Download BDTIC Application Note No. 015

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 5
L o w - N o i s e- A m p l i f i e r o p t i m i z e d fo r m i n i m u m N o i s e
F i g u r e a t 1 . 9 G H z u s i ng B F P 42 0
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 2006-11-14
Published by
Infineon Technologies AG
81726 München, Germany
© Infineon Technologies AG 2009.
All Rights Reserved.
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Application Note No. 015
Low-Noise-Amplifier optimised for minimum Noise Figure at 1.9 GHz using BFP420
Revision History: 2006-11-14, Rev. 2.0
Previous Version:
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Subjects (major changes since last revision)
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Document layout change
BDTIC
Trademarks
SIEGET® is a registered trademark of Infineon Technologies AG.
Application Note
3
www.BDTIC.com/infineon
Rev. 2.0, 2006-11-14
Application Note No. 015
Low-Noise-Amplifier optimised for minimum Noise Figure at 1.9 GHz using
1
Low-Noise-Amplifier optimised for minimum Noise Figure at
1.9 GHz using BFP420
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 SIEMENS SIEGET®25 BFP420. This circuit is optimised
for low noise figure values.
Data at 1.9 GHz (3 V and 5 mA)
Gain:
13 dB
IP3out:
NF::
RLin:
RLout:
10 dB
1.4 dB
BDTIC
>7 dB
>20 dB
The amplifier application circuit has been optimised to achieve optimum noise figure and good stability at 1.9 GHz,
combined with low operating current and voltage for use in handheld equipment.
The transistor is matched using microstrip lines at input and output in conjunction with capacitors to ground. The
added emitter inductance reduces gain but it provides the best overall matching conditions for maximum gain and
minimum noise figure. The active bias controller BCR400W is used to provide bias stability over the operating
temperature range. For additional information on this part please refer to application note No.014. The collector
resistor is used for increase stability for the RF-transistor and omits the need to use λ/4 transmission lines for
biasing. In order to avoid AF oscillations for the BCR400W, the blocking capacitor at the base of the RF transistor
should be at least ten times the value used at collector.
IC1
2
C5=4.7µF
1
BCR400W
C4=1nF
R3=150 Ohm
C7=1nF
C3=22pF
C6=22pF
R2=150 Ohm
R1=10k
RFin
+3V
3
4
RFout
TrL4
TrL1
C2=0.8pF
C1=0.5pF
Tr1=BFP420
TrL2
TrL3
AN015_application.vsd
Figure 1
Schematic Diagram
Application Note
4
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Rev. 2.0, 2006-11-14
Application Note No. 015
Low-Noise-Amplifier optimised for minimum Noise Figure at 1.9 GHz using
25mm x 20mm
150 Ohm
0 Ohm
BDTIC
4.7µF
BCR400W
1 nF
22 pF
1 nF
0.5 pF
22 pF
150 Ohm
10kOhm
0.8 pF
BFP420
AN015_PCB_Layout.vsd
Figure 2
PCB Layout and Component Placement
Application Note
5
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Rev. 2.0, 2006-11-14
Application Note No. 015
Low-Noise-Amplifier optimised for minimum Noise Figure at 1.9 GHz using
Table 1
Component
Component
Value
Unit
Size
Comment
R1
10
kΩ
0603
Bias
R2
150
Ω
0603
To improve stability and output return loss
R3
150
Ω
0603
Bias resistor for BCR400W / collector current
C1
0.5
pF
0603
Input match
C2
0.8
pF
0603
Output match
C3
22
pF
0603
RF-short
C4
1
nF
0603
RF-short
C5
4.7
µF
0603
RF-short
BDTIC
C6
10
nF
0603
RF-short
C7
22
pF
0603
RF-short
C8
1
nF
0603
RF-short
SOT343
SIEGET® BFP420
Tr1
TrL1
Input match
TrL2
Emitter-microstrip-line
TrL3
Emitter-microstrip-line
TrL4
Output match
IC1
Substrate
Application Note
SOT343
BCR400W, active bias controller
h = 0.5 mm, εr = 4.5
FR4
6
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Rev. 2.0, 2006-11-14
Application Note No. 015
Low-Noise-Amplifier optimised for minimum Noise Figure at 1.9 GHz using
Measurements
10.000 dB/DIV
S21 LOG MAG.
S12 LOG MAG.
10.000 dB/DIV
1
BDTIC
1
S11
0.100000
3.000000
GHz
0.100000
LOG MAG.
10.000 dB/DIV
S22
3.000000
GHz
LOG MAG.
10.000 dB/DIV
1
1
GHz
0.100000
1
3.000000
0.100000
3.000000
GHz
1.9 GHz
AN015_M easurem ents.vsd
Figure 3
Measurements
Application Note
7
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Rev. 2.0, 2006-11-14