Download BDTIC Application Note No. 019

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 1 9
A Lo w - N o i s e - A m p l i f i e r w i t h g o o d I P 3o u t p e r fo r m a n c e a t 1 . 9 G H z u s i n g B F P 40 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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www.BDTIC.com/infineon
Application Note No. 019
A Low-Noise-Amplifier with good IP3out- performance 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. 019
A Low-Noise-Amplifier with good IP3out-performance at 1.9 GHz using
1
A Low-Noise-Amplifier with good IP3out-performance 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 high output intercept point. 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 8.5 mA)
Gain:
19.5 dB
IP3out:
NF:
RLin-out
15 dBm
2.3 dB
BDTIC
>15 dB
+3V
C5=100pF
C6=10nF
R1=47 Ohm
C4=10pF
R3=18k
TrL2
C3=10pF
C2=1pF
RFout
TrL1
R2=22 Ohm
C1=10pF
RFin
Tr1=BFP405
AN019_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, high gain and return loss values.
In order to optimize the design for a particular application please observe the following points:
•
•
•
•
•
The layout size can be reduced by using chip-coils instead of the microstrip lines TrL1 and TrL2
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 values. The measured figures include losses of SMAconnectors 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
www.BDTIC.com/infineon
Rev. 2.0, 2006-11-08
Application Note No. 019
A Low-Noise-Amplifier with good IP3out-performance at 1.9 GHz using
scale 1:1
dim.: 25mm x 20mm
SIEMENS HL EH
18k
47
10 pF
100 pF
plated thru
holes d=0.5mm
BDTIC
10 nF
10 pF
10 pF
22
1 pF
BFP405
SIEMENS HL EH
AN019_PCB_Layout.vsd
Figure 2
PCB Layout and Component Placement
Application Note
5
www.BDTIC.com/infineon
Rev. 2.0, 2006-11-08
Application Note No. 019
A Low-Noise-Amplifier with good IP3out-performance at 1.9 GHz using
Table 1
Component
Component
Value
Unit
Size
Comment
R1
47
Ω
0603
Bias / collector-resistance / VR ≅ 0.5 V
R2
22
Ω
0603
To improve stability and output return loss
R3
18
kΩ
0603
Bias / base-resistor
C1
10
pF
0603
Input match
C2
1
pF
0603
Output match
C3
10
pF
0603
RF-short
C4
10
pF
C5
100
pF
Output match
0603
RF-short
BDTIC
C6
10
nF
Tr1
0603
RF-short
SOT343
SIEGET® BFP405
TrL1
Input match, w = 0.3 mm
TrL2
Output match, w = 0.3 mm
Substrate
Application Note
h = 0.5 mm, εr = 4.5; 50 Ω microstrip-line w = 0.95 mm
FR4
6
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Rev. 2.0, 2006-11-08
Application Note No. 019
A Low-Noise-Amplifier with good IP3out-performance at 1.9 GHz using
Measurements
S21
10.000 dB/DIV
LOG MAG.
S12
10.000 dB/DIV
LOG MAG.
1
BDTIC
1
S11
3.000000
GHz
0.100000
0.100000
S22
10.000 dB/DIV
LOG MAG.
LOG MAG.
10.000 dB/DIV
1
GHz
0.100000
1
Figure 3
3.000000
GHz
1
3.000000
0.100000
1.9 GHz
3.000000
GHz
AN019_M easurem ents.vsd
Measurements
Application Note
7
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Rev. 2.0, 2006-11-08