Application Notes

AN11525
BGU6009/N2 GNSS LNA evaluation board
Rev. 1 — 23 April 2014
Application note
Document information
Info
Content
Keywords
BGU6009/N2, GNSS, LNA
Abstract
This document explains the BGU6009/N2 GNSS LNA evaluation board
Ordering info
Board-number: OM7883
12NC: 9340 685 65598
Contact information
For more information, please visit: http://www.nxp.com
AN11525
NXP Semiconductors
BGU6009/N2 GNSS LNA EVB
Revision history
Rev
Date
Description
1
First publication
20140423
Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
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1. Introduction
NXP Semiconductors’ BGU6009/N2 Global Navigation Satellite System (GNSS) LNA
Evaluation Boards is designed to evaluate the performance of the GNSS LNA using:
•
NXP Semiconductors’ BGU6009/N2 GNSS Low Noise Amplifier
•
A matching inductor
•
A decoupling capacitor
NXP Semiconductors’ BGU6009/N2 is a low-noise amplifier for GNSS receiver
applications in a plastic, leadless 6 pin, extremely thin small outline SOT1230 at 1.1 x 0.9
x 0.47 mm, 0.4mm pitch. The BGU6009/N2 features gain of 17 dB and a noise figure of
0.92 dB at a current consumption of 5.1 mA. Its superior linearity performance removes
interference and noise from co-habitation cellular transmitters, while retaining sensitivity.
2
The LNA components occupy a total area of approximately 4 mm .
In this document, the application diagram, board layout, bill of materials, and typical
results are given, as well as some explanations on GNSS related performance
parameters like out-of-band input third-order intercept point O_IIP3, gain compression
under jamming and noise under jamming.
Fig 1.
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BGU6009/N2 GNSS LNA evaluation board
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2. General description
Modern cellular phones have multiple radio systems, so problems like co-habitation are
quite common. A GNSS receiver implemented in a mobile phone requires the following
factors to be taken into account.
All the different transmit signals that are active in smart phones and tablets can cause
problems like inter-modulation and compression.
Since the GNSS receiver needs to receive signals with an average power level of -130
dBm, sensitivity is very important. Currently there are several GNSS chipsets on the
market that can be implemented in cell phones, tablets etc. Although many of these
GNSS ICs do have integrated LNA front ends, the noise performance, and as a result the
system sensitivity, is not always adequate. The GNSS receiver sensitivity is a measure
how accurate the coordinates are calculated. The GNSS signal reception can be
improved by a so called GNSS LNA, which improves the sensitivity by amplifying the
wanted GNSS signal with a low-noise amplifier.
3. BGU6009/N2 GNSS LNA evaluation board
The BGU6009/N2LNA evaluation board simplifies the RF evaluation of the BGU6009/N2
GNSS LNA applied in a GNSS front-end, often used in mobile cell phones. The
evaluation board enables testing of the device RF performance and requires no
additional support circuitry. The board is fully assembled with the BGU6009/N2, including
the input series inductor and decoupling capacitor. The board is supplied with two SMA
connectors for input and output connection to RF test equipment. The BGU6009/N2 can
operate from a 1.5 V to 3.1 V single supply and consumes typical 5.1 mA.
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3.1 Application Circuit
The circuit diagram of the evaluation board is shown in Fig 2. With jumper JU1 the
enable input can be connected either to Vcc or GND.
BGU6009/N2
GNSS LNA
EVB
X3
GND
Ven
Vcc
X4
JU1
C1
6
RF in
2
L1
5
BGU6009/N2
4
X1
3
RF out
X2
1
Fig 2.
Circuit diagram of the BGU6009/N2 LNA evaluation board
3.2 PCB Layout
A good PCB layout is an essential part of an RF circuit design. The LNA evaluation board
of the BGU6009/N2 can serve as a guideline for laying out a board using the
BGU6009/N2. Use controlled impedance lines for all high frequency inputs and outputs.
Bypass Vcc with decoupling capacitors, preferably located as close as possible to the
device. For long bias lines it may be necessary to add decoupling capacitors along the
line further away from the device. Proper grounding of the GND pins is also essential for
good RF performance. Either connect the GND pins directly to the ground plane or
through vias, or do both, which is recommended. The material that has been used for the
evaluation board is FR4 using the stack shown in Fig 4.
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Fig 3.
Printed-Circuit Board layout of the BGU6009/N2 LNA evaluation board
20um Cu
0.2mm FR4 critical
20um Cu
0.8mm FR4 only for
mechanical rigidity of PCB
20um Cu
(1) Material supplier is ISOLA DURAVER; εr = 4.6-4.9: Tδ = 0.02
Fig 4.
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Stack of the PCB material
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4. Bill of materials
Table 1.
BOM of the BGU6009/N2 GNSS LNA evaluation board
Designator Description
Footprint
Value
Supplier Name/type
Comment
F
SOT1230.
BGU6009/N2
1.1x0.9x0.47mm,
NXP
0.4mm pitch
PCB
20x35mm
BGU6009/N2 GNSS LNA EV Kit
C1
Capacitor
0402
1nF
Murata GRM1555
Decoupling
L1
Inductor
0402
6.8nH
Murata LQW15
Input matching
X1, X2
SMA RD
connector
-
-
Johnson, End launch SMA
RF input/ RF output
X3
DC header
-
-
Molex, PCB header, Right Angle, 1 Bias connector
row, 3 way 90121-0763
X4
JUMPER
-
-
Molex, PCB header, Vertical, 1
row, 3 way 90120-0763
142-0701-841
Stage
JU1
Connect Ven to Vcc
or separate Ven
voltage
JUMPER
4.1 BGU6009/N2
NXP Semiconductors’ BGU6009/N2 GNSS low noise amplifier is designed for the GNSS
frequency band. The integrated biasing circuit is temperature stabilized, which keeps the
current constant over temperature. It also enables the superior linearity performance of
the BGU6009/N2. The BGU6009/N2 is also equipped with an enable function that allows
it to be controlled via a logic signal. In disabled mode it consumes less than1 μA.
The output of the BGU6009/N2 is internally matched for 1575.42 MHz whereas only one
series inductor at the input is needed to achieve the best RF performance. Both the input
and output are AC coupled via an integrated capacitor.
It requires only two external components to build a GNSS LNA having the following
advantages:
•
Low noise
•
System optimized gain
•
High linearity under jamming
•
1.1 x 0.9 x 0.47, 0.4mm pitch: SOT1230
•
Low current consumption
•
Short power settling time
4.2 Series inductor
The evaluation board is supplied with Murata LQW15 series inductor of 6.8 nH. This is a
wire wound type of inductor with high quality factor (Q) and low series resistance (Rs).
This type of inductor is recommended in order to achieve the best noise performance.
High Q inductors from other suppliers can be used. If it is decided to use other low cost
inductors with lower Q and higher Rs the noise performance will degrade.
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5. Required Equipment
In order to measure the evaluation board the following is necessary:

DC Power Supply op to 30 mA at 1.5 V to 3.1 V

Two RF signal generators capable of generating RF signals at the operating
frequency of 1575.42 MHz, as well as the jammer frequencies 1713.42 MHz and
1851.42 MHz

An RF spectrum analyzer that covers at least the operating frequency of
1575.42 MHz as well as a few of the harmonics. Up to 6 GHz should be
sufficient.
“Optional” a version with the capability of measuring noise figure is convenient

Amp meter to measure the supply current (optional)

A network analyzer for measuring gain, return loss and reverse isolation

Noise figure analyzer and noise source

Directional coupler

Proper RF cables
6. Connections and setup
The BGU6009/N2 GNSS LNA evaluation board is fully assembled and tested. Please
follow the steps below for a step-by-step guide to operate the LNA evaluation board and
testing the device functions.
1. Connect the DC power supply to the Vcc and GND terminals. Set the power supply to
the desired supply voltage, between 1.5 V and 3.1 V, but never exceed 3.1 V as it
might damage the BGU6009/N2.
2. Jumper JU1 is connected between the Vcc terminal of the evaluation board and the
Ven pin of the BGU6009/N2.
3. Connect the RF signal generator and the spectrum analyzer to the RF input and the
RF output of the evaluation board, respectively. Do not turn on the RF output of the
signal generator yet, set it to -45 dBm output power at 1575.42 MHz, set the
spectrum analyzer at 1575.42 MHz center frequency and a reference level of 0 dBm.
4. Turn on the DC power supply and it should read approximately 5.1 mA.
5. Enable the RF output of the generator: The spectrum analyzer displays a tone
around –28 dBm at 1575.42 MHz.
6. Instead of using a signal generator and spectrum analyzer one can also use a
network analyzer in order to measure gain as well as in- and output return loss.
7. For noise figure evaluation, either a noise figure analyzer or a spectrum analyzer with
noise option can be used. The use of a 5 dB noise source, like the Agilent 364B is
recommended. When measuring the noise figure of the evaluation board, any kind of
adaptors, cables etc between the noise source and the evaluation board should be
minimized, since this affects the noise figure.
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Fig 5.
Evaluation board including its connections
7. Typical Board Performance
Measurements have been carried out using the setup as discussed in Chapter Error!
Reference source not found..
7.1 S-Parameters
S-Parameters of the DUT are measured between port RFin and RFout of the EVB
between the frequencies 500 MHz and 3 GHz, with input power of -45dBm at room
o
temperature (Tamb=25 C).
A typical result the S-parameters as a function of frequency and supply voltage are given
in the following figures
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20
0
18
-5
16
-10
14
-15
-20
12
Vcc = 1.5 V
Gp
10
(dB)
Vcc = 1.8 V
Vcc = 2.85 V
8
Vcc = 3.1 V
6
2
-45
1000
1500 2000
f (MHz)
2500
-50
3000
Vcc = 2.85 V
Vcc = 3.1 V
-35
-40
500
Vcc = 1.8 V
-30
4
0
Vcc = 1.5 V
ISL
-25
(dB)
500
Pi = -45 dBm; Tamb = 25 °C
Fig 6.
Fig 7.
2500
3000
S12 (Isolation) as a function of frequency;
typical values
0
0
-2
-2
-4
-4
-6
-6
-8
-8
Vcc = 1.5 V
RLin
-10
(dB)
Vcc = 1.8 V
-16
-18
-18
1000
1500 2000
f (MHz)
2500
Vcc = 2.85 V
Vcc = 3.1 V
-14
-16
500
Vcc = 1.8 V
-12
Vcc = 3.1 V
-14
Vcc = 1.5 V
RLout
-10
(dB)
Vcc = 2.85 V
-12
-20
3000
Pi = -45 dBm; Tamb = 25 °C
Fig 8.
1500 2000
f (MHz)
Pi = -45 dBm; Tamb = 25 °C
S21 (Power gain) as a function of frequency;
typical values
-20
1000
500
1000 1500 2000 2500 3000
f (MHz)
Pi = -45 dBm; Tamb = 25 °C
S11 (Input return loss) as a function of
frequency; typical values
Fig 9.
S22 (Output return loss) as a function of
frequency; typical values
7.2 Noise figure
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The Noise Figure of the DUT is measured between port RFin and RFout of the EVB
between the frequencies 1500 MHz and 1650 MHz and at room temperature (Tamb=25
o
C).
A typical result of Noise figure as a function of frequency and supply voltage is given
below.
1.2
1.1
1
0.9
NF
(dB)
Vcc = 1.5 V
Vcc = 1.8 V
0.8
Vcc = 2.85 V
Vcc = 3.1 V
0.7
0.6
0.5
1500 1525 1550 1575 1600 1625 1650
f (MHz)
Pi = -45 dBm; Tamb = 25 °C
Fig 10. Noise figure as a function of frequency; typical values
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8. Typical LNA evaluation board results
Table 2.
Typical results measured on the evaluation boards
Operating Frequency is f = 1575.42 MHz unless otherwise specified; Temp = 25 °C
Parameter
Symbol
LNA
LNA
LNA
EVB
EVB
EVB
LNA
EVB
Unit
Remarks
Supply Voltage
VCC
1.5
1.8
2.85
3.1
V
Supply Current
ICC
5.0
5.1
5.5
5.5
mA
Noise Figure
NF
0.95
0.95
1.00
1.00
dB
Power Gain
Gp
17
17
17.5
17.5
dB
Input Return Loss
RLin
12
12
13
13
dB
Output Return Loss
RLout
11
11
11
11
dB
Reverse Isolation
ISOrev
25
25
25
25
dB
Input 1dB Gain Compression
Pi1dB
-7
-7
-4
-4
dBm
Output 1dB Gain Compression
Po1dB
9
9
12.5
12.5
dBm
Input third order intercept point
IIP3
4
5
7
8
dBm
[2]
Output third order intercept point
OIP3
21
22
24.5
25.5
dBm
[2]
Ton
<2
<2
<2
<2
µs
Toff
<1
<1
<1
<1
µs
Power settling time
[1]
[1]
The noise figure and gain figures are measured at the SMA connectors of the evaluation board. The losses of the connectors and the
PCB of approximately 0.05 dB are not subtracted. Measured at Tanb = 25 oC.
[2]
Out of band IP3, jammers at f1=f+138MHz and f2=f+276MHz, where f=1575.42MHz. Pin(f1)=-20dBm, Pin(f2)=-65dBm
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9. Legal information
9.1 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences
of use of such information.
9.2 Disclaimers
Limited warranty and liability — Information in this document is believed to
be accurate and reliable. However, NXP Semiconductors does not give any
representations or warranties, expressed or implied, as to the accuracy or
completeness of such information and shall have no liability for the
consequences of use of such information. NXP Semiconductors takes no
responsibility for the content in this document if provided by an information
source outside of NXP Semiconductors.
In no event shall NXP Semiconductors be liable for any indirect, incidental,
punitive, special or consequential damages (including - without limitation lost profits, lost savings, business interruption, costs related to the removal
or replacement of any products or rework charges) whether or not such
damages are based on tort (including negligence), warranty, breach of
contract or any other legal theory.
Notwithstanding any damages that customer might incur for any reason
whatsoever, NXP Semiconductors’ aggregate and cumulative liability
towards customer for the products described herein shall be limited in
accordance with the Terms and conditions of commercial sale of NXP
Semiconductors.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in life support, life-critical or
safety-critical systems or equipment, nor in applications where failure or
malfunction of an NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
damage. NXP Semiconductors and its suppliers accept no liability for
inclusion and/or use of NXP Semiconductors products in such equipment or
applications and therefore such inclusion and/or use is at the customer’s
own risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
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Customers are responsible for the design and operation of their applications
and products using NXP Semiconductors products, and NXP
Semiconductors accepts no liability for any assistance with applications or
customer product design. It is customer’s sole responsibility to determine
whether the NXP Semiconductors product is suitable and fit for the
customer’s applications and products planned, as well as for the planned
application and use of customer’s third party customer(s). Customers should
provide appropriate design and operating safeguards to minimize the risks
associated with their applications and products.
NXP Semiconductors does not accept any liability related to any default,
damage, costs or problem which is based on any weakness or default in the
customer’s applications or products, or the application or use by customer’s
third party customer(s). Customer is responsible for doing all necessary
testing for the customer’s applications and products using NXP
Semiconductors products in order to avoid a default of the applications and
the products or of the application or use by customer’s third party
customer(s). NXP does not accept any liability in this respect.
Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from national authorities.
Evaluation products — This product is provided on an “as is” and “with all
faults” basis for evaluation purposes only. NXP Semiconductors, its affiliates
and their suppliers expressly disclaim all warranties, whether express,
implied or statutory, including but not limited to the implied warranties of noninfringement, merchantability and fitness for a particular purpose. The entire
risk as to the quality, or arising out of the use or performance, of this product
remains with customer.
In no event shall NXP Semiconductors, its affiliates or their suppliers be
liable to customer for any special, indirect, consequential, punitive or
incidental damages (including without limitation damages for loss of
business, business interruption, loss of use, loss of data or information, and
the like) arising out the use of or inability to use the product, whether or not
based on tort (including negligence), strict liability, breach of contract, breach
of warranty or any other theory, even if advised of the possibility of such
damages.
Notwithstanding any damages that customer might incur for any reason
whatsoever (including without limitation, all damages referenced above and
all direct or general damages), the entire liability of NXP Semiconductors, its
affiliates and their suppliers and customer’s exclusive remedy for all of the
foregoing shall be limited to actual damages incurred by customer based on
reasonable reliance up to the greater of the amount actually paid by
customer for the product or five dollars (US$5.00). The foregoing limitations,
exclusions and disclaimers shall apply to the maximum extent permitted by
applicable law, even if any remedy fails of its essential purpose.
9.3 Trademarks
Notice: All referenced brands, product names, service names and
trademarks are property of their respective owners.
All information provided in this document is subject to legal disclaimers.
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10. List of figures
Fig 1.
Fig 2.
Fig 3.
Fig 4.
Fig 5.
Fig 6.
Fig 7.
Fig 8.
Fig 9.
Fig 10.
BGU6009/N2 GNSS LNA evaluation board ...... 3
Circuit diagram of the BGU6009/N2 LNA
evaluation board ............................................... 5
Printed-Circuit Board layout of the BGU6009/N2
LNA evaluation board ....................................... 6
Stack of the PCB material ................................. 6
Evaluation board including its connections ....... 9
S21 (Power gain) as a function of frequency;
typical values .................................................. 10
S12 (Isolation) as a function of frequency; typical
values ............................................................. 10
S11 (Input return loss) as a function of
frequency; typical values ................................. 10
S22 (Output return loss) as a function of
frequency; typical values ................................. 10
Noise figure as a function of frequency; typical
values ............................................................. 11
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11. List of tables
Table 1.
Table 2.
BOM of the BGU6009/N2 GNSS LNA evaluation
board ................................................................. 7
Typical results measured on the evaluation
boards ............................................................. 12
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12. Contents
1.
2.
3.
3.1
3.2
4.
4.1
4.2
5.
6.
7.
7.1
7.2
8.
9.
9.1
9.2
9.3
10.
11.
12.
Introduction ......................................................... 3
General description............................................. 4
BGU6009/N2 GNSS LNA evaluation board ........ 4
Application Circuit .............................................. 5
PCB Layout ........................................................ 5
Bill of materials.................................................... 7
BGU6009/N2 ...................................................... 7
Series inductor ................................................... 7
Required Equipment ........................................... 8
Connections and setup ....................................... 8
Typical Board Performance ................................ 9
S-Parameters ..................................................... 9
Noise figure ...................................................... 10
Typical LNA evaluation board results ............. 12
Legal information .............................................. 13
Definitions ........................................................ 13
Disclaimers....................................................... 13
Trademarks ...................................................... 13
List of figures..................................................... 14
List of tables ...................................................... 15
Contents ............................................................. 16
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in the section 'Legal information'.
© NXP B.V. 2014.
All rights reserved.
For more information, visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
Date of release: 23 April 2014
Document identifier: AN11525