AN117

A pp li c at io n N o t e, R e v . 1. 3 , N ov e m be r 2 00 7
A p p li c a t i o n N o t e N o . 1 1 7
L o w N o i s e A m p l i fi e r ( L N A ) f o r 1 5 7 5 M H z ( G P S )
A p pl i c a t i o n s us i n g t h e U lt r a - L o w N o i s e S i G e : C
B FP 7 40 F Tr a ns i s t o r
R F & P r o t e c ti o n D e v i c e s
Edition 2007-11-16
Published by
Infineon Technologies AG
81726 München, Germany
© Infineon Technologies AG 2009.
All Rights Reserved.
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Application Note No. 117
Application Note No. 117
Revision History: 2007-11-16, Rev. 1.3
Previous Version: 2007-08-30, Rev. 1.2
Page
Subjects (major changes since last revision)
Tittle change
Application Note
3
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the Ultra-
1
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using
the Ultra-Low Noise SiGe:C BFP740F Transistor
Overview
•
•
•
•
BFP740F in TSFP-4 package is evaluated for a 1575 MHz GPS LNA application. Note TSFP-4 package is only
1.4 x 1.2 x 0.55 mm high. Design Goals: Gain = 17 dB min, Noise Figure = 0.8 dB max, Input / Output Return
Loss 10 dB or better, current < 8 mA from a 3.0 V power supply.
Printed Circuit Board used is Infineon Part Number 740F-0080404 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 6 GHz.
Total PCB area used for the single LNA stage is < 40 mm². Total Parts count, including the BFP740 transistor,
is 12.
Achieved ≅ 20 dB gain, 0.67 dB Noise Figure at 1575 MHz from 3.0 V supply drawing 8.2 mA. Note noise figure
result does NOT "back out" FR4 PCB losses - if the PCB loss at LNA input were extracted, Noise Figure result
would be approximately 0.1 dB lower. Input P1dB ≈ -18 dBm @ 1575 MHz. Input Third Order Intercept of -1.7 dBm
@ 1575 MHz. Further work will be done to optimize input match (presently amplifier has 9.0 dB input return loss).
PCB Cross - Section Diagram
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Figure 1
PCB - Cross Sectional Diagram
Application Note
4
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraTSFP-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 (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. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraSummary of LNA Data
T = 25 °C, network analyzer source power = -25 dBm
Table 1
Summary of LNA Data
Parameter
Result
Comments
Frequency Range
1575.42 MHz
GPS “L1” carrier frequency
DC Current
8.2 mA @ 3.0 V
DC Voltage, VCC
3.0 V
Collector-Emitter Voltage, VCE
2.7 V
Gain
19.8 dB @ 1575 MHz
Noise Figure
0.67 dB @ 1575 MHz
Input P1dB
-18.0 dBm @ 1575 MHz
Output P1dB
+0.8 dBm @ 1575 MHz
rd
Input 3 Order Intercept
-1.7 dBm @ 1575 MHz
Input Return Loss
9.0 dB @ 1575 MHz
Output Return Loss
14.4 dB @ 1575 MHz
Reverse Isolation
28.7 dB @ 1575 MHz
See noise figure plots an tabular data.
These values do NOT extract PCB
losses, etc. resulting from FR4 board
and passives used on PCB - these
results are at input SMA connector.
Two tones, 1574 & 1575 MHz,
-24 dBm each tone.
See Figure 13.
Bill of Material
T = 25 °C, network analyzer source power = -25 dBm
Table 2
Bill of Material
Reference
Designator
Value
Manufacturer
Case
Size
Function
C1
47 pF
Various
0402
DC blocking, input. Also, using cap above selfresonance makes it slightly inductive, slightly
improving input match.
C2
2.2 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
15 pF
Various
0402
Decoupling (RF Short)
C5
2.2 Pf
Various
0402
Decoupling (RF Short). Also has influence on
output match and stability.
C6
0.1 µF
Various
0402
Decoupling, low frequency.
L1
10 nH
Murata LQG15HN
series low cost
inductor
0402
RF choke at input
L2
4.3 nH
Murata LQG15HN
series inductor
0402
RF choke + impedance match at output
Application Note
6
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraTable 2
Bill of Material (cont’d)
Reference
Designator
Value
Manufacturer
Case
Size
Function
R1
10 Ω
Various
0402
Stability improvement
R2
56 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 Ultra-Low Noise RF Transistor
J1, J2
-
Johnson 142-0701841
-
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
7
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraSchematic Diagram for 1575 MHz GPS LNA
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Application Note
8
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraNoise Figure, Plot. Center of Plot (x-axis) is 1575 MHz.
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Figure 5
Noise Figure
Application Note
9
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraNoise Figure, Tabular Data
From Rhode & Schwarz FSEK3 + FSEM30
System Preamplifier = MITEQ SMC-02
Table 3
Noise Figure
Frequency
Noise Figure
1495 MHz
0.70 dB
1515 MHz
0.71 dB
1535 MHz
0.71 dB
1555 MHz
0.69 dB
1575 MHz
0.67 dB
1595 MHz
0.70 dB
1615 MHz
0.70 dB
1635 MHz
0.70 dB
1655 MHz
0.69 dB
Application Note
10
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraScanned Image of PC Board
Figure 6
Image of PC Board
Application Note
11
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraScanned Image of PC Board, Close-In Shot
Figure 7
Image of PC Board, Close-In Shot
Application Note
12
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraPower Sweep at 1575 MHz (CW)
Source Power (Input) swept from -35 to -7 dBm
Input P1dB ≅ -18.0 dBm
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Figure 8
Plot of Power Sweep (1575 MHz)
Application Note
13
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraInput Return Loss, Log Mag
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Figure 9
Plot of Input Return Loss
Application Note
14
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraForward Gain, wide Sweep
(5 MHz - 6 GHz)
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Figure 10
Plot of Forward Gain
Application Note
15
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraReverse Isolation
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Figure 11
Plot of Reverse Isolation
Application Note
16
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraOutput Return Loss, Log Mag
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Figure 12
Plot of Output Return Loss
Application Note
17
Rev. 1.3, 2007-11-16
Application Note No. 117
Low Noise Amplifier (LNA) for 1575 MHz (GPS) Applications using the UltraLNA response to two-tone test
Input Stimulus for Amplifier Two-Tone Test
f1 = 1574 MHz, f2 = 1575 MHz, -24 dBm each tone
Input IP3 = -24 + (44.6 / 2) = -1.7 dBm
Output IP3 = -1.7 dBm + 19.8 dB gain = +18.1 dBm
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Figure 13
Tow-Tone Test (LNA Response)
Application Note
18
Rev. 1.3, 2007-11-16