A pp li c at i on N ot e , R ev . 1. 2 , S e pt e m be r 2 00 7
A p p li c a t i o n N o t e N o . 1 2 0
1.8 V Low Noise Amplifier for 1575 MHz GPS
A p pl i c a t i o n s u s i n g th e S i G e :C B F P 7 4 0 F T r a n s i s t o r
R F & P r o t e c ti o n D e v i c e s
Edition 2007-09-03
Published by
Infineon Technologies AG
81726 München, Germany
© Infineon Technologies AG 2009.
All Rights Reserved.
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Application Note No. 120
Application Note No. 120
Revision History: 2007-09-03, Rev. 1.2
Previous Version: 2005-08-10, Rev. 1.1
Page
Subjects (major changes since last revision)
All
Document layout change
Application Note
3
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
1
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the
SiGe:C BFP740F Tranistor
Applications
•
1575.42 MHz GPS
Overview
•
•
•
•
BFP740F in TSFP-4 package is evaluated for a GPS LNA application. Note TSFP-4 package is only
1.4 x 1.2 x 0.55 mm high.
Design Goals: Gain = 20 dB min, Noise Figure = 0.8 dB max, Input / Output Return Loss 10 dB or better,
current < 10 mA from a 1.8 V power supply
Printed Circuit Board used is Infineon Part Number 740F-080404 Rev A. Standard FR4 material is used in a
three-layer PCB. Please refer to cross-sectional diagram below.
Low-cost, standard "0402" case-size SMT passive components are used throughout. Please refer to
schematic and Bill Of Material. The LNA is unconditionally stable from 5 MHz to 8 GHz.
Total PCB area used for the single LNA stage is 40 mm². Total Parts count, including the BFP740F transistor,
is 11.
Summary of Results
T = 25 °C, Network Analyzer Source Power ≈ -30 dBm
Table 1
Summary of Data
Frequency
MHz
dB[s11]² dB[s21]² dB[s12]² dB[s22]² NF *
dB
IIP3
OIP3
IP1dB
OP1dB
dBm
dBm
dBm
dBm
1575.42
10.8
+0.2
+19.9
-17.3
+1.4
19.7
27.1
12.8
0.76
PCB loss is not extracted, e.g. reference plane of measurement is at PCB input RF SMA connector. If PCB loss
were extracted, noise figure result would improve by 0.1-0.2 dB, e.g. NF result would be lower / better.
PCB Cross - Section Diagram
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Figure 1
PCB - Cross Sectional Diagram
Application Note
4
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
TSFP-4 package details (dimensions in millimeters)
Note maximum package height is 0.59 mm / 0.023 inch
0.2 ±0.05
1
3
1.2 ±0.05
0.2 ±0.05
4
0.55 ±0.04
2
0.2 ±0.05
10˚ MAX.
0.8 ±0.05
1.4 ±0.05
0.15 ±0.05
0.5 ±0.05
0.5 ±0.05
Figure 2
GPX01010
TSFP-4 package details
Recommended Soldering Footprint for TSFP-4 given below (dimensions in millimeters). Device package is to be
oriented as shown in above drawing (e.g. orient long package dimension horizontally on this footprint).
0.9
0.45
0.35
0.5
0.5
HLGF1011
Figure 3
TSFP-4 package - Soldering Footprint
Application Note
5
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Bill of Material
Table 2
Bill of Material
Reference
Designator
Value
Manufacturer
Case
Size
Function
C1
0.1 µF
Various
0402
DC blocking, input. Also, using cap above selfresonant frequency makes it slightly inductive,
slightly improving input match.
C2
2.7 pF
Various
0402
DC block, output. Also influences output and input
impedance match.
C3
0.1 µF
Various
0402
Decoupling, low frequency. Also improves ThirdOrder Intercept.
C4
3.3 pF
Various
0402
Decoupling at collector; also influence on stability
and output match.
C5
0.1 µF
Various
0402
Low frequency decoupling, slightly improves
Third Order Intercept.
L1
9.1 nH
Murata LQP15M
series chip inductor
0402
RF choke at input, also influences input
impedance match
L2
4.7 nH
Murata LQP15M
series chip inductor
0402
RF choke + impedance match at output
R1
10 Ω
Various
0402
Improves low frequency stability e.g. K > 1
R2
22 kΩ
Various
0402
Brings bias current / voltage into base of
transistor.
R3
30 Ω
Various
0402
Provides some negative feedback for DC bias /
DC operating point to compensate for variations
in transistor DC current gain, temperature
variations, etc.
Q1
-
Infineon
Technologies
TSFP-4
BFP740F B7HFe SiGe:C Ultra-Low Noise HBT
Transistor
J1, J2
-
Johnson
142-0701-841
-
RF input / output connectors
J3
-
Amp 5 pin header
MTA-100 series
640456-5 (standard
pin plating) or
641215-5 (gold
plated pins)
-
DC connector
Pins 1, 5 = Ground
Pin 3 = VCC
Pins 2, 4 = no connection
Application Note
6
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Schematic Diagram for 1575 MHz GPS LNA
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Schematic Diagram
Application Note
7
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Noise Figure, Plot, Center of Plot (x-axis) is 1575 MHz.
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Figure 5
Noise Figure
Application Note
8
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Noise Figure, Tabular Data
From Rhode & Schwarz FSEK3 + FSEM30 + System Preamplifier
Table 3
Noise Figure
Frequency
Noise Figure
1075 MHz
0.93 dB
1125 MHz
0.89 dB
1175 MHz
0.87 dB
1225 MHz
0.84 dB
1275 MHz
0.81 dB
1325 MHz
0.82 dB
1375 MHz
0.80 dB
1425 MHz
0.80 dB
1475 MHz
0.78 dB
1525 MHz
0.76 dB
1575 MHz
0.76 dB
1625 MHz
0.74 dB
1675 MHz
0.75 dB
1725 MHz
0.77 dB
1775 MHz
0.77 dB
1825 MHz
0.78 dB
1875 MHz
0.78 dB
1925 MHz
0.80 dB
1975 MHz
0.83 dB
2025 MHz
0.83 dB
2075 MHz
0.81 dB
Application Note
9
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Scanned Image of PC Board
Figure 6
Image of PC Board
Application Note
10
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Scanned Image of PC Board, Close-In Shot
Total PCB area used is approximately 40 mm²
Figure 7
Image of PC Board, Close-In Shot
Application Note
11
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Amplifier Stability
T = 25 °C, VCC = 1.8 V, VCE = 1.4 V, I = 9.6 mA
Stability Factor "K" is shown below from "screen shot" taken from Rohde and Schwarz ZVC network analyzer. ZVC
Vector Network Analyzer calculates and plots K in real time, from measured S parameters.Note that minimum K
value is 0.974 at 1.1 GHz, which is ≈ 1, for practical purposes; the amplifier is unconditionally stable over 5 MHz
to 8 GHz range.
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Plot of Stability K(f)
Application Note
12
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Gain Compression at 1575 MHz
T = 25 °C, VCC = 1.8 V, VCE = 1.4 V, I = 9.6 mA
Amplifier is checked for 1 dB compression point. An Aglient power meter was used to ensure accurate power
levels are measured (as opposed to using Vector Network Analyzer in “Power Sweep” mode).
Output P1dB ≅ +1.4 dBm; Input P1dB = +1.4 dBm - (Gain - 1 dB) = +1.4 dBm - 18.7 dB = -17.3 dBm
Table 4
Gain Compression (1575 MHz)
POUT, dBm
Gain, dBm
-10.0
19.7
-9.0
19.7
-8.0
19.7
-7.0
19.6
-6.0
19.6
-5.0
19.6
-4.0
19.6
-3.0
19.5
-2.0
19.4
-1.0
19.3
0.0
19.2
+1.0
18.9
+2.0
18.5
+3.0
17.6
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Figure 9
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Plot of Gain Compression @ 1575 MHz
Application Note
13
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Please Note - all plots are taken from Rhode and Schwarz ZVC Network Analyzer, T = 25 °C,
source power ≈ -30 dBm
Input Return Loss, Log Mag
5 MHz to 8 GHz Sweep
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Plot of Input Return Loss
Application Note
14
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Input Return Loss, Smith Chart
Reference Plane = Input SMA Connector on PC Board
5 MHz to 8 GHz Sweep
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Smith Chart of Input Return Loss
Application Note
15
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Forward Gain
5 MHz to 8 GHz Sweep
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Plot of Forward Gain
Application Note
16
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Reverse Isolation
5 MHz to 8 GHz
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Plot of Reverse Isolation
Application Note
17
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Output Return Loss, Log Mag
5 MHz to 8 GHz
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Plot of Output Return Loss
Application Note
18
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
Output Return Loss, Smith Chart
Reference Plane = Output SMA Connector on PC Board
5 MHz to 8 GHz Sweep
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Smith Chart of Output Return Loss
Application Note
19
Rev. 1.2, 2007-09-03
Application Note No. 120
1.8 V Low Noise Amplifier for 1575 MHz GPS Applications using the SiGe:C
LNA Response to Two-Tone Test
Input Stimulus: f1 = 1574 MHz, f2 = 1575 MHz, -25 dBm each tone.
Input IP3 = -25 + (50.3/2) = +0.2 dBm
Output IP3 = +0.2 dBm + 19.7 dB gain = +19.9 dBm
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Figure 16
Tow-Tone Test, LNA Response (1575 MHz)
Application Note
20
Rev. 1.2, 2007-09-03