Download BDTIC Application Note No. 021

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 1
A Lo w - N o i s e - A m p l i f i e r s h o w s g o o d N o i s e F ig u r e
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
www.BDTIC.com/infineon
BDTIC
Edition 2006-11-08
Published by
Infineon Technologies AG
81726 München, Germany
© Infineon Technologies AG 2009.
All Rights Reserved.
LEGAL DISCLAIMER
THE INFORMATION GIVEN IN THIS APPLICATION NOTE IS GIVEN AS A HINT FOR THE IMPLEMENTATION
OF THE INFINEON TECHNOLOGIES COMPONENT ONLY AND SHALL NOT BE REGARDED AS ANY
DESCRIPTION OR WARRANTY OF A CERTAIN FUNCTIONALITY, CONDITION OR QUALITY OF THE
INFINEON TECHNOLOGIES COMPONENT. THE RECIPIENT OF THIS APPLICATION NOTE MUST VERIFY
ANY FUNCTION DESCRIBED HEREIN IN THE REAL APPLICATION. INFINEON TECHNOLOGIES HEREBY
DISCLAIMS ANY AND ALL WARRANTIES AND LIABILITIES OF ANY KIND (INCLUDING WITHOUT
LIMITATION WARRANTIES OF NON-INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OF ANY
THIRD PARTY) WITH RESPECT TO ANY AND ALL INFORMATION GIVEN IN THIS APPLICATION NOTE.
Information
For further information on technology, delivery terms and conditions and prices please contact your nearest
Infineon Technologies Office (www.infineon.com).
Warnings
Due to technical requirements components may contain dangerous substances. For information on the types in
question please contact your nearest Infineon Technologies Office.
Infineon Technologies Components may only be used in life-support devices or systems with the express written
approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure
of that life-support device or system, or to affect the safety or effectiveness of that device or system. Life support
devices or systems are intended to be implanted in the human body, or to support and/or maintain and sustain
and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may
be endangered.
www.BDTIC.com/infineon
Application Note No. 021
A Low-Noise-Amplifier shows good Noise Figure performance at 1.9 GHz using BFP405
Revision History: 2006-11-08, Rev. 2.0
Previous Version: 2000-07-28
Page
Subjects (major changes since last revision)
All
Document layoout 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. 021
Low-Noise-Amplifier shows good Noise Figure performance at 1.9 GHz using
1
Low-Noise-Amplifier shows good Noise Figure 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 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 4.8 mA)
Gain:
16 dB
IP3out:
NF:
RLin-out
8 dBm
1.6 dB
BDTIC
>10 dB
+3V
C5=100pF
C6=10nF
R1=100 Ohm
C4=10pF
R3=27k
TrL6
C3=10pF
C2=10pF
RFout
TrL5
C1=100pF
RFin
TrL1
TrL4
R2=12 Ohm
Tr1=BFP405
TrL2
TrL3
AN021_application.vsd
Figure 1
Schematic Diagram
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, it is only meant as 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
www.BDTIC.com/infineon
Rev. 2.0, 2006-11-08
Application Note No. 021
Low-Noise-Amplifier shows good Noise Figure performance at 1.9 GHz using
scale 1:1
dim.: 37mm x 28mm
10nF
100pF
gnd
BDTIC
100
10pF
100pF
plated thru
holes d=0.5mm
10pF
27k
10pF
BFP405
12
AN021_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. 021
Low-Noise-Amplifier shows good Noise Figure performance at 1.9 GHz using
Table 1
Component
Component
Value
Unit
Size
Comment
R1
100
Ω
0603
Bias / collector-resistance / VR1 ≅ 0.5 V
R2
10
Ω
0603
To improve stability and output return loss
R3
39
kΩ
0603
Bias / base-resistor
C1
22
pF
0603
Input match
C2
10
pF
0603
Output match
C3
33
pF
0603
RF-short
C4
33
pF
0603
Output match
C5
100
pF
0603
RF-short
BDTIC
C6
10
Tr1
nF
0603
RF-short
SOT343
SIEGET® BFP405
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 = 1 mm, εr = 4.5
FR4
6
www.BDTIC.com/infineon
Rev. 2.0, 2006-11-08
Application Note No. 021
Low-Noise-Amplifier shows good Noise Figure 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
10.000 dB/DIV
LOG MAG.
S22
10.000 dB/DIV
LOG MAG.
1
GHz
0.100000
1
3.000000
GHz
1
3.000000
0.100000
3.000000
GHz
1.9 GHz
AN021_M easurem ents.vsd
Figure 3
Measurements
Application Note
7
www.BDTIC.com/infineon
Rev. 2.0, 2006-11-08