Download BDTIC www.BDTIC.com/infineon Application Note No. 067

A pp li c at i on N ot e , R ev . 2. 0 , D ec . 2 00 7
A p p li c a t i o n N o t e N o . 0 6 7
G e n e r a l P ur p o s e W i de B an d D r i v er A m p l i f i e r
u s i n g B G A 61 4
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 2007-01-04
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.
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Application Note No. 067
Application Note No. 067
Revision History: 2007-01-04, Rev. 2.0
Previous Version: 2000-02-03
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
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Rev. 2.0, 2007-01-04
Application Note No. 067
General Purpose Wide Band Driver Amplifier using BGA614
1
General Purpose Wide Band Driver Amplifier using BGA614
Features
Easy to use, versatile, cascadable 50 Ω gain block - no external
RF matching required
• Unconditionally stable
• Compression Point P1dB: +12 dBm
• Exceptional noise figure for a low-cost, matched, broadband
device: less than 2.4 dB at 2 GHz
• 70 GHz fT SiGe technology
Applications
• RF amplifier for GSM, PCS, CDMA and UMTS basestations
• Broadband amplifier for SAT-TV, CATV and LNBs
•
3
4
2
1
BDTIC
In, 1
4, GND
GND, 2
3, Out
Top View
AN067_Pin_Cconnection.vsd
Figure 1
PIN configuration
1.1
Introduction
Infineon Technologies’ BGA614 is a matched, general purpose broadband MMIC amplifier in a Darlington
configuration. It is implemented in Infineon’s high fT, low noise B7HF Silicon Germanium technology.
The device’s 3 dB bandwidth covers DC up to 2.7 GHz with a typical gain of 18.5 dB at 1 GHz. The BGA614 is
matched to 50 Ω and is unconditionally stable over the entire frequency range. At a device current of 40 mA the
MMIC has an output 1 dB compression point of +12 dBm. At this same DC operating point, the noise figure is only
2.3 dB at 2 GHz - a value previously unheard of in a low-cost, 50 Ω matched gain block. This exceptional
performance, enabled by Infineon’s 70 GHz B7HF Silicon Germanium process, combined with reduced external
component count and ease of use make BGA614 an ideal choice for a wide variety of RF applications up to
2.5 GHz. The BGA614’s simplicity, flexibility and ease of use streamlines the wireless design process and allows
for shorter design cycles and fast to time-to-market in today’s fast-paced, competitive business environment.
Application Note
4
www.BDTIC.com/infineon
Rev. 2.0, 2007-01-04
Application Note No. 067
General Purpose Wide Band Driver Amplifier using BGA614
Out
In
BDTIC
GND
AN067_equivalent_circuit.vsd
Figure 2
Equivalent Circuit of BGA614
C1
100pF
In
1
4
Q1
BGA614
C2
100pF
2
Out
3
L1
47nH
Vcc
R1
62Ω
C3
100pF
AN067_schematic.vsd
Figure 3
Schematic Diagram
Table 1
Bill of Materials
Name
Value
Unit
Size
Manufacturer
Function
C1
100
pF
0402
Various
DC block
C2
100
pF
0402
Various
DC block
C3
100
pF
0402
Various
RF bypass
L1
47
nH
0402
Toko LL 1005-FH
RF block
R1
62
Ω
0402
Various
Biasing
IC1
BGA614
SOT343
Infineon Technologies
SiGe MMIC
Application Note
5
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Rev. 2.0, 2007-01-04
Application Note No. 067
General Purpose Wide Band Driver Amplifier using BGA614
0.2 mm FR4
35 µm Cu
35 µm Cu
for mechanical
rigidity of PCB
0.8 mm FR4
35 µm Cu
AN067_PCB_cross_section.vsd
Figure 4
PCB Cross Section
BDTIC
Table 2
Performance Overview
Parameter
Value
1.7 GHz
1.95 GHz
2.2 GHz
Supply voltage VCC
5V
5V
5V
Supply current ID
41.2 mA
41.2 mA
41.2 mA
Gain
17.0 dB
16.5 dB
15.9 dB
Noise figure
2.38 dB
2.35 dB
2.32 dB
Input return loss
15.5 dB
14.5 dB
13.7 dB
Output return loss
17.7 dB
16.8 dB
16.0 dB
Reverse Isolation
21.1 dB
20.9 dB
20.6 dB
Output P1dB
12.6 dBm
12.2 dBm
12.6 dBm
1)
23.6 dBm
21.0 dBm
20.8 dBm
Output IP3
1) ∆f = 1 MHz; -20 dBm per tone
1.2
Circuit Design
This application note describes the design of a general purpose broadband driver amplifier for the frequency band
between 1.7 GHz and 2.2 GHz using the BGA614. This band covers the Tx as well as Rx frequencies of various
standards from GSM1800 or DCS1800, North America PCS band, up to W-CDMA.
Implementing an amplifier circuit using BGA614 is a simple, straightforward task. As both input and output are
already matched to 50 Ω and BGA614 is an unconditionally stable device, there is no need to work on the RF
portion of the amplifier design, leaving only DC biasing issues to contend with. The broadband 50 Ω match also
eases and speeds integration of the MMIC with any external filters used.
Figure 5 shows the component placement on the application PCB. There are only five external components
necessary for the complete amplifier circuit. The low external parts count simplifies manufacturing issues and
reduces required PCB area and associated costs.
Application Note
6
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Rev. 2.0, 2007-01-04
Application Note No. 067
General Purpose Wide Band Driver Amplifier using BGA614
In
1
C1
4
5 mm
Q1
2
3
C2
Out
L1
NA
C4
BDTIC
R1
7 mm
Vcc
AN067_PCB_component_placement.vsd
Figure 5
PCB: Component Placement
The BGA614 is biased via its RF output pin (Pin 3). Figure 6 shows the dependence of the device current on the
supply voltage for different values of the bias resistor R1. R1 stabilizes the supply current by using voltage
feedback. In principle it is possible to bias BGA614 without an additional resistor. However, omitting R1 will lead
to increased unit-to-unit variation in operating current due to the usual variation in the DC Beta (hFE) of the internal
transistor cells. It is therefore recommended that R1 be used in all cases.
80
0Ω
16Ω
27Ω
70
47Ω
60
ID [mA]
50
68Ω
40
30
100Ω
20
150Ω
10
0
0
1
2
3
4
5
6
Vcc [V]
AN067_ID(VDD).vsd
Figure 6
Device Current vs. Supply Voltage, Parameter is R1
The inductor L1 in series with resistor R1 is necessary for RF blocking. C4 serves as a RF bypass at the voltage
supply.
The capacitors C1 and C2 are DC blocks as there is DC voltage present on Pin 1 as well as on Pin 3. These
capacitors are needed only if there is no DC open circuit on the input and output of the amplifier. For example, if
Application Note
7
www.BDTIC.com/infineon
Rev. 2.0, 2007-01-04
Application Note No. 067
Measurement Results
a filter that presents a DC open circuit is used ahead of or after the BGA614, the corresponding DC blocking
capacitor may be omitted.
1.3
Remarks
BGA614 is only one member of Infineon Technologies’ broadband Darlingtion MMIC amplifier family. The
complete family consists of BGA612, BGA614 and BGA616 to cover a wide range to typical supply currents.
BGA612 is designed for a typical supply current of 20 mA, BGA614 for 40 mA and the BGA616 for 60 mA.
The BGA614 application PCB can be used to evaluate BGA612 and BGA616 as well. It is only necessary to
change the value of R1 to adjust the devices’ supply current accordingly. Typical values of R1 are 135 Ω at
VCC = 5 V for BGA612 and 33 Ω at VCC = 6 V for BGA616.
For further and more detailed dependencies of the devices’ supply currents please refer to the appropriate data
sheets where graphs like the one in Figure 6 can be found for BGA612 and BGA616.
2
BDTIC
Measurement Results
18
Gain [dB]
17
16
15
14
13
12
1,7
1,8
1,9
2
2,1
2,2
Frequency [GHz]
AN067_Gain(f).vsd
Figure 7
Gain
Application Note
8
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Rev. 2.0, 2007-01-04
Application Note No. 067
Measurement Results
Return Loss [dB]
-10
-12
-14
s11
-16
s22
-18
-20
BDTIC
1,7
1,8
1,9
2
Frequency [GHz]
Figure 8
2,1
2,2
A N067_Return_Loss(f).vsd
Matching
Noise Figure [dB]
3,6
3,2
2,8
2,4
2
1,6
1,7
1,8
1,9
2
2,1
2,2
Frequency [GHz]
AN067_Noise_Figure(f).vsd
Figure 9
Noise Figure
Application Note
9
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Rev. 2.0, 2007-01-04
Application Note No. 067
Measurement Results
Reverse Isolation [dB]
-15
-17
-19
-21
-23
-25
BDTIC
1,7
1,8
1,9
2
2,1
2,2
Frequeny [GHz]
AN067_Reverse_Isolation(f).vsd
Figure 10
Reverse Isolation
1,6
1,4
K, B1
1,2
K
1
0,8
0,6
B1
0,4
0,2
0
1
2
3
4
5
6
Frequency [GHz]
A N067_K_B1(f).vsd
Figure 11
Stability Factor
Application Note
10
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Rev. 2.0, 2007-01-04
Application Note No. 067
15
22
10
20
5
18
Gain
0
16
-5
14
-10
Gain [dB]
Pout [dBm]
Measurement Results
12
Pout
BDTIC
-15
10
-30
-25
-20
-15
-10
-5
Pin [dBm]
Figure 12
0
AN067_Pout(Pin).vsd
Gain Compression
20
Gain [dB]
18
16
14
12
10
8
0
1
2
3
4
5
6
Frequency [GHz]
AN067_wide_span_Gain(f).vsd
Figure 13
Gain, wide span
Application Note
11
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Rev. 2.0, 2007-01-04
Application Note No. 067
Measurement Results
Return Loss [dB]
0
-5
-10
s11
-15
s22
-20
-25
BDTIC
0
1
2
3
4
5
6
Frequency [GHz]
AN067_wide_span_Return_loss(f).vsd
Figure 14
Matching, wide span
Application Note
12
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Rev. 2.0, 2007-01-04