Application Note No. 051

A pp l ic a t io n N o t e, R e v . 2. 0 , J a n. 2 00 7
A p p li c a t i o n N o t e N o . 0 5 1
SIEGET45 - Low Noise Amplifier with BFP520
T r a n s i s t o r a t 1 .9 G H z
R F & P r o t e c ti o n D e v i c e s
Edition 2007-01-08
Published by
Infineon Technologies AG
81726 München, Germany
© Infineon Technologies AG 2009.
All Rights Reserved.
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Application Note No. 051
SIEGET45 - Low Noise Amplifier with BFP520 Transistor at 1.9 GHz
Revision History: 2007-01-08, Rev. 2.0
Previous Version:
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Trademarks
SIEGET® is a registered trademark of Infineon Technologies AG.
Application Note
3
Rev. 2.0, 2007-01-08
Application Note No. 051
SIEGET®45 - Low Noise Amplifier with BFP520 Transistor at 1.9 GHz
1
SIEGET®45 - Low Noise Amplifier with BFP520 Transistor at
1.9 GHz
This application note describes an example of a Low Noise Amplifier with the BFP520 (5th Generation, SOT343)
SIEGET®45-line. Improved performance in Gain (16 dB) and OIP3 (15 dBm) are the outstanding features at
low current IC = 7 mA (@ VCC = 2 V). Consider while designing, the device shows potential instability in the
frequency range around 1 GHz. Due to the hard stability matching conditions the 2nd example is still stable over
the whole frequency range. The 1st example is unstable at 1 GHz nevertheless the gain exceeds 16.5 dB, noise
figure ~ 1.4 dB.
Table 1
Simulation and Measurement results
Data @ 1.9 GHz
Simulation result
Measurement result
Gain (S21)
16 dB
16.5 dB
RLIN |S11|
RLout |S22|
IP3
NF
13 dB
> 11 dB
17 dB
> 20 dB
-
15 dBm
1.5 dB
1.5 dB
DC Supply
C8
C5
R5
R3
C7
R4
C3
C6
R2
L3
L1
L2
R1
C4
RFout
l1
l1
C1
l1
RFin
C2
optional
BFP520
lE
C9
optional
Striplines
l1/λ 0 = 1.13 10-2
lΕ /λ 0 = 0.9 10-2
lE
ZL ~ 72Ω
ZL ~ 72Ω
AN051_application.vsd
Figure 1
Schematic of the BFP520 Application @ 1.95 GHz
Application Note
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Rev. 2.0, 2007-01-08
Application Note No. 051
SIEGET®45 - Low Noise Amplifier with BFP520 Transistor at 1.9 GHz
1.1
PCB Layout and Component Placement
Fixed components: J1: connector / J2: switch / C8: 4.7 uF (Elko)
AN051_application_board.vsd
Figure 2
Application board (scale 3:1) - original size 23 x 35 mm
AN051_board_design.vsd
Figure 3
Board design - Top Layer and Layer-2 - scale 1:1
Top layer
Top side
0.2mm (FR4)
doubleside Cu 35µ
Layer 2
0.51mm (FR4)
Bottom layer
Bottom side
Cu 70µ
A N051_PCB_cross_section.vsd
Figure 4
PCB cross section
Application Note
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Application Note No. 051
SIEGET®45 - Low Noise Amplifier with BFP520 Transistor at 1.9 GHz
1.2
Circuit modeling and simulation
schematic NASSE 1.75, simulated with APLAC 7.02
08/1998, Munich
MSub FR4
ER = 4.16
H = 0.2m
RHO = 1
T = 0.034m
TAND = 0.02
Gradient Optimization
Goal NoiseFigure Between 1.4 1.5
Goal S_K GT 1.4
Goal MagdB(S(1,1)) Between -10 -15
Goal MagdB(S(2,2)) Between -10 -15
Goal MagdB(S(2,1)) Between 15 19
C5
R3
C3
L1
Le2
R1
Port_01
1
6
W = 0.19m
L = Le5
Le5
7
W = 0.19m
L = Le6
L2
Le4
W =0.19m
L =Le2
RFin
W =0.19m
L = Le1
2 NPort_01
E1
Le7
9
C4
RFout
Port_02
Via_E03
C9
3
8
W = 0.19m
L = Le7
W =0.19m
L = Le4
Le1
L3
Le6
5
C1
C6
DIAM = 0.3m
E2
LE12
C9 optional 0.2 ... 0.9 pF
depend on the physical
and geometrical board
properties
LE21
W =0.19m
L =LE12
Via_E1
W =0.19m
L =LE12
Via_E2
DIAM = 0.3m
DIAM = 0.3m
AN051_Simulation_circuit.vsd
Figure 5
RF Simulation Circuit of the BFP520 Application
Final analysis
APLAC 7.04 User: Siemens AG Aug 27 1998
2.00
K
1.50
[1]
1.00
0.50
0.00
1.000G
1.375G
S_K
NoiseFigure
1.750G
f [Hz]
2.125G
2.500G
S_u
AN051_Noise_Figure_K .vsd
Figure 6
Noise Figure, Stability K (S_k) µ (S_u)
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Rev. 2.0, 2007-01-08
Application Note No. 051
SIEGET®45 - Low Noise Amplifier with BFP520 Transistor at 1.9 GHz
Final analysis
APLAC 7.04 User: Siemens AG Aug 27 1998
2.00
K
1.50
[1]
1.00
0.50
0.00
1.000G
1.375G
S_K
NoiseFigure
1.750G
f [Hz]
2.125G
2.500G
S_u
AN051_input_output_matching1.vsd
Figure 7
Input and output matching
Final analysis
APLAC 7.04 User: Siemens AG Aug 27 1998
30.00
Gain
25.00
[dB]
20.00
15.00
10.00
1.000G
1.375G
MagdB(S(2,1))
1.750G 2.125G
f [Hz]
dB(S_MSG)
2.500G
AN051_maxium_stable_gain.vsd
Figure 8
Maximum stable gain and transducer gain
Final analysis
APLAC 7.04 User: Siemens AG Aug 27 1998
0.5
2.0
-0.5
-2.0
0.0 0.2
S(1,1)
1.0
5.0
S(2,2)
AN051_input_output_matching2.vsd
Figure 9
Input and output matching
Application Note
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Rev. 2.0, 2007-01-08
Application Note No. 051
SIEGET®45 - Low Noise Amplifier with BFP520 Transistor at 1.9 GHz
1.3
1stapplication circuit measurement results
Stable under proved condition (50 Ω); best noise and performance. The application shows potential instability at
1 GHz.
Table 2
Components of 1st application
Component Value
C1
15 pF
1)
C2
Input match
Improve stability
1)
C3
15 pF
C4
100 pF1)
C4
100 pF1)
15 pF
1)
C7
68 pF
1)
C8
1)
C6
Comment
L1
L2
12 nH
Comment
2)
2.2 nH
2)
2)
L3
15 nH
R1
27 Ω3)
R2
18 Ω
3)
R3
33 Ω
3)
R4
33 Ω3)
R5
0 Ω3)
Input match
Output match
Output match
Output match
1 nF
C9
Component Value
Improve stability
Improve stability
Bias; IC= 6 mA
VCC = 2 V
1) Murata
2) Toko 0402
3) S & M 0402
Application Note
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Rev. 2.0, 2007-01-08
Application Note No. 051
SIEGET®45 - Low Noise Amplifier with BFP520 Transistor at 1.9 GHz
CH1 S11
log MAG
5 dB/
REF 0 dB
CH1 S21
2_:-11.116 dB
log MAG
5 dB/
REF 0 dB
1_:-11.014 dB
1.9000 GHz
C2
2_: 16.51 dB
1.963 360 000 GHz
1.963 360 000 GHz
1_: 16.85 dB
1.9000 GHz
C2
Avg
16
Avg
16
2
2
1
1
START 0.100 000 000 GHz
CH1 S21
log MAG
START 0.100 000 000 GHz
STOP 2.500 000 000 GHz
5 dB/
REF 0 dB
CH1 S22
2_: 16.51 dB
log MAG
5 dB/
REF 0 dB
2_:-29.879 dB
1.963 360 000 GHz
1.963 360 000 GHz
1_: 16.85 dB
1.9000 GHz
C2
STOP 2.500 000 000 GHz
1_:-35.013 dB
1.9000 GHz
C2
Avg
16
Avg
16
2
1
2
START 0.100 000 000 GHz
START 0.100 000 000 GHz
STOP 2.500 000 000 GHz
STOP 2.500 000
1 000 GHz
AN051_1appl_circuit_measurement_results.vs
Figure 10
Measurement results of 1st application
Application Note
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Rev. 2.0, 2007-01-08
Application Note No. 051
SIEGET®45 - Low Noise Amplifier with BFP520 Transistor at 1.9 GHz
Noise figure vs. frequency
3
2.8
2.6
F = 1960MHz
NF = 1.49dB (Icc = 6mA)
NF = 1.52dB (Icc = 7mA)
NF [dB]
2.4
2.2
2
1.8
1.6
1.4
1.2
1
900
Icc = 6mA
Icc = 7mA
1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100
f [MHz]
AN051_Noise_Figure(f).vsd
Figure 11
Noise Figure (VCC = 2 V, TC = 25 °C)
1.4
2nd application circuit measurement results
Absolutely stable over the whole frequency range (k > 1, 0.1... 2.5 GHz, see stability circles in Figure 12 and
Figure 13). Less performance in noise figure (1.5 dB) and gain (15 dB) than the application example above.
Table 3
Components of 1st application
Component Value
C1
15 pF
Comment
1)
C2
C3
15 pF
100 pF
C4
100 pF
1)
C6
15 pF
1)
C7
68 pF
1)
C8
1)
1 nF
C9
0.5 pF1)
C4
Comment
2)
Input match
L1
6.8 nH
Improve stability
L2
1.2 nH2)
Output match
L3
5.6 nH
2)
Output match
R1
22 Ω3)
R2
18 Ω
3)
R3
33 Ω
3)
R4
33 Ω3)
R5
0 Ω3)
1)
1)
Component Value
Input match
Output match
Improve stability
Improve stability
Bias; IC= 6 mA
VCC = 2 V
1) Murata
2) Toko 0402
3) S & M 0402
Application Note
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Rev. 2.0, 2007-01-08
Application Note No. 051
SIEGET®45 - Low Noise Amplifier with BFP520 Transistor at 1.9 GHz
AN051_source_stability_circules.vsd
Figure 12
Source stability circules
AN051_load_stability_circules.vsd
Figure 13
Load stability circules
Stability definitions:
S_D
the stability factor k
S_D
the magnitude of the S-matrix determinant |∆|
S_u
a stability factor µ (s)
AN051_stability_analysis.vsd
Figure 14
Stability analysis
Application Note
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Rev. 2.0, 2007-01-08
Application Note No. 051
SIEGET®45 - Low Noise Amplifier with BFP520 Transistor at 1.9 GHz
CH1 S11
log MAG
5 dB/
REF 0 dB
CH1 S12
2_:-16.014 dB
log MAG
5 dB/
REF 0 dB
1.960 000 000 GHz
1_:-16.745 dB
1.9000 GHz
C2
2_:-24.991 dB
1.960 000 000 GHz
1_:-25.158 dB
1.9000 GHz
C2
Avg
16
Avg
16
2
1
2
1
START 0.100 000 000 GHz
CH1 S21
log MAG
STOP 2.500 000 000 GHz
5 dB/
REF 0 dB
START 0.100 000 000 GHz
CH1 S22
2_: 14.74 dB
log MAG
1.960 000 000 GHz
5 dB/
REF 0 dB
2_:-12.376 dB
1.960 000 000 GHz
1_: 15.062 dB
1.9000 GHz
C2
STOP 2.500 000 000 GHz
1_:-13.198 dB
1.9000 GHz
C2
Avg
16
Avg
16
2
2
1
1
START 0.100 000 000 GHz
STOP 2.500 000 000 GHz
START 0.100 000 000 GHz
STOP 2.500 000 000 GHz
AN051_2appl_circuit_measurement_results.vsd
Figure 15
Measurements results of 2nd application
Application Note
12
Rev. 2.0, 2007-01-08