-CC1190EM 915 MHz reference design
is a very robust design which tolerates high mismatch ratios at high output power, low
temperatures and high VDD.
Page 17 of 23
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Application Note AN096
Spur DC to fundamental (dBm)
Spur DC to fundamental (dBm)
0
-10
Temp = 25 C
Vdd = 3.6 V
Temp = 25 C
Vdd = 3 V
-5
-15
-10
-20
-15
-25
-20
-25
-30
-30
-35
-35
-40
-40
-45
-45
VSWR: 6
Return Loss: 2.9 dB
VSWR: 10
Return Loss: 1.7 dB
Figure 4.19. Spurious Frequency Components vs. Load Impedance at SMA Connector at
25°C. PATABLE = 0x80.
Spur DC to fundamental (dBm)
Spur DC to fundamental (dBm)
5
Temp = -40 C
Vdd = 3 V
0
10
Temp = -40 C
Vdd = 3.6 V
5
0
-5
-5
-10
-10
-15
-15
-20
-20
-25
-25
-30
-30
-35
-35
-40
-40
-45
-45
VSWR: 3
Return Loss: 6 dB
VSWR: 4.5
Return Loss: 3.9 dB
Figure 4.20. Spurious Frequency Components vs. Load Impedance at SMA Connector at
-40°C. PATABLE = 0x80.
Page 18 of 23
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Application Note AN096
4.5
Measurement Equipment
The following equipment was used for the measurements.
Measurement
Instrument Type
RX
Signal Generator
TX
Signal Analyzer
Power Supply
Multimeter
Automatic Tuner
EMC chamber
RX/TX
Stability
Radiated spurious Emissions
Instrument Model
Rohde & Schwarz SMF
Rohde & Schwarz SMIQ 06B
Rohde & Schwarz FSG
Agilent E3631A
Keithley 2000
Maury MT986EU32
Table 4.6. Measurement Equipment
5
Controlling the CC1190
There are three digital control pins (PA_EN, LNA_EN, and HGM) that sets the CC1190 mode
of operation.
PA_EN
0
0
0
1
1
LNA_EN
0
1
1
0
0
HGM
X
0
1
0
1
Mode of Operation
Power Down
RX LGM
RX HGM
TX LGM
TX HGM
Table 5.1. CC1190 Control Logic
There are different ways of controlling the CC1190 mode of operation in a CC1101-CC1190
design.
3
Using CC1101 GDO0 and GDO2 pins to set two of the CC1190 control signals (e.g.
PA_EN and LNA_EN). The third control signal (e.g. HGM) can be hardwired to
GND/VDD or connected to an external MCU.
Using an external MCU to control PA_EN, LNA_EN, and HGM.
Using an external MCU to set two (or all three) digital control signals is the recommended
solution for a CC1101-CC1190 design since GDO0 or GDO2 is typically programmed to
provide a signal related to the CC1101 packet handler engine to the interfacing MCU and
GDO1 is the same pin as the SO pin on the SPI interface. The GDO pin not used to provide
information to the interfacing MCU can be used to control the CC1190.
Figure 5.1 shows a simplified application circuit where an external MCU controls HGM and
LNA_EN. PA_EN is controlled either by external MCU or one of the CC1101 GDO pins.
3
GDO1 is not used since this is the same pin as the SO pin on the SPI interface. The output
programmed on this pin will only be valid when CSn is high.
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Application Note AN096
VDD
VDD_LNA
VDD_PA1
PA_OUT
VDD_PA2
VDD
PA_IN
RF_P
SAW
RF_N
LNA_OUT
CC110x/CC111x
CC1190
TR_SW
GDOx
PA_EN
LNA_EN
BIAS
LNA_IN
HGM
Connected to MCU
Connected to
VDD/GND/MCU
Figure 5.1. Simplified CC11xx-CC1190 Application Circuit
6
SmartRF Studio and SmartRF04EB / TrxEB
The CC1101-CC1190EM 915 MHz together with SmartRF™ Studio 7 software [5] and
SmartRF04EB or TrxEB can be used to evaluate performance and functionality.
6.1
SmartRF Studio
The CC1101-CC1190 can be configured using the SmartRF Studio 7 software [5]. The
SmartRF Studio software is highly recommended for obtaining optimum register settings.
SmartRF Studio 7 uses an external MCU (the USB controller on the Evaluation Boards) to
control the three digital control pins (PA_EN, LNA_EN, and HGM). A screenshot of the
SmartRF Studio user interface for CC1101-CC1190 is shown in Figure 6.1.
Figure 6.1. SmartRF Studio 7 [5] User Interface (868 MHz version shown)
In order to control the CC1190 the user needs to select CC1190 as “Range Extender” and
select the appropriate “EM Revisions” as shown in Figure 6.1.
Page 20 of 23
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Application Note AN096
6.2
SmartRF04EB / TRxEB
If the SmartRF04EB is connected to a USB socket on a PC, it will draw power from the USB
bus when the switch is in the position shown in Figure 6.2. The onboard voltage regulator
supplies 3.3 V to the board, but has limited current source capability and cannot supply the
CC1101-CC1190EM. An external supply is therefore needed and shall be connected as
shown in Figure 6.2, where the red wire is the positive supply and the black wire is GND. With
the test setup in Figure 6.2 the SmartRF04EB is connected to a 3.3 V supply through the USB
and voltage regulator and CC1101-CC1190 is powered by the external supply. Since the
SmartRF04EB is connected to a regulated 3.3 V supply the signals going from CC1101CC1190 to SmartRF04EB (and vice versa) need to be within 3.0 V to 3.6 V. The external
supply connected to CC1101-CC1190 when using the test setup in Figure 6.2 is therefore
limited to 3.0 V to 3.6 V.
Figure 6.2. SmartRF04EB Connection
If CC1101-CC1190 is used with the TrxEB and the USB controller the supply range is 3.0 V to
3.6 V.
7
Reference Design
The CC1101-CC1190EM 915 MHz reference design includes schematic and gerber files [3]. It
is highly recommended to follow the reference design for optimum performance. The
reference design also includes bill of materials with manufacturers and part numbers.
7.1
Power Decoupling
Proper power supply decoupling must be used for optimum performance. The capacitors C27C29 ensure good RF ground after L21 and thus prevent RF leakage into the power supply
lines causing oscillations. The power supply filtering consisting of C2, C3 and L2 ensure well
defined impedance looking towards the power supply.
7.2
Input/ Output Matching and Filtering
The PA and the LNA of the CC1190 are single ended input/output. A balun is required to
transform the differential output of the CC1101 to single ended input of the CC1190 PA and
the single ended output of the LNA to the differential input of CC1101. The values of the
matching components between the SAW filter and the CC1190 PA input are chosen to
present optimum source impedance to the CC1190 PA input with respect to stability.
The CC1190 PA performance is highly dependent on the impedance presented at the output,
and the LNA performance is highly dependent on the impedance presented at the input. The
impedance is defined by L21 and all components towards the antenna. These components
also ensure the required filtering of harmonics to pass regulatory requirements.
The layout and component values need to be copied exactly to obtain the same performance
as presented in this application note.
Page 21 of 23
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Application Note AN096
7.3
Bias Resistor
R141 is a bias resistor. The bias resistor is used to set an accurate bias current for internal
use in the CC1190.
7.4
SAW Filter
A SAW is recommended for the CC1101-CC1190 design to attenuate spurs below the carrier
frequency that will otherwise violate spurious emission limits under Section 15.209 and 15.205
The SAW filter is matched to the CC1190 PA input/LNA output impedance using a series
inductor and a shunt capacitor.
7.5
PCB Layout Considerations
The Texas Instruments reference design uses a 1.6 mm (0.062”) 4-layer PCB solution. Note
that the different layers have different thickness. It is recommended to follow the
recommendation given in the CC1101–CC1190EM 915 MHz reference design [3] to ensure
optimum performance.
The top layer is used for components and signal routing, and the open areas are filled with
metallization connected to ground using several vias. The areas under the two chips are used
for grounding and must be well connected to the ground plane with multiple vias. Footprint
recommendation for the CC1190 is given in the CC1190 datasheet [2].
Layer two is a complete ground plane and is not used for any routing. This is done to ensure
short return current paths. The low impedance of the ground plane prevents any unwanted
signal coupling between any of the nodes that are decoupled to it.
Layer three is a power plane. The power plane ensures low impedance traces at radio
frequencies and prevents unwanted radiation from power traces.
Layer four is used for routing, and as for layer one, open areas are filled with metallization
connected to ground using several vias.
7.6
Shielding
RF shielding is necessary to keep the radiated harmonics below the regulatory limits.
Page 22 of 23
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Application Note AN096
8
Disclaimer
The CC1101-CC1190EM evaluation board is intended for use for ENGINEERING
DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES ONLY and is not
considered by TI to be a finished end-product fit for general consumer use. Persons handling
the product(s) must have electronics training and observe good engineering practice
standards. As such, the goods being provided are not intended to be complete in terms of
required design-, marketing-, and/or manufacturing-related protective considerations,
including product safety and environmental measures typically found in end products that
incorporate such semiconductor components or circuit boards. This evaluation board has
been tested against FCC Section 15.247, 15.209, and 15.205 regulations, but there has been
no formal compliance testing at an external test house. It is the end user's responsibility to
ensure that his system complies with applicable regulations.
9
References
[1]
CC1101 Datasheet (SWRS061.pdf)
[2]
CC1190 Datasheet (SWRS089.pdf)
[3]
CC1101–CC1190EM 915 MHz Reference Design (SWRR077.zip)
[4]
FCC rules (www.fcc.gov)
[5]
SmartRF Studio 7 (SWRC176.zip)
™
10 General Information
10.1 Document History
Revision
SWRA361
SWRA361A
Date
2011.03.28
2011.05.02
Description/Changes
Initial release.
Corrected figure text in Figure 4.20 from 25C to -40C
Page 23 of 23
SWRA361A
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