Texas Instruments | AN094 -- Using the CC1190 Front End with CC1101 under EN 300 220 | Application notes | Texas Instruments AN094 -- Using the CC1190 Front End with CC1101 under EN 300 220 Application notes

Texas Instruments AN094 -- Using the CC1190 Front End with CC1101 under EN 300 220 Application notes
Application Note AN094
Using the CC1190 Front End with CC1101 under EN 300 220
By Charlotte Seem, Marius Ubostad and Sverre Hellan
Keywords
•
•
•
•
•
1
•
•
•
•
•
Range Extender
EN 300 220
External PA
External LNA
CC1101
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 EN 300 220-1
V2.3.1 [4] in the 869.4-869.65 MHz
frequency sub-band (g3). The maximum
allowed output power in the 869.4-869.65
MHz sub-band is +27 dBm (500 mW), but
due to the CC1101 phase noise the
maximum output power using the
CC1101-CC1190EM 869 MHz reference
design [3] is approximately +18 dBm in
order to meet modulation bandwidth
requirements. The final output power level
will depend on the antenna being used.
For details on the regulatory limits in the
863-870 MHz SRD frequency bands,
please refer to the ETSI EN 300 220-1
V2.3.1 [4] and ERC Recommendation 7003 [5]. These can be downloaded from
www.etsi.org and www.ero.dk.
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.
This application note assumes the reader
is familiar with CC1101 and EN 300 220.
The reader is referred to [2] and [4] for
details.
Page 1 of 22
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Application Note AN094
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 Curves ......................................................................................5
4.3.2
Received Signal Strength Indicator (RSSI).....................................................................11
4.3.3
Listen Before Talk (LBT) Threshold ...............................................................................12
4.4
TRANSMIT PARAMETERS .......................................................................................... 13
4.4.1
Typical TX Performance Curves ....................................................................................14
5
MEASUREMENT EQUIPMENT.................................................................................... 18
6
CONTROLLING THE CC1190 ..................................................................................... 18
7
CC1101 REGISTER SETTINGS................................................................................... 19
8
SMARTRF STUDIO AND SMARTRF04EB / TRXEB .................................................. 19
8.1
SMARTRF STUDIO ................................................................................................... 19
8.2
SMARTRF04EB / TRXEB ........................................................................................ 20
9
REFERENCE DESIGN ................................................................................................. 21
9.1
POWER DECOUPLING ............................................................................................... 21
9.2
INPUT/ OUTPUT MATCHING AND FILTERING ................................................................ 21
9.3
BIAS RESISTOR ........................................................................................................ 21
9.4
CRYSTAL ................................................................................................................. 21
9.5
SAW FILTER ........................................................................................................... 21
9.6
PCB LAYOUT CONSIDERATIONS ............................................................................... 21
10
DISCLAIMER ................................................................................................................ 22
11
REFERENCES.............................................................................................................. 22
12
GENERAL INFORMATION .......................................................................................... 22
12.1
DOCUMENT HISTORY................................................................................................ 22
2
Abbreviations
AFA
EB
EIRP
EM
HGM
LBT
LNA
LGM
PA
PCB
PER
RF
RSSI
RX
SoC
TrxEB
TX
Adaptive Frequency Agility
Evaluation Board
Equivalent Isotropically Radiated Power
Evaluation Module
High Gain Mode
Listen-before-Talk
Low Noise Amplifier
Low Gain Mode
Power Amplifier
Printed Circuit Board
Packet Error Rate
Radio Frequency
Receive Signal Strength Indicator
Receive, Receive Mode
System-on-Chip
SmartRF Transceiver EB
Transmit, Transmit Mode
Page 2 of 22
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Application Note AN094
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 recommended
register settings presented in Chapter 7 and the CC1101-CC1190EM 869 MHz reference
design [3].
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 = 869.525 MHz if nothing else is stated. All parameters are
measured on the CC1101-CC1190EM 869 MHz reference design [3] with a 50 Ω load.
Parameter
Receive Current, HGM
Receive Current, LGM
Transmit Current1
Condition
Typical
Unit
1.2 kbps
20
mA
4.8 kbps
20
mA
38.4 kbps
20
mA
1.2 kbps
17
mA
4.8 kbps
17
mA
38.4 kbps
17
mA
PATABLE = 0x54 (+20 dBm)
PATABLE = 0x55 (+19 dBm)
PATABLE = 0x57 (+18 dBm)
PATABLE = 0x36 (+17 dBm)
PATABLE = 0x28 (+16 dBm)
PATABLE = 0x27 (+15 dBm)
138
132
120
112
104
99
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 22
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Application Note AN094
4.3
Receive Parameters
TC = 25°C, VDD = 3.0 V, f = 869.525 MHz if nothing else is stated. All parameters are
measured on the CC1101-CC1190EM 869 MHz reference design [3] with a 50 Ω load.
Parameter
Typical
Unit
1.2 kbps, GFSK, ±14.8 kHz deviation, 60 kHz RX filter
bandwidth. See Figure 4.1.
-118
dBm
1.2 kbps, GFSK, ±4.9 kHz deviation, 60 kHz RX filter
bandwidth. See Figure 4.1.
-115
dBm
4.8 kbps, GFSK, ±24.7 kHz deviation, 105 kHz RX filter
bandwidth. See Figure 4.2.
-113
dBm
38.4 kbps, GFSK, ±19.8 kHz deviation, 105 kHz RX filter
bandwidth. See Figure 4.3.
-108
dBm
1.2 kbps, GFSK, ±14.8 kHz deviation, 60 kHz RX filter
bandwidth. See Figure 4.4.
-104
dBm
1.2 kbps, GFSK, ±4.9 kHz deviation, 60 kHz RX filter
bandwidth. See Figure 4.4.
-101
dBm
4.8 kbps, GFSK, ±24.7 kHz deviation, 105 kHz RX filter
bandwidth. See Figure 4.5.
-99
dBm
38.4 kbps, GFSK, ±19.8 kHz deviation, 105 kHz RX filter
bandwidth. See Figure 4.6.
-94
dBm
Saturation, HGM
Maximum input power level for 1% PER
-23
dBm
Saturation, LGM
Maximum input power level for 1% PER
-6
dBm
1.2 kbps. 60 kHz RX filter bandwidth
Wanted signal 3 dB and 16 dB above the sensitivity level.
Unmodulated interferer. See Figure 4.7.
±2 MHz from wanted signal3
±10 MHz from wanted signal4
60
83
dB
4.8 kbps. 105 kHz RX filter bandwidth.
Wanted signal 3 dB and 16 dB above the sensitivity level.
Unmodulated interferer. See Figure 4.8.
±2 MHz from wanted signal
±10 MHz from wanted signal
55
80
dB
38.4 kbps. 105 kHz RX filter bandwidth.
Wanted signal 3 dB and 16 dB above the sensitivity level.
Unmodulated interferer. See Figure 4.9.
±2 MHz from wanted signal
±10 MHz from wanted signal
55
80
dB
2
Sensitivity , HGM
Sensitivity, LGM
Selectivity and
Blocking,
HGM and LGM
Spurious
emission5, HGM
Condition
Conducted measurement below 1 GHz
Conducted measurement above 1 GHz
< -70
< -70
Radiated VCO leakage (See Figure 4.10)
< -54
dBm
Table 4.3. Receive Parameters
2
Sensitivity limit is defined as 1% packet error rate (PER). Packet length is 20 bytes.
Receiver class 2. Limit at ±2 MHz offset: ≥35 dB – 10log(RX_BW/16). RX_BW in kHz.
4
Receiver class 2. Limit at ±10 MHz offset: ≥60 dB – 10log(RX_BW/16). RX_BW in kHz.
5
ETSI EN 300 220 limit: -57 dBm below 1 GHz, -47 dBm above 1 GHz
3
Page 4 of 22
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Application Note AN094
4.3.1
Typical RX Performance Curves
TC = 25°C, VDD = 3.0 V, f = 869.525 MHz if nothing else is stated. All parameters are
measured on the CC1101-CC1190EM 869 MHz reference design [3] with a 50 Ω load.
-111.0
-112.0
Sensitivity [dBm]
-113.0
-114.0
-115.0
-116.0
-117.0
-118.0
-119.0
-120.0
-121.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Temperature [C]
1.2 kbps, 14.3 kHz dev, 2V
1.2 kbps, 14.3 kHz dev, 3V
1.2 kbps, 14.3 kHz dev, 3.6V
1.2 kbps, 4.9 kHz dev, 2V
1.2 kbps, 4.9 kHz dev, 3V
1.2 kbps, 4.9 kHz dev, 3.6V
Figure 4.1. Typical Sensitivity vs. Temperature and Power Supply Voltage, HGM, 1.2 kbps
-109.0
Sensitivity [dBm]
-110.0
-111.0
-112.0
-113.0
-114.0
-115.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Temperature [C]
4.8 kbps, 2V
4.8 kbps, 3V
4.8 kbps, 3.6V
Figure 4.2. Typical Sensitivity2 vs. Temperature and Power Supply Voltage, HGM, 4.8 kbps
Page 5 of 22
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Application Note AN094
-104.0
-105.0
Sensitivity [dBm]
-106.0
-107.0
-108.0
-109.0
-110.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Tem perature [C]
38.4 kbps, 2V
38.4 kbps, 3V
38.4 kbps, 3.6V
Figure 4.3. Typical Sensitivity2 vs. Temperature and Power Supply Voltage, HGM, 38.4 kbps
-96.0
Sensitivity [dBm]
-98.0
-100.0
-102.0
-104.0
-106.0
-108.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Temperature [C]
1.2 kbps, 14.3 kHz dev, 2V
1.2 kbps, 14.3 kHz dev, 3V
1.2 kbps, 14.3 kHz dev, 3.6V
1.2 kbps, 4.9 kHz dev, 2V
1.2 kbps, 4.9 kHz dev, 3V
1.2 kbps, 4.9 kHz dev, 3.6V
Figure 4.4. Typical Sensitivity2 vs. Temperature and Power Supply Voltage, LGM, 1.2 kbps
Page 6 of 22
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Application Note AN094
-94.0
-95.0
Sensitivity [dBm]
-96.0
-97.0
-98.0
-99.0
-100.0
-101.0
-102.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Temperature [C]
4.8 kbps, 2V
4.8 kbps, 3V
4.8 kbps, 3.6V
Figure 4.5. Typical Sensitivity2 vs. Temperature and Power Supply Voltage, LGM, 4.8 kbps
-88.0
-89.0
Sensitivity [dBm]
-90.0
-91.0
-92.0
-93.0
-94.0
-95.0
-96.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Tem perature [C]
38.4 kbps, 2V
38.4 kbps, 3V
38.4 kbps, 3.6V
Figure 4.6. Typical Sensitivity2 vs. Temperature and Power Supply Voltage, LGM, 38.4 kbps
Page 7 of 22
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Application Note AN094
100.0
90.0
80.0
70.0
Blocking/Selectivity [dB]
60.0
50.0
40.0
30.0
|
20.0
10.0
0.0
-55
-45
-35
-25
-15
-5
5
15
25
35
45
55
-10.0
-20.0
Frequency Offset [MHz]
1.2 kbps, 3 dB
70.0
60.0
50.0
Selectivity [dB]
40.0
30.0
20.0
10.0
0.0
-1.5
-1
-0.5
0
0.5
1
1.5
-10.0
Frequency Offset [MHz]
1.2 kbps, 3 dB
1.2 kbps, 16 dB
Figure 4.7. Typical Blocking / Selectivity, 1.2 kbps
Page 8 of 22
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Application Note AN094
100.0
90.0
80.0
70.0
Blocking/Selectivity [dB]
60.0
50.0
40.0
30.0
20.0
10.0
0.0
-55
-45
-35
-25
-15
-5
5
15
25
35
45
55
-10.0
Frequency Offset [MHz]
4.8 kbps, 3 dB
60.0
50.0
40.0
Selectivity [dB]
30.0
20.0
10.0
0.0
-1.5
-1
-0.5
0
0.5
1
1.5
-10.0
Frequency Offset [MHz]
4.8 kbps, 3 dB
4.8 kbps, 16 dB
Figure 4.8. Typical Blocking / Selectivity, 4.8 kbps
Page 9 of 22
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Application Note AN094
100.0
90.0
80.0
70.0
Blocking/Selectivity [dB]
60.0
50.0
40.0
30.0
20.0
10.0
0.0
-55
-45
-35
-25
-15
-5
5
15
25
35
45
55
-10.0
-20.0
Frequency Offset [MHz]
38.4 kbps, 3 dB
60.0
50.0
40.0
Selectivity [dB]
30.0
20.0
10.0
0.0
-1.5
-1
-0.5
0
0.5
1
1.5
-10.0
-20.0
Frequency Offset [MHz]
38.4 kbps, 3 dB
38.4 kbps, 16 dB
Figure 4.9. Typical Blocking / Selectivity, 38.4 kbps
-30
-32
-34
-36
-38
-40
-42
-44
Level in dBm
-46
ETSI EN300 220 EN300 328 EN300 440 RX VCO leakage
-48
-50
-52
-54
-56
-58
-60
-62
-64
-66
-68
-70
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
Frequency in MHz
Figure 4.10. Typical RX Radiated Spurious Emission, HGM (VCO leakage worst angle)
Page 10 of 22
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Application Note AN094
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
-20
-30
-40
-50
RSSI Reading [dBm]
-60
-70
-80
-90
-100
-110
-120
-120
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
Input Power [dBm]
RSSI HGM 38.4 kbps, 3V, +25C
Figure 4.11. Typical RSSI vs. Input Power Level, HGM, 38.4 kbps
0
-10
-20
-30
RSSI Reading [dBm]
-40
-50
-60
-70
-80
-90
-100
-110
-120
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
Input Power [dBm]
RSSI LGM 38.4 kbps, 3V, +25C
Figure 4.12. Typical RSSI vs. Input Power Level, LGM, 38.4 kbps
Page 11 of 22
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Application Note AN094
4.3.3
Listen Before Talk (LBT) Threshold
If LBT is implemented in the protocol the channel is not considered available for use if the
received signal is above the LBT threshold. Conversely, if the received signal is below the
LBT threshold, the channel is considered available for use. Note that if the protocol
implements LBT without Adaptive Frequency Agility (AFA), the duty cycle limit applies. Refer
to EN 300 220-1 V2.3.1 for more details [4].
For a given AGCCTRL2.MAX_LNA_GAIN and AGCCTRL2.MAX_DVGA_GAIN register
setting the absolute threshold can be adjusted ±7 dB in steps of 1 dB using
AGCCTRL1.CARRIER_SENSE_ABS_THR. See CC1101 data sheet [1] for more details.
Table 4.5 shows the LBT threshold for HGM and LGM mode with
CARRIER_SENSE_ABS_THR = 7 (+7 dB) and 9 (-7 dB) respectively. Table 4.5 shows that
CC1101-CC1190EM 869 MHz reference design comply with the EN 300 220-1 V2.3.1 LBT
threshold limit for both HGM and LGM.
If the protocol implements LBT it is better to have the threshold closer to the LBT threshold
limit. It is recommended, but not required to have the CC1190 in LGM when doing LBT.
Data Rate [kbps]
1.2
4.8
38.4
RX BW [kHz]
60
105
105
HGM [dBm]
-98 (+7 dB)
-96 (+7 dB)
-97 (+7 dB)
LGM [dBm]
-93 (-7 dB)
-90 (-7 dB)
-90 (-7 dB)
Limit6 [dBm]
-92.3 / -96.3
-89.8 / -93.8
-89.8 / -93.8
Table 4.5. Typical LBT Threshold (the number in brackets refer to
CARRIER_SENSE_ABS_THR setting used)
6
Limits are for output power <100 mW / 500 mW
Page 12 of 22
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Application Note AN094
4.4
Transmit Parameters
TC = 25°C, VDD = 3.0 V, f = 869.525 MHz if nothing else is stated. All parameters are
measured on the CC1101-CC1190EM 869 MHz reference design [3] with a 50 Ω load.
Radiated measurements are done with the kit antenna.
Parameter
Condition
Output power, HGM
PATABLE = 0x54
PATABLE = 0x55
PATABLE = 0x57
PATABLE = 0x36
PATABLE = 0x28
PATABLE = 0x27
20
19
18
17
16
15
dBm
Efficiency, HGM
PATABLE = 0x54
PATABLE = 0x55
PATABLE = 0x57
PATABLE = 0x36
PATABLE = 0x28
PATABLE = 0x27
22
20
17
14
12
11
%
Spurious emission
with PATABLE = 0x54, HGM
Typical
Conducted below 1 GHz
Conducted above 1 GHz
< -60
< -55
Radiated below 1 GHz
Radiated above 1 GHz
< -60
< -36
Unit
dBm
See Figure 4.17 for radiated measurements
above 1 GHz
Modulation bandwidth, HGM
Stability, HGM
Maximum VSWR
with PATABLE = 0x54
See Figure 4.18
+25˚C - +85˚C:
VDD: 2.0 – 3.6 V
< 15
-20˚C:
VDD: 2.0 – 3.6 V
< 11.5
-40˚C:
VDD: 2.0 – 3.6 V
VDD: 2.0 – 3.4 V
<4
< 5.5
Table 4.6. Transmit Parameters
Page 13 of 22
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Application Note AN094
4.4.1
Typical TX Performance Curves
TC = 25°C, VDD = 3.0 V, f = 869.525 MHz if nothing else is stated. All parameters are
measured on the CC1101-CC1190EM 869 MHz reference design [3] with a 50 Ω load.
23.0
Output Power [dBm]
21.0
19.0
17.0
15.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Temperature [C]
0x54, 2V
0x54, 3V
0x54, 3.6V
Figure 4.13. Typical Output Power vs. Temperature and Power Supply Voltage. PATABLE
= 0x54
21.0
Output Power [dBm]
19.0
17.0
15.0
13.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Temperature [C]
0x57, 2V
0x57, 3V
0x57, 3.6V
Figure 4.14. Typical Output Power vs. Temperature and Power Supply Voltage. PATABLE
= 0x57
Page 14 of 22
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Application Note AN094
165.0
160.0
155.0
150.0
Transmit Current [mA]
145.0
140.0
135.0
130.0
125.0
120.0
115.0
110.0
105.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Temperature [C]
0x54, 2V
0x54, 3V
0x54, 3.6V
Figure 4.15. Typical TX Current Consumption vs. Temperature and Power Supply Voltage.
PATABLE = 0x54
145.0
140.0
135.0
Transmit Current [mA]
130.0
125.0
120.0
115.0
110.0
105.0
100.0
95.0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Temperature [C]
0x57, 2V
0x57, 3V
0x57, 3.6V
Figure 4.16. Typical TX Current Consumption vs. Temperature and Power Supply Voltage.
PATABLE = 0x57
Page 15 of 22
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Application Note AN094
20
15
869,354839 MHz
16,163 dBm
10
5
0
-5
Level in dBm
-10
-15
-20
-25
-30
Spurious limit ETSI
1,738950000 GHz
-36,144 dBm
-35
2,608550000 GHz
-38,013 dBm
3,412150000 GHz
-40,821 dBm
-40
4,330678750 GHz
-45,726 dBm
-45
-50
-55
-60
860
1500
2000
2500
3000
3500
4000
4390
Frequency in MHz
Figure 4.17. Typical Radiated Fundamental and Spurious Emission Measured at Angle
with Highest Spurious Emissions. PATABLE = 0x54
Page 16 of 22
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Application Note AN094
20
10
0
-10
-20
-30 dBm
-30
-36 dBm
-36 dBm
-40
-50
-60
8.675
8.68
8.685
8.69
8.695
8.7
8.705
8.71
8.715
8
x 10
Figure 4.18. Typical Modulation Bandwidth, 38.4 kbps, PATABLE = 0x57. Measured with
Resolution Bandwidth According to ETSI EN 300 220-1 [4]
Page 17 of 22
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Application Note AN094
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 SMT-03
Rohde & Schwarz SMIQ 06B
Rohde & Schwarz FSQ 26
Agilent E3631A
Keithley 2000
Maury MT986EU32
Table 5.1. Measurement Equipment
6
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 6.1. CC1190 Control Logic
There are different ways of controlling the CC1190 mode of operation in a CC1101-CC1190
design.
•
•
Using CC1101 GDO0 and GDO27 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 6.1 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.
7
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 AN094
VDD_LNA
VDD_PA1
PA_OUT
VDD_PA2
VDD
VDD
PA_IN
RF_P
SAW
LNA_OUT
RF_N
CC110x/CC111x
CC1190
TR_SW
GDOx
PA_EN
LNA_EN
BIAS
LNA_IN
HGM
Connected to MCU
Connected to
VDD/GND/MCU
Figure 6.1. Simplified CC11xx-CC1190 Application Circuit
7
CC1101 Register Settings
It is possible to improve the CC1101 phase noise above approximately 200 kHz offset at the
cost of increased spurs at RF ± crystal frequency/2 by changing the FIFOTHR and TEST1
register settings. These settings are not used for the CC1101 standalone design due to the
increased spur level, but since a SAW filter is used in the CC1101-CC1190 design, the spurs
will be attenuated sufficiently to meet EN 300 220 spurious emission requirements. Improving
the CC1101 phase noise reduces the modulation bandwidth for a given output power and
allows operation up to +18 dBm output power.
For a given data rate a CC1101 design and a CC1101-CC1190 design can use the same
register settings except for registers FIFOTHR and TEST1. The register values listed in Table
7.1 need to be used for optimum performance. The same register settings cannot be used in
both TX and RX.
CC1101 Register
FIFOTHR
TEST1
Setting TX
0xC7
0x2D
Setting RX
0x47
0x35
Table 7.1. Recommended Register Settings for the CC1101-CC1190 Design
8
SmartRF Studio and SmartRF04EB / TrxEB
The CC1101-CC1190EM 869 MHz together with SmartRF™ Studio 7 software [6] and
SmartRF04B or TrxEB can be used to evaluate performance and functionality.
8.1
SmartRF Studio
The CC1101-CC1190 can be configured using the SmartRF Studio 7 software [6]. The
SmartRF Studio software is highly recommended for obtaining optimum register settings. The
recommended register settings for RX and TX in Table 4.1 are implemented in SmartRF
Studio 7. 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 8.1.
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Application Note AN094
Figure 8.1. SmartRF Studio 7 [6] User Interface
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 8.1.
8.2
SmartRF04EB / TRxEB
If the SmartRF04B 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 8.2. 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 8.2, where the red wire is the positive supply and the black wire is GND. With
the test setup in Figure 8.2 the SmartRF04B 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
SmartRF04B is connected to a regulated 3.3 V supply the signals going from CC1101CC1190 to SmartRF04B (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 8.2 is therefore
limited to 3.0 V to 3.6 V.
Figure 8.2. 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.
Page 20 of 22
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Application Note AN094
9
Reference Design
The CC1101-CC1190EM 869 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.
9.1
Power Decoupling
Proper power supply decoupling must be used for optimum performance. The capacitors
C27-C29 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.
9.2
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. C30 works as
a DC-block.
The layout and component values need to be copied exactly to obtain the same performance
as presented in this application note.
9.3
Bias Resistor
R141 is a bias resistor. The bias resistor is used to set an accurate bias current for internal
use in the CC1190.
9.4
Crystal
There are spurs appearing at N times the reference frequency (= N x crystal frequency/2).
These spurs are also folded around the carrier. The further away in Hz the spurs are from the
carrier the lower they will be in amplitude. For operation at 869.525 MHz the spur closest to
the carrier will be at 864 MHz when using a 27 MHz crystal and at 871 MHz when using a 26
MHz crystal. A 27 MHz crystal frequency is recommended for the CC1101-CC1190 design.
9.5
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 EN 300 220. The SAW
filter is matched to the CC1190 PA input/LNA output impedance using a series inductor and a
shunt capacitor.
9.6
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 869 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].
Page 21 of 22
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Application Note AN094
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.
10 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 EN 300 220 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.
11 References
[1]
CC1101 Datasheet (SWRS061.pdf)
[2]
CC1190 Datasheet (SWRS089.pdf)
[3]
CC1101–CC1190EM 869 MHz Reference Design (SWRR075.zip)
[4]
ETSI EN 300 220 V2.3.1: Electromagnetic compatibility and Radio spectrum Matters
(ERM); Short Range Devices (SRD); Radio equipment to be used in the 25 MHz to 1000
MHz frequency range with power levels ranging up to 500 mW”
[5]
CEPT/ERC/Recommendation 70-03: “Relating to the use of Short Range Devices (SRD)”
[6]
SmartRF™ Studio 7 (SWRC176.zip)
12 General Information
12.1 Document History
Revision
SWRA356
Date
2011.01.10
Description/Changes
Initial release.
Page 22 of 22
SWRA356
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