AN11338 BGU8011 GNSS front end evaluation board

AN11338
BGU8011 GNSS front end evaluation board
Rev. 1 — 29 May 2013
Application note
Document information
Info
Content
Keywords
BGU8011, GNSS, FE, LNA
Abstract
This document explains the BGU8011 GNSS FE evaluation board
Ordering info
Board-number: OM7842
12NC: 9340 679 11598
Contact information
For more information, please visit: http://www.nxp.com
AN11338
NXP Semiconductors
BGU8011 GNSS FE EVB
Revision history
Rev
Date
Description
1
First publication
20130529
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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BGU8011 GNSS FE EVB
1. Introduction
NXP Semiconductors’ BGU8011 Global Navigation Satellite System (GNSS) Front end
Evaluation Board (BGU8011 GNSS FE EVB) is designed to evaluate the performance of
the GNSS front end using:

NXP Semiconductors’ BGU8011 GNSS Low Noise Amplifier

A matching inductor

A decoupling capacitor

Two identical GNSS band-pass filters
NXP Semiconductors’ BGU8011 is a low noise amplifier for GNSS receiver applications
3
in a plastic, leadless 6 pin, extremely thin small outline SOT1230 at 1.1 x 0.9 x 0.5mm ,
0.4mm pitch. The BGU8011 features gain of 16.3 dB and a noise figure of 0.65 dB at a
current consumption of 4.4 mA. Its superior linearity performance removes interference
and noise from co-habitation cellular transmitters, while retaining sensitivity. The LNA
2
components occupy a total area of approximately 8.4 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.
AN11338
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BGU8011 GNSS front end evaluation board
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BGU8011 GNSS FE EVB
2. General description
Modern smart 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 intermodulation and compression.
Since the GNSS receiver needs to receive signals with an average power level of -130
dBm, sensitivity is very important. Many of the available GNSS ICs have integrated LNA
front ends. The noise performance of these integrated LNA front ends, and as a result
the system sensitivity, is not always adequate. The GNSS receiver sensitivity is a
measure for how accurate the coordinates are calculated. The GNSS signal reception
can be improved by a so called GNSS front end, which improves the sensitivity by
filtering out the unwanted jamming signals and by amplifying the wanted GNSS signal
with a low noise amplifier.
The pre-filters and post filters are needed to improve the overall linearity of the system as
well as to avoid overdriving the integrated LNA stage of the GNSS receiver.
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3. BGU8011 GNSS front end evaluation board
The BGU8011 front end evaluation board simplifies the RF evaluation of the BGU8011
GNSS LNA applied in a GNSS front end, that is often used in smart phones. The
evaluation board enables testing of the device RF performance and requires no
additional support circuitry. The board is fully assembled with the BGU8011, including the
input series inductor, decoupling capacitor as well as two SAW filters to optimize the
linearity performance. The board is supplied with two SMA connectors for input and
output connection to RF test equipment. The BGU8011 can operate from a 1.5 V to 3.1 V
single supply and consumes about 4.4 mA.
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.
BGU8011
GNSS FE
EVB
X3
GND
Ven
Vcc
X4
JU1
C1
6
2
RF in
L1
5
BGU8011
SAW
4
X1
RF out
3
SAW
X2
1
Fig 2.
Circuit diagram of the BGU8011 front end evaluation board
3.2 PCB Layout
A good PCB layout is an essential part of an RF circuit design. The front end evaluation
board of the BGU8011 can serve as a guideline for laying out a board using the
BGU8011. Use controlled impedance lines for all high frequency inputs and outputs.
Bypass Vcc with decoupling capacitors, preferably located as close as possible to the
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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 out-of-band rejection of the SAW
filters also depends on the grounding of the filter. The material that has been used for the
evaluation board is FR4 using the stack shown in Fig 4. The input circuit has also SMDpositions for optional input filtering circuits (not used in this version of the FE EVB).
3.3 Board Layout
Fig 3.
AN11338
Application note
Printed-Circuit Board layout of the BGU8011 front end evaluation board
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BGU8011 GNSS FE EVB
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: T
Fig 4.
Stack of the PCB material
4. Bill of materials
Table 1.
BOM of the BGU8011 GNSS front end evaluation board
Designator Description
Footprint
Value
Supplier Name/type
Marking
code: C
BGU8011
1.1 x 0.9 x 0.5
3
mm
NXP
Comment
SOT1230
0.4 mm pitch
PCB
20 x 35 mm
2
BGU8011 GNSS FE EV Kit
C1
Capacitor
0402
1nF
Murata GRM1555
Decoupling
L1
Inductor
0402
5.6nH
Murata LQW15
Input matching
JK
SAW BPF
1.4 x 1.1 x 0.4
EPCOS B8313
[1]
Johnson, End launch SMA
RF input/ RF output
mm
3
X1, X2
SMA RF
connector
-
-
X3
DC header
-
-
Molex, PCB header, Right Angle, 1
row, 3 way 90121-0763
Bias connector
X4
JUMPER
-
-
Molex, PCB header, Vertical, 1 row,
3 way 90120-0763
Connect Ven to Vcc
or separate Ven
voltage
Stage
JU1
[1]
142-0701-841
JUMPER
Similar performance can also be achieved with GNSS SAW filters from other suppliers. See paragraph 4.2
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4.1 BGU8011
By dynamically suppressing strong cellular and WLAN transmit signals, an industry first,
these LNAs offer the best reception of weak GPS signals. Linearity improves with a 10
dB better IP3 under -40 to -20 dBm jamming conditions, while NF remains below 1 dB.
Requiring only two external components, they save up to 50% in PCB size and 10% in
component cost, offering the smallest footprint in the market.
The BGU8011 is a Low Noise Amplifier (LNA) for GNSS receiver applications, available
in a small plastic 6-pin extremely thin leadless package. The BGU8011 requires one
external matching inductor and one external decoupling capacitor. The BGU8011 adapts
itself to the changing environment resulting from co-habitation of different radio systems
in modern cellular handsets. It has been designed for low power consumption and
optimal performance when jamming signals from co-existing cellular transmitters are
present. At low jamming power levels it delivers 16.3 dB gain at a noise figure of 0.65 dB.
During high jamming power levels, resulting for example from a cellular transmit burst, it
temporarily increases its bias current to improve sensitivity.
4.2 Band pass filters
The band-pass filters that are implemented in the GNSS front end evaluation board are
key components regarding the overall system linearity and sensitivity. One of the key
performance indicators of these filters is having very high rejection at the different smart
phone TX frequencies, and simultaneously having low insertion loss in the GNSS passband. The evaluation board is supplied with two EPCOS B8313 SAW-filters (GPS,
COMPASS, Galileo and GLONASS). Alternatives to be considered:
1. Murata SAFA1G57KH0F00
2. Murata SAFA1G57KB0F00 low loss variant
3. Fujitsu FAR-F6KA-1G5754-L4AA
4. Fujitsu FAR-F6KA-1G5754-L4AJ
All these filters can use the same footprint. In order to be able to achieve the rejection
level as indicated in the data sheet of these filters, it is necessary that the filters are
properly grounded. In the layout of the front end evaluation board the suppliers’
recommendations have been followed. See Fig 5, please note that every GND pin has its
own ground-via and there is a ground path between the input and the output.
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Fig 5.
SAW filter footprint
4.3 Series inductor
The evaluation board is supplied with Murata LQW15 series inductor of 5.6nH. 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:

AN11338
Application note
DC Power Supply up 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
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BGU8011 GNSS FE EVB
6. Connections and setup
The BGU8011 GNSS front end evaluation board is fully assembled and tested. Please
follow the steps below for a step-by-step guide to operate the front end evaluation board
and test 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 BGU8011.
2. Jumper JU1 is connected between the Vcc terminal of the evaluation board and the
Ven pin of the BGU8011.
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 -40 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 4.4mA.
5. Enable the RF output of the generator: The spectrum analyzer displays a tone
around –25 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 15 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
avoided, since this affects the noise figure.
Fig 6.
AN11338
Application note
Evaluation board including its connections
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BGU8011 GNSS FE EVB
7. Linearity
At the average power levels of –130 dBm that have to be received by a GNSS receiver,
the system will not have in-band intermodulation problems caused by the GNSS-signal
itself. Strong out-of-band smart phone TX jammers however can cause linearity
problems, and result in third-order intermodulation products in the GNSS frequency
band. In this chapter the effects of these Jammer-signals on the Noise and Gain
performance of the BGU8011 are described. The effect of these Jammers on the In-band
and Out-of-Band Third-Order Intercept points are described in more detail in a separate
User Manual: UM10453: 2-Tone Test BGU7005 and BGU7007 GPS LNA.
7.1 Out-of-band input third-order intercept point
This parameter is being measured by a two-tone measurement where the carriers have
been chosen as L1+138 MHz and L1+276 MHz. Where L1 is the center of the GNSS
band, 1575.42 MHz. So the two carriers are 1713.42 MHz and 1851.42 MHz that can be
seen as two TX jammers in UMTS FDD and GSM1800 cell phone systems.
One third-order product (2f1-f2) generated in the LNA due to amplifier third-order
nonlinearities can fall at the desired 1575.42 MHz frequency as follows:
2f1-f2 = 2(1713.42 MHz)-1851.42 MHz = 1575.42 MHz.
This third-order product can influence the sensitivity of the GNSS receiver drastically. So
this third-order intermodulation product needs to be as low as possible, meaning the outof-band intercept point must be as high as possible.
Fig 7 shows the measurement setup used to measure the out-of-band third order
intercept point. Two RF-generators are used to generate the jammers f 1 and f2. These
two jammers are combined by an RF combiner. A notch filter is used to prevent inserting
an RF signal at the GNSS frequency into the front end caused by intermodulation of the
two generators and RF combiner combination.
BGU7007
BGU8011
GPS FE
GNSS FE
EVB
EVB
X3
X3
GND
GND VVenen Vcc
cc
X4X4
JU1
JU1
RF-generator 2
RF-generator 1
Fig 7.
RF
combiner
GPS
notch
C1C1
65
RF
RFinin
X1
SAW
2
L1L1 5 3
4
BGU7007
BGU8011
SAW
X1
41
12
6 3
SAW RF
RFout
out
SAW
Spectrum
analyzer
X2
X2
Out-of-band input third order intercept point measurement setup
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The input power levels of f1 and f2 that have been used to measure the IM3 levels on the
front end evaluation board were +10 dBm, shown in Fig 8. Fig 9 shows the IM3 level at
the output of the front end, measured at VCC = 2.85 V.
With the levels shown in Fig 8 and Fig 9, the out-of-band input third-order intercept point
can be calculated.
As shown in Fig 8 Pin of both f1 and f2 is +10 dBm.
Left-side OIM3 = -93.7 dBm (see Fig 9)
The gain ( G p ) of the front end is 14.9 dB (the typ. insertion loss of the EPCOS B8313
SAW filters is ~0.8dB).
Fig 8.
Input jammers for IM3 measurements
f1=1713MHz/+10dBm and f2=1851MHz/+10dBm
AN11338
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Fig 9.
FE output IM3 level at 1575 MHz
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7.2 In-band 1dB gain compression due to 787MHz, 850MHz and 1850MHz
jammers
For the measurement described below it is necessary to have clean jammer signals with high RF power in
order to measure these parameters on the actual front end evaluation board. Since these clean signals are
hard to generate, these measurements are performed on a BGU8011 GNSS Low noise amplifier evaluation
board (user manual available: AN11337). With the results of these measurements and the typical rejection
levels of the band-pass filters at the jamming frequencies, the values valid for the front end evaluation board
can be calculated.
As already stated before, signal levels in the GNSS frequency band of -130dBm average
will not cause linearity problems in the GNSS band itself. This of course is also valid for
the 1dB gain compression in-band. The 1dB compression point at 1575.42MHz caused
by smart phone TX jammers however is important.
Measurements have been carried out using the setup shown in Fig 10.
BGU7007
BGU8011
GPS LNA
GNSS LNA
EVB
X3
X3
GND
GND
Ven
en
Vcc
cc
EVB
X4
Jammer signal
JU1
JU1
RF-generator 2
C1
65
RF-generator 1
-20dB
RF
RF in
in
Directional coupler
2
L1
L1
4
53
BGU7007
BGU8011
BGU8006
41
X1
X1
12
63
RF out
out
Spectrum
analyzer
X2
X2
Fig 10. 1dB Gain compression under jamming measurement setup (LNA evaluation board)
The gain was measured between port RFin and RFout of the EVB at the GNSS
frequency, while simultaneously a jammer power signal was swept at 20dB attenuated
input of the directional coupler. Please note that the drive power of the jammer is 20dB
lower at the input of the DUT caused by the directional coupler. Fig 11, Fig 12 and Fig 13
show the gain compression curves with 787MHz, 850MHz and 1850MHz jammers
respectively (taking into account the approx 20 dB attenuation of the directional coupler
and RF-cable from Jammer-Generator to the directional coupler).
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Calculating the power level at the front end gain with 1 dB compression is done as
follows:
At 1 dB gain drop the jammer input power for 850MHz jammer is approx. at -6 dBm (Vcc
= 2.85 V, Fig 11). This is for the LNA only. Using the typical rejection of the SAW filter at
(1)
850 MHz which is 51dB the 1dB compression jammer signal level equals:
-6 + 51 = +45 dBm.
At 1 dB gain drop the jammer input power for 850MHz jammer is approx. at -6 dBm (Vcc
= 2.85 V, Fig 12). This is for the LNA only. Using the typical rejection of the SAW filter at
(2)
850 MHz which is 51dB the 1dB compression jammer signal level equals:
-6 + 51 = +45 dBm.
For 1850 MHz jammer the jammer input power is approx. at -3 dBm (Vcc = 2.85 V, Fig
13). Again this is for the LNA only. Using the typical rejection of the SAW filter at 1850
(3)
MHz which is 43 dB the 1 dB compression jammer signal level equals: -3 + 43 = +40
dBm.
Gain=f(P_Jammer)
Gain=f(P_Jammer)
BGU8011 LNA- & FE-EVB, F_Jammer=787Hz
FE-EVB: Calculated values
BGU8011 LNA- & FE-EVB, F_Jammer=850MHz
FE-EVB: Calculated values
18
18
17
17
16
16
1.50V, LNA-EVB
1.50V, LNA-EVB
15
1.80V, LNA-EVB
2.85V, LNA-EVB
14
3.1V, LNA-EVB
1.50V, FE-EVB
13
Gain [dB]
Gain [dB]
15
1.80V, LNA-EVB
2.85V, LNA-EVB
14
3.1V, LNA-EVB
1.50V, FE-EVB
13
1.80V, FE-EVB
12
2.85V, FE-EVB
3.1V, FE-EVB
11
10
1.80V, FE-EVB
12
2.85V, FE-EVB
3.1V, FE-EVB
11
10
-40
-30
-20
-10
0
10
20
30
40
50
-40
-30
-20
-10
P_Jammer [dBm]
(Pin 1575 MHz = -45 dBm)
AN11338
Application note
10
20
30
40
50
(Pin 1575 MHz = -45 dBm)
Fig 11. Gain versus jammer power at 787 MHz
1.
2.
3.
0
P_Jammer [dBm]
Fig 12. Gain versus jammer power at 850 MHz
Typical rejection at 787MHz from datasheet of EPCOS B8313 SAW filter
Typical rejection at 850MHz from datasheet of EPCOS B8313 SAW filter
Typical rejection at 1850MHz from datasheet of EPCOS B8313 SAW filter
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BGU8011 GNSS FE EVB
Gain=f(P_Jammer)
BGU8011 LNA- & FE-EVB, F_Jammer=1850MHz
FE-EVB: Calculated values
18
17
16
1.50V, LNA-EVB
Gain [dB]
15
1.80V, LNA-EVB
2.85V, LNA-EVB
14
3.1V, LNA-EVB
1.50V, FE-EVB
13
1.80V, FE-EVB
12
2.85V, FE-EVB
3.1V, FE-EVB
11
10
-40
-30
-20
-10
0
10
20
30
40
50
P_Jammer [dBm]
(Pin 1575 MHz = -45 dBm)
Fig 13. Gain versus jammer power at 1850 MHz
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8. Noise figure as function of jammer power at 850MHz
and 1850MHz
For the measurement described below it is necessary to have clean jammer signals with high RF power in
order to measure these parameters on the actual front end evaluation board. Since these clean signals are
hard to generate, these measurements are performed on a BGU8011 GNSS Low noise amplifier evaluation
board (user manual available: AN11230). With the results of these measurements and the typical rejection
levels of the band-pass filters at the jamming frequencies, the values valid for the front end evaluation board
can be calculated.
Noise figure under jamming conditions is a measure of how the LNA behaves when e.g.
a GSM TX interfering signal is at the input of the GNSS antenna. To measure this
behavior the setup shown in Fig 14 is used.
The jammer signal is coupled via a directional coupler to the DUT: this is to avoid the
jammer signal damaging the noise source. The GNSS BPF is needed to avoid driving the
second stage LNA in saturation.
BGU7007
BGU8011
GPS LNA
GNSS LNA
EVB
X3X3
GND
GND VenVen VccVcc
EVB
X4X4
Jammer signal
JU1
JU1
RF-generator
C1C1
56
Noise
Source
-20dB
RF
RF in
in
Directional coupler
2
L1
L1
4
35
BGU7007
BGU8011
14
X1
X1
6 3
RFRF
outout
SAW
2nd stage
LNA
Noise
analyzer
X2
21
X2
Fig 14. Noise under jamming measurement setup (LNA evaluation board)
With the results of these measurements and the specification of the SAW filter, the
jammer power levels that cause noise increase can be calculated.
Calculating the power level at which the front end noise starts to increase is done as
follows:
As can be seen in Fig 15 with a 850 MHz jammer the LNA starts increasing the noise at
Pjam = -25 dBm (Vcc = 2.85 V). For the front end the TX rejection of the first BPF needs
(4)
to be added. For the SAW filter used the rejection at 850 MHz is 51 dB . This means the
noise of the front end will start increasing at an 850 MHz jammer level of Pjam = -25 + 51
= +26 dBm.
For the 1850 MHz jammer the LNA noise starts to increase at Pjam = -30 dBm (Vcc = 2.85
(5)
V, see Fig 16). The rejection of the SAW filter at 1850 MHz is 43 dB . This means the
4.
5.
AN11338
Application note
Rejection at 850MHz from datasheet of EPCOS B8313 SAW filter
Rejection at 1850MHz from datasheet of EPCOS B8313 SAW filter
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noise of the front end will start increasing at an 1850 MHz jammer level of Pjam = -30 +43
= +13 dBm.
NF [dB]=f(P_Jammer)
NF [dB]=f(P_Jammer)
BGU8011 LNA- & FE-EVB, Fjammer=850MHz
BGU8011 LNA- & FE-EVB, Fjammer=1850MHz
FE-EVB: Calculated values
FE-EVB: Calculated values
3.00
3.00
1.5V, LNA-EVB
2.00
1.5V, LNA-Board
2.00
2.85V, LNA-EVB
3.1V, LNA-EVB
1.5V, FE-EVB
1.00
1.8V, LNA-Board
NF [dB]
NF [dB]
1.8V, LNA-EVB
2.85V, LNA-Board
3.1V, LNA-Board
1.5V, FE-Board
1.00
1.8V, FE-EVB
1.8V, FE-Board
2.85V, FE-EVB
2.85V, FE-Board
3.1V, FE-Board
3.1V, FE-EVB
0.00
0.00
-40 -30 -20 -10
0
-40 -30 -20 -10
10 20 30 40 50
Incl. the losses of the connectors and the PCB.
Measured at Tanb = 25 oC.
Fig 15. NF at 1575 MHz versus jammer power at 850
MHz
AN11338
Application note
0
10 20 30 40 50
P_Jammer [dBm]
P_Jammer [dBm]
Incl. the losses of the connectors and the PCB.
Measured at Tanb = 25 oC.
Fig 16. NF at 1575 MHz versus jammer power at 1850
MHz
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BGU8011 GNSS FE EVB
9. TX rejection levels
When measuring the front end evaluation board the input level of the network analyzer
has to be on -45 dBm to avoid activating the adaptive biasing. This low input level results
in a very inaccurate measurement result of the TX rejection. Fig 17 and Fig 18 show the
typical TX rejection levels measured more accurate due to segmented power calibration.
Typical BGU8011 FE-Board, Vcc=2.85V
0
10
0
-10
S21 [dB]
-20
CELL BAND
REJECTION >90dB
PCS BAND
REJECTION >80dB
-30
Return
Loss [dB]
20
S21
S11
S22
-40
-50
-60
-5
-10
-15
-20
-70
-80
-25
-90
-100
5.00E+08
1.00E+09
1.50E+09
Freq [Hz]
2.00E+09
-30
2.50E+09
Fig 17. Typical S-parameter plot at Vcc = 2.85 V
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BGU8011 GNSS FE EVB
BGU8011 FE-Board
40
10
20
5
0
S21 [dB]
0
-20
-40
-5
S11
-10
S22
-60
-15
-20
-80
-100
1.4E+09
S21
-25
1.5E+09
1.6E+09
Freq [Hz]
1.7E+09
-30
1.8E+09
Fig 18. Typical pass band response at Vcc = 2.85 V
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BGU8011 GNSS FE EVB
10. LTE rejection level
The second harmonic of an LTE signal (788MHz) falls into the GNSS band (2x 788MHz
= 1576MHz) and can be responsible for a reduction of the sensitivity of the GNSSsystem. To test the Second Harmonic (H2) –performance, a measurement has been
done.
The measurement setup is given in Fig 19. A notch is used to reduce the second
harmonic caused by the input generator. A 10dB attenuator is used to get a good 50Ω
impedance (some notch filters have an output impedance which is not 50Ω over a wide
frequency range).
BGU7007
BGU8011
GPS LNA
GNSS FE
EVB
X3
X3
GND
Ven
en
Vcc
cc
EVB
X4
Jammer signal
Suppress H2RF-generator
2
JU1
JU1
RF-generator
C1
65
RF-NOTCH-20dB
ATT
Directional coupler 10dB
@1576MHz
RF-generator 1
2
RF
RF in
in
X1
L1
4
L1
53
BGU7007
BGU8011
SAW
41
X1
RF
out
RF out
63
SAW
Spectrum
analyzer
X2
X2
12
F = 788MHz
Improve mismatch RF-Notch-filter
Fig 19. LTE rejection measurement setup (LNA evaluation board)
Table 2 shows an overview of the measured performance (as comparison also the P_H2
results of the BGU8011 LNA-EVB is given; source: AN11288, BGU8011 GNSS LNA
evaluation board).
Table 2.
Measured performance of BGU8011 LNA- and FE EVB’s
Vcc=2.85V, Icc ~4.7mA, Temp = 25 °C
Parameter
Symbol
Pin=0dBm
Pin=+5dBm
Pin=+10dBm
Unit
P_H2 (input referred)
-82
dBm
[1]
P_H2
-102
-92
Remarks
[1]
Fin = 788MHz, Fmeas = 1576MHz.
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BGU8011 GNSS FE EVB
11. Typical front end evaluation board results
Table 3.
Typical results measured on the evaluation boards
Operating Frequency is f = 1575.42 MHz unless otherwise specified; Temp = 25 °C
Parameter
Symbol
FE EVB FE EVB FE EVB
FE EVB
Unit
Supply Voltage
Remarks
VCC
1.5
1.8
2.85
3.1
V
Supply Current
ICC
4.1
4.2
4.4
4.5
mA
Noise Figure
NF
1.6
1.6
1.5
1.5
dB
Power Gain
Gp
14.5
14.7
14.9
15.0
dB
Input Return Loss
RLin
11.8
12.3
12.8
12.9
dB
Output Return Loss
RLout
13.8
13.6
13.5
13.5
dB
Reverse Isolation
ISOrev
29.4
29.4
29.5
29.5
dB
Input 1dB Gain Compression
Pi1dB
-9.6
-7.8
-5.2
-5.0
dBm
Output 1dB Gain Compression
Po1dB
3.8
5.8
8.8
9.0
dBm
Input 1dB Gain Compression
jammer level at 850MHz
Pi1dB850MHz
+40
dBm
[4]
Input 1dB Gain Compression
jammer level at 1850MHz
Pi1dB1850MHz
+45
dBm
[4]
P_H2 (input referred)
P_H2
-82
dBm
[3][4]
Cell band rejection at 850 MHz
relative to 1575.42 MHz
TX_rej850MHz
>90
dBc
[4]
Cell band rejection at 1850 MHz
relative to 1575.42 MHz
TX_rej1850MHz
>80
dBc
[4]
Output third order intermod.
OIM3
-93.7
dBm
[5]
Power settling time
Ton
<2
<2
<2
<2
µs
Toff
<1
<1
<1
<1
µs
[2]
[2]
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 0.1dB are not subtracted. Measured at Tanb = 25 oC.
[3]
Fin = 788MHz, Pin = +10dBm, Fmeas = 1576MHz.
[4]
These parameters are mainly determined by the TX rejection levels of the used BPFs, in this case the EPCOS B8313 SAW filter, but
the performance can also be achieved with the use of GNSS SAW filters from other suppliers that are on the market.
See paragraph 4.2.
[5]
Out of band IM3-component (OIM3) at 1575MHz, jammers at f1=f+138MHz and f2=f+276MHz, where f=1575MHz.
Pin(f1)=Pin(f2)=+10dBm
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12. Legal information
12.1 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.
12.2 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.
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 accepts 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.
Customers are responsible for the design and operation of their applications
and products using NXP Semiconductors products, and NXP
AN11338
Application note
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 competent 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.
12.3 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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BGU8011 GNSS FE EVB
13. List of figures
Fig 1.
Fig 2.
Fig 3.
Fig 4.
Fig 5.
Fig 6.
Fig 7.
Fig 8.
Fig 9.
Fig 10.
Fig 11.
Fig 12.
Fig 13.
Fig 14.
Fig 15.
Fig 16.
Fig 17.
Fig 18.
Fig 19.
BGU8011 GNSS front end evaluation board..... 3
Circuit diagram of the BGU8011 front end
evaluation board ............................................... 5
Printed-Circuit Board layout of the BGU8011
front end evaluation board ................................ 6
Stack of the PCB material ................................. 7
SAW filter footprint ............................................ 9
Evaluation board including its connections ..... 11
Out-of-band input third order intercept point
measurement setup ........................................ 12
Input jammers for IM3 measurements ............ 13
FE output IM3 level at 1575 MHz .................... 13
1dB Gain compression under jamming
measurement setup (LNA evaluation board)... 14
Gain versus jammer power at 787 MHz .......... 15
Gain versus jammer power at 850 MHz .......... 15
Gain versus jammer power at 1850 MHz ........ 16
Noise under jamming measurement setup (LNA
evaluation board) ............................................ 17
NF at 1575 MHz versus jammer power at 850
MHz ................................................................ 18
NF at 1575 MHz versus jammer power at 1850
MHz ................................................................ 18
Typical S-parameter plot at Vcc = 2.85 V........ 19
Typical pass band response at Vcc = 2.85 V .. 20
LTE rejection measurement setup (LNA
evaluation board) ............................................ 21
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14. List of tables
Table 1.
Table 2.
Table 3.
BOM of the BGU8011 GNSS front end
evaluation board ............................................... 7
Measured performance of BGU8011 LNA- and
FE EVB’s......................................................... 21
Typical results measured on the evaluation
boards ............................................................. 22
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BGU8011 GNSS FE EVB
15. Contents
1.
2.
3.
3.1
3.2
3.3
4.
4.1
4.2
4.3
5.
6.
7.
7.1
7.2
8.
9.
10.
11.
12.
12.1
12.2
12.3
13.
14.
15.
Introduction ......................................................... 3
General description ............................................. 4
BGU8011 GNSS front end evaluation board ..... 5
Application Circuit .............................................. 5
PCB Layout ........................................................ 5
Board Layout ...................................................... 6
Bill of materials.................................................... 7
BGU8011 ........................................................... 8
Band pass filters................................................. 8
Series inductor ................................................... 9
Required Equipment ......................................... 10
Connections and setup ..................................... 11
Linearity ............................................................. 12
Out-of-band input third-order intercept point .... 12
In-band 1dB gain compression due to 787MHz,
850MHz and 1850MHz jammers ...................... 14
Noise figure as function of jammer power at
850MHz and 1850MHz ....................................... 17
TX rejection levels ............................................. 19
LTE rejection level............................................. 21
Typical front end evaluation board results ..... 22
Legal information .............................................. 23
Definitions ........................................................ 23
Disclaimers....................................................... 23
Trademarks ...................................................... 23
List of figures..................................................... 24
List of tables ...................................................... 25
Contents ............................................................. 26
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. 2013.
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: 29 May 2013
Document identifier: AN11338