AN031

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 3 1
A L o w N o i s e A m p l i f i e r a t 1 . 9 G H z o ff e r s + 1 4 d B m
Input Intercept Point
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. 031
Application Note No. 031
Revision History: 2007-01-08, Rev. 2.0
Previous Version:
Page
Subjects (major changes since last revision)
Trademarks
SIEGET® is a registered trademark of Infineon Technologies AG.
Application Note
3
Rev. 2.0, 2007-01-08
Application Note No. 031
A Low Noise Amplifier at 1.9 GHz offers +14 dBm Input Intercept Point
1
A Low Noise Amplifier at 1.9 GHz offers +14 dBm Input Intercept
Point
This application note provides general information, print layout and list of used components, circuit layout and
measured data of a low noise amplifier at 1.9 GHz using Infineon SIEGET BFP450. The emphasis has been on
high IP3in -values
Data at 1.9 GHz (3 V and 24 mA / R1 = 33, R2 = 5.6 k)
Gain:
11 dB
IP3out:
NF:
RLin-out
14 dBm
1.9 dB
>10 dB
Data at 1.9 GHz (3 V and 15 mA / R1 = 56, R2 = 8.2 k)
Gain:
10.5 dB
IP3out:
NF:
RLin-out
10 dBm
1.8 dB
>10 dB
+3V
C5=100pF
C6=10nF
R1=33 Ohm
C4=10pF
R2=5.6k
TrL4
C3=10pF
C2=100pF
RFout
R3=33 Ohm
C1=0.8pF
TrL1
TrL3
RFin
Tr1=BFP450
TrL2
TrL5
TrL6
AN031_Application.vsd
Figure 1
Application
This amplifier at 1.9 GHz has been realized by using microstrip lines for matching purposes. It offers a good
compromise between low noise and high IIP3 values.For optimizing and improving the circuit please observe the
following abstract:
•
•
The layout size can be reduced by using chip-inductors instead of the microstrip lines TrL1 and TrL4
You are able to get a better stabilization behaviour versus temperature and a reduction of current gain
distribution problems it you add a Infineon active bias controller BCR400W. This is easily done by replacing
collector resistor R1 and by adding two capacitors. For further information please refer to application note
No 014. However the resistor R1 and R2 are sufficient in most applications for stabilization purposes.
Application Note
4
Rev. 2.0, 2007-01-08
Application Note No. 031
A Low Noise Amplifier at 1.9 GHz offers +14 dBm Input Intercept Point
•
•
The measured figures include losses of SMA-connectors and the relatively high loss of the microstrip lines on
the epoxy-board.
Resistor R3 is used get higher circuit-stability at low frequencies.
scale 1:1
dim.: 25mm x 28.5mm
10nF
100pF
10pF
33 Ohm
33 Ohm
plated thru
holes
10pF
5.6kOhm
0.8pF
100pF
BFP450
AN031_PCB_layout.vsd
Figure 2
PCB Layout and Component Placement
Application Note
5
Rev. 2.0, 2007-01-08
Application Note No. 031
A Low Noise Amplifier at 1.9 GHz offers +14 dBm Input Intercept Point
Table 1
Component
Component
Value
Unit
Size
R1
33
Ω
0603/0805 Bias / collector-resistance / VR1 ≅ 0.7 V
R2
5.6
kΩ
0603/0805 Bias
R3
33
Ω
0603/0805 To improve AF-stability
C1
0.8
pF
0603/0805 Input match
C2
100
pF
0603/0805 DC-block
C3
10
pF
0603/0805 RF-short
C4
10
pF
0603/0805 RF-short
C5
100
pF
0603/0805 RF-short
C6
10
nF
0603/0805 RF-short
Tr1
Comment
SIEGET® BFP450
SOT343
TrL1
Input match, w = 0.3 mm
TrL2
Input match, w = 0.8 mm
TrL3
Output match, w = 1.9 mm
TrL4
Output match, w = 0.3 mm
TrL5
Emitter inductance, w = 1.9 mm
TrL6
Emitter inductance, w = 1.9 mm
Substrate
Application Note
h = 1 mm, er = 4.5
FR4
6
Rev. 2.0, 2007-01-08
Application Note No. 031
A Low Noise Amplifier at 1.9 GHz offers +14 dBm Input Intercept Point
Measured data
+V = 3 Vdc / I = 24 mA (R1 = 33 Ω, R2 = 5.6 kΩ)
S21
LOG MAG.
S12
10.000 dB/DIV
LOG MAG.
10.000 dB/DIV
1
1
0.040000
S11
GHz
3.000000
0.040000
10.000 dB/DIV
LOG MAG.
S22
GHz
3.000000
10.000 dB/DIV
LOG MAG.
1
1
0.040000
1
GHz
3.000000
0.040000
GHz
3.000000
1.9 GHz
AN031_M easured_data_24m A.vsd
Figure 3
Measured data
Application Note
7
Rev. 2.0, 2007-01-08
Application Note No. 031
A Low Noise Amplifier at 1.9 GHz offers +14 dBm Input Intercept Point
Measured data
+V = 3 Vdc / I = 15 mA (R1 = 56 Ω, R2 = 8.2 kΩ)
S21
LOG MAG.
10.000 dB/DIV
S12
10.000 dB/DIV
LOG MAG.
1
1
0.040000
S11
GHz
LOG MAG.
0.040000
3.000000
10.000 dB/DIV
S22
GHz
LOG MAG.
3.000000
10.000 dB/DIV
1
1
0.040000
1
GHz
3.000000
0.040000
GHz
3.000000
1.9 GHz
AN031_M easured_data_15m A.vsd
Figure 4
Measured data
Application Note
8
Rev. 2.0, 2007-01-08
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