Download BDTIC www.BDTIC.com/infineon Application Note No. 020

A pp li c at i on N ot e , R ev . 2. 0 , N ov . 2 00 6
A p p li c a t i o n N o t e N o . 0 2 0
A Lo w - N o i s e - A m p l i f i e r a t 1 . 9 G H z u s i n g B F P 4 0 5
BDTIC
R F & P r o t e c ti o n D e v i c e s
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BDTIC
Edition 2006-11-08
Published by
Infineon Technologies AG
81726 München, Germany
© Infineon Technologies AG 2009.
All Rights Reserved.
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Application Note No. 020
A Low-Noise-Amplifier at 1.9 GHz using BFP405
Revision History: 2006-11-08, Rev. 2.0
Previous Version: 2000-07-27
Page
Subjects (major changes since last revision)
All
Document layout change
BDTIC
Trademarks
SIEGET® is a registered trademark of Infineon Technologies AG.
Application Note
3
www.BDTIC.com/infineon
Rev. 2.0, 2006-11-08
Application Note No. 020
Low-Noise-Amplifier at 1.9 GHz using BFP405
1
Low-Noise-Amplifier at 1.9 GHz using BFP405
This application note describes a low noise amplifier at 1.9 GHz using SIEMENS SIEGET®25 BFP405. The design
emphasis has been on achieving a low noise figure. A circuit description, schematic, PCB layout and components
list are shown below together with measured performance data.
Data at 1.9 GHz (3 V and 4.2 mA)
Gain:
16.5 dB
IP3out:
NF:
RLin-out
5 dBm
1.75 dB
>10 dB
BDTIC
+3V
C5=100pF
C6=10nF
R1=100 Ohm
C4=33pF
R3=39k
TrL6
C3=33pF
C2=10pF
RFout
TrL5
C1=22pF
RFin
TrL1
TrL4
R2=10 Ohm
Tr1=BFP405
TrL2
TrL3
AN020_application.vsd
Figure 1
Application
This amplifier at 1.9 GHz has been realized by using microstrip lines as matching elements. The design offers a
good compromise between high IIP3 values, low noise figure and high return loss.
In order to optimize the design for a particular application please observe the following points:
•
•
•
•
•
The layout size can be reduced by using chip-inductors instead of the microstrip lines TrL1 and TrL6
Improved stabilization behaviour versus temperature and reduced variation in amplifier performance due to the
device‘s Beta (current gain) distribution can be achieved by using an active bias circuit. Such a circuit is
available as a single device from Infineon - BCR400W. For further information please refer to Application Note
No.14. However, the resistors R1 and R3 are sufficient in most applications for stabilization purposes.
This circuit is not optimized, for low noise figure, it is a first step to a good design. The measured figures include
losses of SMA-connectors and the relatively high loss of the microstrip lines on the epoxy-board.
The use of teflon material would provide an improvement of ≅ 0.1 dB.
Resistor R2 is used to improve RF-circuit-stability and return loss values at the output. It also affects the output
intermodulation performance.
Application Note
4
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Rev. 2.0, 2006-11-08
Application Note No. 020
Low-Noise-Amplifier at 1.9 GHz using BFP405
scale 1:1
dim.: 25mm x 20mm
SIEMENS HL EH
39k
100
33pF
33pF
BDTIC
10 nF
100pF
22pF
plated thru
holes d=0.5mm
BFP405
10pF
10
AN020_PCB_Layout.vsd
Figure 2
PCB Layout and Component Placement
Application Note
5
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Rev. 2.0, 2006-11-08
Application Note No. 020
Low-Noise-Amplifier at 1.9 GHz using BFP405
Table 1
Component
Component
Value
Unit
Comment
R1
100
Ω
0603
Bias / collector-resistance / VR1 ≅ 0.5 V 0603
R2
10
Ω
0603
To improve stability and output return loss 0603
R3
39
kΩ
0603
Bias / base-resistor 0603
C1
22
pF
0603
Input match 0603
C2
10
pF
0603
Output match 0603
C3
33
pF
0603
RF-short 0603
C4
33
pF
C5
100
pF
Output match
0603
RF-short 0603
BDTIC
C6
10
nF
Tr1
0603
RF-short 0603
SOT343
SIEGET® BFP405 SOT343
TrL1
Input match, w = 0.3 mm
TrL2
Input match, w = 0.95 mm
TrL3
Input match, w = 0.95 mm
TrL4
Output match, w = 0.95 mm
TrL5
Output match, w = 0.95 mm
TrL6
Output match, w = 0.3 mm
Substrate
Application Note
h = 0.5 mm, εr = 4.5
FR4
6
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Rev. 2.0, 2006-11-08
Application Note No. 020
Low-Noise-Amplifier at 1.9 GHz using BFP405
Measurements
S21
10.000 dB/DIV
LOG MAG.
S12
LOG MAG.
10.000 dB/DIV
1
BDTIC
1
S11
3.000000
GHz
0.100000
0.100000
10.000 dB/DIV
LOG MAG.
S22
10.000 dB/DIV
LOG MAG.
1
1
GHz
0.100000
1
3.000000
GHz
3.000000
0.100000
GHz
3.000000
1.9 GHz
AN020_M easurem ents.vsd
Figure 3
Measurements
Application Note
7
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Rev. 2.0, 2006-11-08