Ublox LEA-M8F Hardware Integration Manual
Text of the manual
u-blox M8 time and frequency reference
GNSS module
Hardware Integration Manual
Abstract
This document describes the hardware features and design-in
aspects for the LEA-M8F time and frequency reference module. This
device incorporates the u-blox M8 concurrent GNSS IC that can
receive GPS, GLONASS, BeiDou and QZSS signals. It provides a low
phase noise 30.72MHz system reference oscillator disciplined by
GNSS, a precise and jitter-free time-pulse and features high
sensitivity signal acquisition and single satellite timing with
automatic hold over during signal outage.
www.u-blox.com
UBX-14000034 - R03
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Document Information
Title
LEA-M8F
Subtitle
u-blox M8 time and frequency reference GNSS module
Document type
Hardware Integration Manual
Document number
UBX-14000034
Revision and Date
R03
19-Aug-2014
Document status
Early Production Information
Document status explanation
Objective Specification
Document contains target values. Revised and supplementary data will be published later.
Advance Information
Document contains data based on early testing. Revised and supplementary data will be published later.
Early Production Information
Document contains data from product verification. Revised and supplementary data may be published later.
Production Information
Document contains the final product specification.
This document applies to the following products:
Product name
Type number
ROM/FLASH version
PCN reference
LEA-M8F
LEA-M8F-0-00
FLASH FW2.20 FTS1.01
N/A
u-blox reserves all rights to this document and the information contained herein. Products, names, logos and designs described herein may in
whole or in part be subject to intellectual property rights. Reproduction, use, modification or disclosure to third parties of this document or
any part thereof without the express permission of u-blox is strictly prohibited.
The information contained herein is provided “as is” and u-blox assumes no liability for the use of the information. No warranty, either
express or implied, is given, including but not limited, with respect to the accuracy, correctness, reliability and fitness for a particular purpose
of the information. This document may be revised by u-blox at any time. For most recent documents, visit www.u-blox.com.
Copyright © 2014, u-blox AG.
u-blox
® is a registered trademark of u-blox Holding AG in the EU and other countries. ARM
® is the registered trademark of ARM Limited in
the EU and other countries.
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Contents
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Contents
Contents .............................................................................................................................. 3
1
Hardware description .................................................................................................. 5
1.1
Overview .............................................................................................................................................. 5
1.2
Architecture .......................................................................................................................................... 6
1.3
Pin description for LEA-M8F designs ..................................................................................................... 7
1.4
Connecting power ................................................................................................................................ 8
1.4.1
VCC .............................................................................................................................................. 8
1.4.2
V_BCKP ......................................................................................................................................... 8
1.4.3
VCC_RF ......................................................................................................................................... 8
1.5
Interfaces .............................................................................................................................................. 8
1.5.1
UART ............................................................................................................................................. 8
1.5.2
USB ............................................................................................................................................... 8
1.5.3
Display Data Channel (DDC) .......................................................................................................... 9
1.5.4
SPI ................................................................................................................................................. 9
1.5.5
DDC interface for External DAC Control ...................................................................................... 10
1.6
I/O and Control Pins............................................................................................................................ 10
1.6.1
RESET_N ...................................................................................................................................... 10
1.6.2
D_SEL .......................................................................................................................................... 10
1.6.3
FREQ_PHASE_IN0 / EXINT0, FREQ_PHASE_IN1 / EXTINT1 ............................................................. 11
1.6.4
REF_FREQ_OUT ........................................................................................................................... 11
1.6.5
TIMEPULSE / TP2 ......................................................................................................................... 11
1.7
Device Configuration .......................................................................................................................... 11
2
Design ......................................................................................................................... 12
2.1
Layout: Footprint and paste mask ....................................................................................................... 12
2.1.1
Placement ................................................................................................................................... 12
2.1.2
Antenna connection and ground plane design ............................................................................ 13
2.1.3
Antenna micro strip connection ................................................................................................... 15
2.2
GNSS Antenna Connection ................................................................................................................. 16
2.2.1
Passive Antenna Connection ....................................................................................................... 16
2.2.2
Active antenna connection .......................................................................................................... 17
3
Migration to u-blox M8 modules .............................................................................. 18
3.1
Software migration ............................................................................................................................. 18
3.2
Hardware migration LEA-6T -> LEA-M8F ............................................................................................ 18
Supply Voltage ................................................................................................................. 19
4
Product handling ........................................................................................................ 20
4.1
Packaging, shipping, storage and moisture preconditioning ............................................................... 20
4.2
Soldering ............................................................................................................................................ 20
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4.3
EOS/ESD/EMI precautions ................................................................................................................... 23
4.4
Applications with cellular modules ...................................................................................................... 26
Appendix .......................................................................................................................... 28
Recommended parts ...................................................................................................................................... 28
Manufacturer .................................................................................................................... 28
Order No. .......................................................................................................................... 28
Comments ......................................................................................................................... 28
Related documents........................................................................................................... 29
Revision history ................................................................................................................ 29
Contact .............................................................................................................................. 30
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1 Hardware description
1.1 Overview
The u-blox LEA-M8F module is a standalone GNSS time and frequency reference product featuring the high
performance u-blox M8 positioning engine. The device provides multi-GNSS synchronization for cost-sensitive
network edge equipment including Small Cell and Femto wireless base-stations. The LEA-M8F module is a fully
self-contained phase and frequency reference based on GNSS, but can also be used as part of a complete timing
sub-system including macro-sniff (network listen), Synchronous Ethernet and packet timing.
The LEA-M8F module includes a low-noise 30.72 MHz VCTCXO meeting the master reference requirements for
LTE Small Cells and providing 100 ppb autonomous hold-over. An external TCXO or OCXO can also be
measured and controlled for TD-LTE, LTE-Advanced and other applications requiring extended hold-over.
External sources of synchronization are supported through time-pulse and frequency inputs and a message
interface. This allows measurements from macro-sniff, Synchronous Ethernet or packet timing to be combined
with measurements from GNSS.
The industry standard LEA form factor in the leadless chip carrier (LCC) package makes the LEA-M8F easy to
integrate, while combining exceptional timing and frequency performance with highly flexible design and
connectivity options. SMT pads allow fully automated assembly with standard pick & place and reflow-soldering
equipment for cost-efficient, high-volume production enabling short time-to-market.
For product features see the LEA-M8F Data Sheet [1].
To determine which u-blox product best meets your needs, see the product selector tables on the u-blox
website www.u-blox.com.
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1.2 Architecture
Figure 1 shows a block schematic view of the module’s internal organization.
Figure 1: LEA-M8F Block Diagram
The device contains all the elements required to implement a multi-GNSS frequency and time synchronization
system. It comprises a u-blox M8030 GNSS receiver, RF LNA/SAW filter and disciplined VCTCXO. A FLASH
memory contains the FTS firmware and provides configuration storage.
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1.3 Pin description for LEA-M8F designs
Function
PIN
No
I/O
Description
Remarks
Power
VCC
6
I
Supply Voltage
Provide a clean and stable supply.
GND
7,
13-
15,
17
I
Ground
Assure a low impedance GND connection to all GND pins of
the module, preferably with a large ground.
V_BCKP
11
I
connect to VCC. (Back-up mode not supported)
VDDUSB
24
I
USB Power Supply
To use the USB interface connect this pin to 3.0 – 3.6 V
derived from VBUS.
If no USB serial port used connect to GND.
Antenna
RF_INPUT
16
I
GPS/GLONASS/
BeiDou/signal input
from antenna
Use a controlled impedance transmission line of 50 Ω to
connect to RF_IN.
Don’t supply DC through this pin. Use V_ANT pin to supply
power.
VCC_RF
18
O
Output Voltage RF
section
Can be used to power an external active antenna Ω). The max
power consumption of the Antenna must not exceed the
datasheet specification of the module.
Leave open if not used.
V_ANT
19
I
Antenna Bias voltage
Connect to GND (or leave open) if Passive Antenna is used. If
an active Antenna is used, add a 10 Ω resistor in front of
V_ANT input to the Antenna Bias Voltage or VCC_RF
Reserved
20
I
Leave open
UART
TxD1/MISO/
TX ready
3
O
Serial Port 1 or SPI
Data i/p
Communication interface o/p function dependent on D_SEL. It
can also can be programmed as TX ready for DDC interface.
Leave open if not used.
RxD1/MOSI
4
I
Serial Port 1 or SPI
Data o/p
Communication interface i/p dependent on D_SEL with
internal pull-up resistor to VCC. Leave open if not used. Don’t
use external pull up resistor.
USB
USB_DM
25
I/O
USB I/O line
USB2.0 bidirectional communication pin. Leave open if
unused. For example implementations see section 1.5.2
USB_DP
26
I/O
USB I/O line
System
RESET_N
10
I
Hardware Reset
(Active Low)
Leave open if not used.
TIMEPULSE/TP2/
SAFEBOOT_N
28
I/O
Timepulse Signal
Configurable Timepulse signal (one pulse per second by
default). Leave open if not used.
FREQ_PHASE_IN0/
EXTINT0
27
I
TimePulse/Frequency
General purpose frequency/phase measurement input 0,
Alternate function: External Interrupt 0
FREQ_PHASE_IN1/
EXTINT1
21
I
TimePulse/Frequency
General purpose frequency/phase measurement input 1
Alternate function: External Interrupt 1
REF_FREQ_OUT
9
I
VCTCXO o/p
Buffered output from the disciplined internal 30.72MHz
VCTCXO
SDA
/CS_N
1
I/O
DDC Data Pin
or SPI chip sel.
DDC Data. Leave open if not used.
or SPI chip select: dependent on DSEL
SCL
/SCLK
2
I/O
DDC Clk Pin
or SPI clk
DDC Clock. Leave open if not used.
or SPI clock: dependent on DSEL
SAFEBOOT_N
12
I
Test-point for service access. Leave open, do not drive low.
D_SEL
5
Selects the
interface protocol
Used to select UART+DDC or SPI
Open = UART+DDC; low = SPI on pins 1,2,3,4
SDA_DAC
22
I/O
DDC Data pin
For DAC control of external Freq Reference Only
SCL_DAC
23
O
DDC Clk pin
For DAC control of external Freq Reference Only
Table 1: LEA-M8F Pinout
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1.4 Connecting power
The u-blox LEA-M8F module has three power supply pins: VCC, V_BCKP and VDD_USB.
1.4.1 VCC
The VCC pin provides the main supply voltage. During operation, the current drawn by the module can vary by
some orders of magnitude. For this reason, it is important that the supply circuitry be able to support the peak
power for a short time. For specification see the LEA-M8F Data Sheet [1].
Use a proper GND concept with preferably low ESR decoupling capacitors at the module supply input.
Do not use any resistors or coils in the power line.
1.4.2 V_BCKP
This pin must be connected to the main module supply VCC.
1.4.3 VCC_RF
The VCC_RF pin provides a filtered source of DC to power an active antenna or external LNA. For more
information, see section 2.2.
1.5 Interfaces
The following interfaces are available for communication with a host for control and data handling.
1.5.1 UART
The LEA-M8F module includes a Universal Asynchronous Receiver Transmitter (UART) serial interface RxD/TxD
supporting configurable baud rates. See the LEA-M8F Data Sheet [1] for the supported baud rates.
The signal input and output levels are 0 V to VCC with inverted logic. An interface based on RS232 standard
levels (+/- 12 V) can be implemented using level shifters such as a Maxim MAX3232.
The interface does not support hardware handshake signals or synchronous operation.
Designs must allow access to the UART and the SAFEBOOT_N pin for future service, updates and
reconfiguration.
1.5.2 USB
A USB 2.0 (Full Speed, 12 Mb/s) compatible interface is available for communication as a development option.
The module is not designed to use the USB interface in an operational sense as the message latency cannot be
guaranteed.
The USB_DP pin has a pull-up resistor to signal a full-speed device to the USB host. The VDD_USB pin requires
connection to a 3 V (nom.) source to enable the USB interface. If the USB interface is not used, connect
VDD_USB to GND.
u-blox provides Microsoft® certified USB drivers for Windows XP, Windows Vista, Windows 7 and Windows 8
operating systems. These drivers are available for down-load at our website: www.u-blox.com
The USB port is for non-operational use e.g. for evaluation or firmware down-load
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1.5.2.1
USB external components
The USB interface requires some external components to comply with the USB 2.0 specification. These are
shown below in Figure 2 and listed in Table 2. To comply with USB specifications, VBUS must be connected
through an LDO (U1) to pin 24 (VDD_USB) to regulate the 5 V VBUS down to a nominal 3.3 V for the module.
The LEA-M8F module USB interface is intended to be used as a USB self-powered device deriving its power
supply from VCC. However, the module power supply (VCC) can be turned off independently of the host VBUS
supplying VDD_USB. With VDD_USB active, the USB host would receive a signal indicating that the device is
present and ready to communicate. This should be avoided by disabling the LDO (U1) using the enable signal
(EN) of the VCC-LDO enabled by e.g. VCC. Depending on the characteristics of the LDO (U1) it is recommended
to add a pull-down resistor (R11) at its output to ensure VDD_USB is not floating if the LDO (U1) is disabled or
the USB cable is disconnected i.e. VBUS is not supplied.
Module
VDD_USB
LDO
VDD_USB
R4
USB_DP
USB_DM
R5
C24
C23
D2
VBUS
DP
DM
GND
USB Device Connector
U1
EN
R11
EN
Figure 2: USB Interface
Name
Component
Function
Comments
U1
LDO
Regulates VBUS (4.4 …5.25 V)
down to a voltage of 3.3 V.
Almost no current requirement (~1 mA) if the GNSS receiver is operated as a
USB self-powered device.
C23,
C24
Capacitors
Required according to the specification of LDO U1
D2
Protection
diodes
Protect circuit from overvoltage
/ ESD when connecting.
Use low capacitance ESD protection such as ST Microelectronics USBLC6-2.
R4, R5
Serial
termination
resistors
Establish a full-speed driver
impedance of 28…44 Ω
A value of 27 Ω is recommended.
R11
Resistor
100 kΩ is recommended for USB self-powered setup. For bus-powered setup,
R11 can be ignored.
Table 2: Summary of USB external components
1.5.3 Display Data Channel (DDC)
An I
2C compatible Display Data Channel (DDC) interface is available for serial communication with an external
host CPU. The interface only supports slave mode operation (master mode is not supported). The DDC protocol
and electrical interface are fully compatible with the Fast-Mode of the I
2C industry standard. The DDC pins SDA
and SCL have internal 10 kΩ pull-up resistors.
For more information about the DDC implementation, see the u-blox M8 Receiver Description Including Protocol
Specification [2]. For bandwidth information, see the LEA-M8F Data Sheet [1]. For timing, parameters consult the
I
2C-bus specification [8].
The u-blox M8 DDC interface supports serial communication with u-blox cellular modules. See the
specification of the applicable cellular module to confirm compatibility.
1.5.4 SPI
An SPI interface is available for communication to a host CPU, however its interface connections are shared with
the UART and DDC interface pins. The SPI interface is not available in the default configuration but can be
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enabled by connecting pin 5 (D_SEL) to ground - see 1.6.2 below. For speed and clock frequency specifications,
see the LEA-M8F Data Sheet [1].
1.5.5 DDC interface for External DAC Control
A dedicated DDC (I2C) interface (pins SDA_DAC, SCL_DAC) is provided for implementations in which the LEA-
M8F controls an external voltage controlled frequency reference via a DAC. This is set up via FTS specific
configuration messages. See the u-blox M8 Receiver Description Protocol Specification [2] and the u-blox M8F
Applications Guide [3] for more information. The DDC pins SDA_DAC and SCL_DAC have internal 10 kΩ pull-
up resistors.
When the LEA-M8F is configured to discipline a voltage controlled oscillator via the dedicated DDC interface
(SDA_DAC, SCL_DAC) a choice must be made with respect to the DAC component. The recommended types
(TI or Microchip) offer 16 or 12 bit resolution respectively and should be chosen for the desired performance/cost
requirements. This section shows a suggested circuitry for implementing a 16 bit TI DAC analog filter
combination connected to a VCTCXO/VCOCXO. Note that 12 bit DAC may not provide sufficient resolution if
used over the full circuit voltage range and hence may compromise the controlled frequency performance.
Implementing a circuit using a smaller DAC voltage range and adding the output to a fixed low noise offset
voltage would be beneficial.
Figure 3: 16 bit DAC connection for VCOCXO control
1.6 I/O and Control Pins
1.6.1 RESET_N
RESET_N is an input-only pin with an internal pull-up resistor. The LEA-M8F performs an automatic reset
function on application of the power supply but this input may also be used to re-start the device during
operation if necessary. The pin must be held low for at least 10 ms to ensure RESET_N is detected. Leave
RESET_N open for normal operation. The RESET_N input complies with the power supply VCC voltage level and
can be actively driven high. Use this pin only to reset the module. Do not use RESET_N to turn the module on
and off since the reset state increases power consumption.
1.6.2 D_SEL
The D_SEL pin selects the available communication interfaces available at the module pins. This allows a choice
between UART+DDC or SPI control of the module, see Table 3 below. If D_SEL is left open both UART and DDC
are available. If pulled low, a single SPI interface is available. See the LEA-M8F Data Sheet [1].
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PIN
PIN 5 (D_SEL) = “high” (left open)
PIN 5 (D_SEL) = “Low” (connected to GND)
1
DDC SDA
SPI CS
2
DDC SCL
SPI CLK
3
UART TX
SPI MISO
4
UART RX
SPI MOSI
Table 3: D_SEL pin configuration
1.6.3 FREQ_PHASE_IN0 / EXINT0, FREQ_PHASE_IN1 / EXTINT1
These two frequency/phase inputs are provided for connecting an external source of phase (pulse stream) or
frequency reference into the module. The pulse stream can be derived from a frequency reference or external
synchronization source. The module will measure and report the phase or frequency offset of this input with
respect to the current synchronization source and optionally steer the related oscillator to bring the externally
derived pulses into alignment.
NB. These two pins have an alternate legacy function as external interrupts and are also called EXTINT0,EXTINT1
for compatibility with standard u-blox M8 functionality.
1.6.4 REF_FREQ_OUT
This pin carries a low phase noise buffered output from the module’s disciplined 30.72MHz VCTCXO (CMOS
buffer via on-module resistor).
1.6.5 TIMEPULSE / TP2
The timepulse signal is output from this pin. This pin is the standard u-blox M8 TP2 output, hence all timepulse
settings must be made with respect to TP2 in UBX control messages.
The timepulse output pin also functions as the SAFEBOOT_N input pin at start up, initiating a special Safe Boot
Mode operation from ROM if held LO during reset (for example for Flash firmware recovery). As a result,
applications using the timepulse output should ensure that this pin is not held LO during start-up in normal
operation. This can be achieved safely by re-buffering the timepulse output using the VDD_IO supply. This pin
has an internal pull-up resistor of nominally 11 kΩ.
1.7 Device Configuration
The device configuration can be modified using UBX protocol configuration messages. Configuration settings
for the FTS functionality are explored further in the accompanying Application Guide [3]. All modified settings
remain effective until power-down or reset. The configuration can be saved permanently in SQI flash using the
UBX-CFG-CFG message. For a full explanation of all configuration messages, refer to the u-blox M8 Receiver
Description Protocol Specification [2].
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2 Design
2.1 Layout: Footprint and paste mask
This section describes the footprint and provides recommendations for the paste mask for the u-blox M8F LCC
module.
These are recommendations only and not specifications. Note that the copper and solder masks have the same
size and position.
To improve the wetting of the half vias, reduce the amount of solder paste under the module and increase the
volume outside of the module by defining the dimensions of the paste mask to form a T-shape (or equivalent)
extending beyond the copper mask. For the stencil thickness, see section 4.2.
Consider the paste mask outline when defining the minimal distance to the next component. The exact
geometry, distances, stencil thicknesses and solder paste volumes must be adapted to the specific
production processes (e.g. soldering) of the customer.
17.0 mm [669 mil]
22.4 mm [881.9 mil]
1.0 mm
[39 mil]
0.8 mm
[31.5 mil]
2.45 mm
[96.5 mil]
1.1 mm
[43 mil]
3.0 mm
[118 mil]
2.15 mm
[84.5 mil]
0.8 mm
[31.5 mil]
Stencil: 150 µm
15.7 mm [618 mil]
17.0 mm [669 mil]
20.8 mm [819 mil]
0.8 mm
[31.5 mil]
0.6 mm
[23.5 mil]
Figure 4: LEA-M8F footprint
Figure 5: LEA-M8F paste mask
2.1.1 Placement
A very important factor in achieving maximum performance is the placement of the receiver on the PCB. The
connection to the antenna must be as short as possible to avoid jamming into the very sensitive RF section.
Make sure that RF critical circuits are clearly separated from any other digital circuits on the system board. To
achieve this, position the receiver digital part towards your digital section of the system PCB. Care must also be
exercised with placing the receiver in proximity to circuitry that can emit heat. The RF part of the receiver is very
sensitive to temperature and sudden changes can have an adverse impact on performance.
The RF part of the receiver is a temperature sensitive component. Avoid high temperature drift
and air vents near the receiver.
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Non 'emitting'
circuits
PCB
Digital & Analog circuits
Non
'emitting'
circuits
Antenna
Digital Part
RF Part
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
RF & heat
'emitting'
circuits
PCB
Digital & Analog circuits
RF& heat
'emitting'
circuits
Antenna
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Figure 6: Placement (for exact pin orientation see LEA-M8F Data Sheet [1])
2.1.2 Antenna connection and ground plane design
The LEA-M8F module can be connected to passive patch or active antennas. The RF connection is on the PCB
and connects the RF_IN pin with the antenna feed point or the signal pin of the connector, respectively. Figure 7
illustrates connection to a typical five-pin RF connector. One can see the improved shielding for digital lines as
discussed in the GPS Antenna Application Note [5]. Depending on the actual size of the ground area, additional
vias should be placed in the outer region. In particular, the edges of the ground area should be terminated with
a dense line of vias.
Figure 7: Recommended layout (for exact pin orientation see the LEA-M8F data sheet [1])
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As seen in Figure 7, an isolated ground area is created around and below the RF connection. This part of the
circuit MUST be kept as far from potential noise sources as possible. Make certain that no signal lines cross, and
that no signal trace vias appear at the PCB surface within the area of the red rectangle. The ground plane should
also be free of digital supply return currents in this area. On a multi layer board, the whole layer stack below the
RF connection should be kept free of digital lines. This is because even solid ground planes provide only limited
isolation.
The impedance of the antenna connection has to match the 50 Ω impedance of the receiver. To achieve an
impedance of 50 Ω, the width W of the micro strip has to be chosen depending on the dielectric thickness H,
the dielectric constant εr of the dielectric material of the PCB, and on the build-up of the PCB (see section 2.1.3).
Figure 8 shows two different builds: A 2-layer PCB and a 4-layer PCB. The reference ground plane is on layer 2 in
both designs. Therefore, the effective thickness of the dielectric is different.
Module
micro strip line
Ground plane
Module
micro strip line
Ground plane
PCB
PCB
Either don't use these layers or fill with ground planes
H
H
Figure 8: PCB build-up for micro strip line. Left: 2-layer PCB, right: 4-layer PCB
General design recommendations:
•
The length of the micro strip line should be kept as short as possible. Lengths over 2.5 cm (1 inch) should be
avoided on standard PCB material and without additional shielding.
•
For multi-layer boards, the distance between micro strip line and ground area on the top layer should at
least be as large as the dielectric thickness.
•
Routing the RF connection close to digital sections of the design should be avoided.
•
To reduce signal reflections, sharp angles in the routing of the micro strip line should be avoided. Chamfers
or fillets are preferred for rectangular routing; 45-degree routing is preferred over Manhattan style
90-degree routing.
Antenna
Antenna
Antenna
PCB
PCB
PCB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Wrong
better
best
Figure 9: Recommended micro strip routing to RF pin (for exact pin orientation see LEA-M8F Data Sheet [1])
•
Do not route the RF-connection underneath the receiver. The distance of the micro strip line to the ground
plane on the bottom side of the receiver is very small (some 100 µm) and has huge tolerances (up to 100%).
Therefore, the impedance of this part of the trace cannot be controlled.
•
Use as many vias as possible to connect the ground planes.
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•
In order to avoid reliability hazards, the area on the PCB under the receiver should be entirely covered with
solder mask. Vias should not be open. Do not route under the receiver.
2.1.3 Antenna micro strip connection
There are many ways to design wave-guides on printed circuit boards. Common to all is that calculation of the
electrical parameters is not straightforward. Freeware tools like AppCAD from Avago Technologies or TXLine
from
Applied
Wave
Research,
Inc.
are
of
great
help.
They
can
be
downloaded
from
http://www.avagotech.com/pages/appcad or http://www.hp.woodshot.com/ and www.mwoffice.com.
The micro strip is the most common RF interconnect configuration for printed circuit boards. The basic
configuration is shown in Figure 10 and Figure 11. As a rule of thumb, for an FR-4 material the width of the
conductor is roughly double the thickness of the dielectric to achieve 50 Ω line impedance.
For the correct calculation of the micro strip impedance, not only must one consider the distance between the
top and the first inner layer, but also the distance between the micro strip and the adjacent GND plane on the
same layer.
Use the Coplanar Waveguide model for the calculation of the micro strip dimensions.
Figure 10: Micro strip on a 2-layer board (Agilent AppCAD Coplanar Waveguide)
Figure 10 shows an example of a 2-layer FR4 board with 1.6 mm thickness and a 35 µm (1 ounce) copper
cladding. The thickness of the micro strip is comprised of the cladding (35 µm) plus the plated copper (typically
25 µm). Figure 11 is an example of a multi layer FR4 board with 18 µm (½ ounce) cladding and 180 µ dielectric
between layer 1 and 2.
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Figure 11: Micro strip on a multi layer board (Agilent AppCAD Coplanar Waveguide)
2.2 GNSS Antenna Connection
2.2.1 Passive Antenna Connection
A design using a passive antenna requires more attention to the layout of the RF section. Typically, a passive
antenna is located near electronic components; therefore take care to reduce electrical noise that may interfere
with the antenna performance. Passive antennas do not require a DC bias voltage and can be directly connected
to the RF input pin, RF_IN. Sometimes, they may also need a passive matching network to match the impedance
to 50 Ω.
Figure 12 shows a minimal setup for a design with a good GNSS patch antenna.
Figure 12: Module design with passive antenna (for exact pin orientation see the LEA-M8F Data Sheet[1])
Use an antenna that has sufficient bandwidth to receive all GNSS constellations. See the recommended
types in the Appendix.
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2.2.2 Active antenna connection
Active antennas have an integrated low-noise amplifier. Typically, they require an additional 5 to 20 mA that
will contribute to the total GNSS system power consumption.
If the supply voltage of the u-blox M8 receiver matches the supply voltage range of the antenna (e.g. 3.0 V), use
the filtered supply voltage at VCC_RF to supply the antenna DC power. The V_ANT pin provides a current
limited supply connection to the RF_IN pin for antenna LNA biasing, see Figure 13 below.
Figure 13: Active antenna design, external supply from VCC_RF (for exact pin orientation see LEA-M8F Data Sheet [1])
For powering an active antenna with an alternative voltage to the module VCC, use an external supply as shown
in Figure 14.
Figure 14: Active antenna design, direct external supply (for exact pin orientation see the LEA-M8F Data Sheet [1])
When the VCC_RF voltage does not match with the antenna supply voltage, use a filtered external
supply as shown in Figure 14.
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3 Migration to u-blox M8 modules
u-blox is committed to ensuring that products in the same form factor are backwards compatible over several
technology generations. Utmost care has been taken to minimize impact on function and performance and to
make u-blox M8 modules as compatible as possible with earlier modules.
Make sure that the RF path (antenna and filtering parameters) matches that of the GNSS constellations used.
To use BeiDou, review the bandwidth of the external RF components and the antenna. For information about
power consumption, see the LEA-M8F Data Sheet [1].
It is highly advisable that customers consider a design review with the u-blox support team to ensure the
compatibility of key functionalities.
3.1 Software migration
For an overall description of the module software operation, see the u-blox M8 Receiver Description
including Protocol Specification [2]
For software migration details, see the u-blox 7 to u-blox M8 Software Migration Guide [4].
3.2 Hardware migration LEA-6T -> LEA-M8F
This section compares the functionality when a design is migrated from a LEA-6T to a LEA-M8F. Most pins are
compatible however, the following items have changed:-
•
A single timepulse (TP2) output
•
USB interface not recommended for operational use
•
No back-up battery operation supported
•
Interface option serial/SPI selectable by D_SEL line
•
No antenna supervisor(status) function
•
Timepulse 2 replaced with output frequency signal REF_FREQ_OUT
The Timepulse output from LEA-M8F must be allowed to float during start-up and reset (see section 1.6.5)
Table 4 outlines the difference in pin connections between the two modules.
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Pin
No.
LEA-6T
LEA-M8F
Remarks for Migration
Pin Name
Typical Assignment
Pin Name
Typical Assignment
1
SDA2
DDC Pins
SDA2/CS_N
DDC data or SPI chip
select
Depends on D_SEL (pin 5) status
2
SCL2
DDC Pins
SCL2/SCLK
DDC clock or SPI clock
Depends on D_SEL (pin 5) status
3
TxD1
Serial Port 1
TxD1/MISO
UART TX or SPI MISO
Depends on D_SEL (pin 5) status
4
RxD1
Serial Port 1
RxD1/MOSI
UART RX or SPI MOSI
Depends on D_SEL (pin 5) status
5
NC
Leave open
DSEL
Interface type
selection
Used to select UART+DDC or SPI only
Open = UART+DDC; GND = SPI on pins
1,2,3,4
6
VCC
Supply Voltage
VCC
Supply Voltage
No difference
7
GND
Ground
GND
Ground
No difference
8
VCC_OUT
Leave open if not
used.
VCC_OUT
Leave open if not used.
No difference
9
Timepulse
TimePulse2 o/p
REF_FREQ_OUT
VCTCXO o/p
Module VCTCXO signal o/p
10
RESET_N
Hardware Reset
(Active Low)
RESET_N
Hardware Reset (Active
Low)
11
V_BCKP
Backup voltage
supply
V_BCKP
Backup voltage
supply
Back-up operation not supported -
Connect to Vcc
12
SAFEBOOT_
N
GND
Reserved
Leave Open
Test-point for service access
13
GND
GND
GND
GND
No difference
14
GND
GND
GND
GND
No difference
15
GND
GND
GND
GND
No difference
16
RF_IN
RF input
RF_IN
RF input
No difference
17
GND
GND
GND
GND
No Difference
18
VCC_RF
O/P Voltage for RF
section
VCC_RF
O/P Voltage for RF
section
No difference
19
V_ANT
Ant. Bias V
V_ANT
Ant. Bias V
No difference
20
AADET_N
Active Antenna
Detect
Reserved
Leave Unconnected
No Antenna Supervision
21
NC
No Connection
FREQ_PHASE_I
N1/ EXTINT1
2
nd Freq/ PPS input
22
NC
No Connection
SDA_DAC
DDC pin for Ext DAC
o/p
.
23
NC
No Connection
SCL_DAC
DDC pin for Ext DAC
o/p
24
VDD USB
USB Voltage
Source
VDD USB
USB Voltage Source
Not supported for operational use
25
USB_DM
USB I/O Line -
USB I/O Line
USB I/O Line -
Not supported for operational use
26
USB_DP
USB I/O Line +
USB I/O Line
USB I/O Line +
Not supported for operational use
27
EXTINT0
Ext. Interupt
FREQ_PHASE_IN
0/ EXTINT0
1
st Freq/ PPS input
28
Timepulse
Timepulse signal
Timepulse/TP2/
SAFEBOOT_N
Timepulse signal
SAFEBOOT_N
Timepulse is TP2
Must float during reset (see 1.6.5)
Table 4: Pin-out comparison LEA-6T vs. LEA-M8F
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4 Product handling
4.1 Packaging, shipping, storage and moisture preconditioning
For information pertaining to reels and tapes, Moisture Sensitivity levels (MSL), shipment and storage
information, as well as drying for preconditioning see the LEA-M8F Data Sheet [1].
Population of Modules
When populating the modules, make sure that the pick and place machine is aligned to the copper pins
of the module and not on the module edge.
4.2 Soldering
Soldering paste
Use of "No Clean" soldering paste is strongly recommended, as it does not require cleaning after the soldering
process has taken place. The paste listed in the example below meets these criteria.
Soldering Paste:
OM338 SAC405 / Nr.143714 (Cookson Electronics)
Alloy specification:
Sn 95.5/ Ag 4/ Cu 0.5 (95.5% Tin/ 4% Silver/ 0.5% Copper)
Melting Temperature:
217 °C
Stencil Thickness:
See section 2.1
The final choice of the soldering paste depends on the approved manufacturing procedures.
The paste-mask geometry for applying soldering paste should meet the recommendations.
The quality of the solder joints on the connectors (’half vias’) should meet the appropriate IPC
specification.
Reflow soldering
A convection type-soldering oven is highly recommended over the infrared type radiation oven.
Convection heated ovens allow precise control of the temperature, and all parts will heat up evenly, regardless
of material properties, thickness of components and surface color.
As a reference, see the "IPC-7530 Guidelines for temperature profiling for mass soldering (reflow and wave)
processes”, published in 2001.
Preheat phase
During the initial heating of component leads and balls, residual humidity will be dried out. Note that this
preheat phase will not replace prior baking procedures.
•
Temperature rise rate: max. 3 °C/s. If the temperature rise is too rapid in the preheat phase it may cause
excessive slumping.
•
Time: 60 - 120 s. If the preheat is insufficient, rather large solder balls tend to be generated. Conversely, if
performed excessively, fine balls and large balls will be generated in clusters.
•
End Temperature: 150 - 200 °C. If the temperature is too low, non-melting tends to be caused in areas
containing large heat capacity.
Heating/ Reflow phase
The temperature rises above the liquidus temperature of 217°C. Avoid a sudden rise in temperature as the slump
of the paste could become worse.
•
Limit time above 217 °C liquidus temperature: 40 - 60 s
•
Peak reflow temperature: 245 °C
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Cooling phase
A controlled cooling avoids negative metallurgical effects (solder becomes more brittle) of the solder and
possible mechanical tensions in the products. Controlled cooling helps to achieve bright solder fillets with a good
shape and low contact angle.
•
Temperature fall rate: max 4 °C/s
To avoid falling off, the u-blox M8 GNSS module should be placed on the topside of the motherboard
during soldering.
The final soldering temperature chosen at the factory depends on additional external factors like choice of
soldering paste, size, thickness and properties of the base board, etc. Exceeding the maximum soldering
temperature in the recommended soldering profile may permanently damage the module.
Figure 15: Recommended soldering profile
u-blox M8 modules must not be soldered with a damp heat process.
Optical inspection
After soldering the u-blox M8 module, consider an optical inspection step to check whether:
•
The module is properly aligned and centered over the pads
•
All pads are properly soldered
•
No excess solder has created contacts to neighboring pads, or possibly to pad stacks and vias nearby
Cleaning
In general, cleaning the populated modules is strongly discouraged. Residues underneath the modules cannot
easily be removed with a washing process.
•
Cleaning with water will lead to capillary effects where water is absorbed in the gap between the baseboard
and the module. The combination of residues of soldering flux and encapsulated water leads to short circuits
or resistor-like interconnections between neighboring pads.
•
Cleaning with alcohol or other organic solvents can result in soldering flux residues flooding into the two
housings, areas that are not accessible for post-wash inspections. The solvent will also damage the sticker
and the ink-jet printed text.
•
Ultrasonic cleaning will permanently damage the module, in particular the quartz oscillators.
The best approach is to use a "no clean" soldering paste and eliminate the cleaning step after the soldering.
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Repeated reflow soldering
Only single reflow soldering processes are recommended for boards populated with u-blox M8 modules. u-blox
M8 modules should not be submitted to two reflow cycles on a board populated with components on both sides
in order to avoid upside down orientation during the second reflow cycle. In this case, the module should always
be placed on that side of the board, which is submitted into the last reflow cycle. The reason for this (besides
others) is the risk of the module falling off due to the significantly higher weight in relation to other
components.
Two reflow cycles can be considered by excluding the above described upside down scenario and taking into
account the rework conditions described in Section Product handling.
Repeated reflow soldering processes and soldering the module upside down are not recommended.
Wave soldering
Base boards with combined through-hole technology (THT) components and surface-mount technology (SMT)
devices require wave soldering to solder the THT components. Only a single wave soldering process is
encouraged for boards populated with u-blox M8 modules.
Hand soldering
Hand soldering is allowed. Use a soldering iron temperature setting equivalent to 350 °C and carry out the hand
soldering according to the IPC recommendations / reference documents IPC7711. Place the module precisely on
the pads. Start with a cross-diagonal fixture soldering (e.g. pins 1 and 15), and then continue from left to right.
Rework
The u-blox M8 module can be unsoldered from the baseboard using a hot air gun. When using a hot air gun for
unsoldering the module, a maximum of one reflow cycle is allowed. In general, we do not recommend using a
hot air gun because this is an uncontrolled process and might damage the module.
Attention: use of a hot air gun can lead to overheating and severely damage the module.
Always avoid overheating the module.
After the module is removed, clean the pads before placing and hand soldering a new module.
Never attempt a rework on the module itself, e.g. replacing individual components. Such
actions immediately terminate the warranty.
In addition to the two reflow cycles, manual rework on particular pins by using a soldering iron is allowed. For
hand soldering the recommendations in IPC 7711 should be followed. Manual rework steps on the module can
be done several times.
Conformal coating
Certain applications employ a conformal coating of the PCB using HumiSeal
® or other related coating products.
These materials affect the HF properties of the GNSS module and it is important to prevent them from flowing
into the module. The RF shields do not provide 100% protection for the module from coating liquids with low
viscosity; therefore, care is required in applying the coating.
Conformal Coating of the module will void the warranty.
Casting
If casting is required, use viscose or another type of silicon pottant. The OEM is strongly advised to qualify such
processes in combination with the u-blox M8 module before implementing this in the production.
Casting will void the warranty.
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Grounding metal covers
Attempts to improve grounding by soldering ground cables, wick or other forms of metal strips directly onto the
EMI covers is done at the customer's own risk. The numerous ground pins should be sufficient to provide
optimum immunity to interferences and noise.
u-blox makes no warranty for damages to the u-blox M8 module caused by soldering metal cables or
any other forms of metal strips directly onto the EMI covers.
Use of ultrasonic processes
Some components on the u-blox M8 module are sensitive to Ultrasonic Waves. Use of any Ultrasonic Processes
(cleaning, welding etc.) may cause damage to the GNSS Receiver.
u-blox offers no warranty against damages to the u-blox M8 module caused by any Ultrasonic Processes.
4.3 EOS/ESD/EMI precautions
When integrating GNSS positioning modules into wireless systems, careful consideration must be given to
electromagnetic and voltage susceptibility issues. Wireless systems include components that can produce
Electrical Overstress (EOS) and Electro-Magnetic Interference (EMI). CMOS devices are more sensitive to such
influences because their failure mechanism is defined by the applied voltage, whereas bipolar semiconductors
are more susceptible to thermal overstress. The following design guidelines are provided to help in designing
robust yet cost effective solutions.
To avoid overstress damage during production or in the field it is essential to observe strict
EOS/ESD/EMI handling and protection measures.
To prevent overstress damage at the RF_IN of your receiver, never exceed the maximum input
power (see LEA-M8F Data Sheet 0).
Electrostatic discharge (ESD)
Electrostatic discharge (ESD) is the sudden and momentary electric current that flows between
two objects at different electrical potentials caused by direct contact or induced by an
electrostatic field. The term is usually used in the electronics and other industries to describe
momentary unwanted currents that may cause damage to electronic equipment.
ESD handling precautions
ESD prevention is based on establishing an Electrostatic Protective Area (EPA). The EPA can be a small working
station or a large manufacturing area. The main principle of an EPA is that there are no highly charging materials
near ESD sensitive electronics, all conductive materials are grounded, workers are grounded, and charge build-up
on ESD sensitive electronics is prevented. International standards are used to define typical EPA and can be
obtained for example from International Electrotechnical Commission (IEC) or American National Standards
Institute (ANSI).
GNSS positioning modules are sensitive to ESD and require special precautions when handling. Particular care
must be exercised when handling patch antennas, due to the risk of electrostatic charges. In addition to
standard ESD safety practices, the following measures should be taken into account whenever handling the
receiver.
•
Unless there is a galvanic coupling between the local GND (i.e. the
work table) and the PCB GND, then the first point of contact when
handling the PCB must always be between the local GND and PCB
GND.
•
Before mounting an antenna patch, connect ground of the device
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•
When handling the RF pin, do not come into contact with any
charged capacitors and be careful when contacting materials that
can develop charges (e.g. patch antenna ~10 pF, coax cable ~50 -
80 pF/m, soldering iron, …)
•
To prevent electrostatic discharge through the RF input, do not
touch any exposed antenna area. If there is any risk that such
exposed antenna area is touched in non ESD protected work area,
implement proper ESD protection measures in the design.
•
When soldering RF connectors and patch antennas to the receiver’s
RF pin, make sure to use an ESD safe soldering iron (tip).
Failure to observe these precautions can result in severe damage to the GNSS module!
ESD protection measures
GNSS positioning modules are sensitive to Electrostatic Discharge (ESD). Special precautions
are required when handling.
For more robust designs, employ additional ESD protection measures. Using an LNA with appropriate
ESD rating can provide enhanced GNSS performance with passive antennas and increases ESD
protection.
Most defects caused by ESD can be prevented by following strict ESD protection rules for production and
handling. When implementing passive antenna patches or external antenna connection points, then additional
ESD measures can also avoid failures in the field as shown in Figure 16.
Small passive antennas (<2 dBic and
performance critical)
Passive antennas (>2 dBic or performance
sufficient)
Active antennas
A
RF_IN
GNSS
Receiver
LNA
B
L
RF_IN
GNSS
Receiver
C
LNA with appropriate ESD rating
Figure 16: ESD Precautions
Protection measure A is preferred because it offers the best GNSS performance and best level of ESD
protection.
Electrical Overstress (EOS)
Electrical Overstress (EOS) usually describes situations when the maximum input power exceeds the maximum
specified ratings. EOS failure can happen if RF emitters are close to a GNSS receiver or its antenna. EOS causes
damage to the chip structures. If the RF_IN is damaged by EOS, it is hard to determine whether the chip
structures have been damaged by ESD or EOS.
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EOS protection measures
For designs with GNSS positioning modules and wireless (e.g. GSM/GPRS) transceivers in close proximity,
ensure sufficient isolation between the wireless and GNSS antennas. If wireless power output causes the
specified maximum power input at the GNSS RF_IN to be exceeded, employ EOS protection measures to
prevent overstress damage.
For robustness, EOS protection measures as shown in Figure 17 are recommended for designs combining
wireless communication transceivers (e.g. GSM, GPRS) and GNSS in the same design or in close proximity.
Small passive antennas (<2 dBic
and performance critical)
Passive antennas (>2 dBic or
performance sufficient)
Active antennas (without internal filter which need the
module antenna supervisor circuits)
D
RF_IN
GNSS
Receiver
LNA
GPS
Bandpass
Filtler
E
RF_IN
GNSS
Receiver
L
GPS
Bandpass
Filtler
F
LNA with appropriate ESD rating and
maximum input power
GNSS Band pass Filter: SAW or
Ceramic with low insertion loss and
appropriate ESD rating
Figure 17: EOS and ESD Precautions
Electromagnetic interference (EMI)
Electromagnetic interference (EMI) is the addition or coupling of energy originating from any RF emitting device.
This can cause a spontaneous reset of the GNSS receiver or result in unstable performance. Any unshielded line
or segment (>3mm) connected to the GNSS receiver can effectively act as antenna and lead to EMI disturbances
or damage.
The following elements are critical regarding EMI:
•
Unshielded connectors (e.g. pin rows etc.)
•
Weakly shielded lines on PCB (e.g. on top or bottom layer and especially at the border of a PCB)
•
Weak GND concept (e.g. small and/or long ground line connections)
EMI protection measures are recommended when RF emitting devices are near the GNSS receiver. To minimize
the effect of EMI a robust grounding concept is essential. To achieve electromagnetic robustness follow the
standard EMI suppression techniques.
http://www.murata.com/products/emc/knowhow/index.html
http://www.murata.com/products/emc/knowhow/pdf/4to5e.pdf
Improved EMI protection can be achieved by inserting a resistor (e.g. R>20 Ω) or better yet a ferrite bead
(BLM15HD102SN1) or an inductor (LQG15HS47NJ02) into any unshielded PCB lines connected to the GNSS
receiver. Place the resistor as close as possible to the GNSS receiver pin.
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Example of EMI protection measures on the RX/TX line using a ferrite bead:
VCC can be protected using a feed thru capacitor. For electromagnetic compatibility (EMC) of the RF_IN pin,
refer to section Soldering.
4.4 Applications with cellular modules
GSM uses power levels up to 2 W (+33 dBm). Consult the Data Sheet for the absolute maximum power input at
the GNSS receiver.
See the GPS Implementation and Aiding Features in u-blox wireless modules [9].
Isolation between GNSS and GSM antenna
In a handheld type design, an isolation of approximately 20 dB can be reached with careful placement of the
antennas. If such isolation cannot be achieved, e.g. in the case of an integrated GSM/GNSS antenna, an
additional input filter is needed on the GNSS side to block the high energy emitted by the GSM transmitter.
Examples of these kinds of filters would be the SAW Filters from Epcos (B9444 or B7839) or Murata.
Increasing jamming immunity
Jamming signals come from in-band and out-band frequency sources.
In-band jamming
With in-band jamming, the signal frequency is very close to the GNSS constellation frequency used, e.g. GPS
frequency of 1575 MHz (see Figure 19). Such jamming signals are typically caused by harmonics from displays,
micro-controller, bus systems, etc.
1525
1550
1625
GPS input filter
characteristics
1575
1600
0
-110
Jammin
g signal
1525
1550
1625
Frequency [MHz]
Power [dBm]
GPS input filter
characteristics
1575
1600
0
Jamming
signal
GPS
signals
GPS Carrier
1575.4 MHz
Figure 19: In-band jamming signals
TX
RX
GNSS
Receiver
FB
FB
BLM15HD102SN1
>10mm
Figure 18: EMI Precautions
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Figure 20: In-band jamming sources
Measures against in-band jamming include:
•
Maintaining a good grounding concept in the design
•
Shielding
•
Layout optimization
•
Filtering
•
Placement of the GNSS antenna
•
Adding a CDMA, GSM, WCDMA band pass filter before handset antenna
Out-band jamming
Out-band jamming is caused by signal frequencies that are different from the GNSS carrier (see Figure 21). The
main sources are wireless communication systems such as GSM, CDMA, WCDMA, Wi-Fi, BT, etc.
0
500
1000
1500
2000
GPS input filter
characteristics
0
-110
0
500
1500
2000
Frequency [MHz]
GSM
900
GSM
1800
GSM
1900
Power [dBm]
GPS input filter
characteristics
GPS
1575
0
-110
GPS
signals
GSM
950
Figure 21: Out-band jamming signals
Measures against out-band jamming include maintaining a good grounding concept in the design and adding a
SAW or band pass ceramic filter (as recommend in Section 4) into the antenna input line to the GNSS receiver
(see Figure 22).
Figure 22: Measures against in-band jamming
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Appendix
Recommended parts
Recommended parts are selected on a data sheet basis only. Other components may also be used.
Manufacturer Part ID
Remarks
Parameters to consider
Diode ON
Semiconductor
ESD9R3.3ST5G
Standoff Voltage>3.3 V
Low Capacitance < 0.5 pF
ESD9L3.3ST5G
Standoff Voltage>3.3 V
Standoff Voltage > Voltage for active antenna
ESD9L5.0ST5G
Standoff Voltage>5 V
Low Inductance
SAW
TDK/ EPCOS
B8401: B39162-B8401-P810
GPS+GLONASS
High attenuation
TDK/ EPCOS
B3913: B39162B3913U410
GPS+GLONASS+BeiDou
For automotive application
TDK/ EPCOS
B4310: B39162B4310P810
GPS+GLONASS
Compliant to the AEC-Q200 standard
ReyConns
NDF9169
GPS+GLONASS
Low insertion loss, Only for mobile application
muRata
SAFFB1G56KB0F0A
GPS+GLONASS+BeiDou
Low insertion loss, Only for mobile application
muRata
SAFEA1G58KB0F00
GPS+GLONASS
Low insertion loss, only for mobile application
muRata
SAFEA1G58KA0F00
GPS+GLONASS
High attenuation, only for mobile application
muRata
SAFFB1G58KA0F0A
GPS+GLONASS
High attenuation, only for mobile application
muRata
SAFFB1G58KB0F0A
GPS+GLONASS
Low insertion loss, Only for mobile application
TAI-SAW
TA1573A
GPS+GLONASS
Low insertion loss
TAI-SAW
TA1343A
GPS+GLONASS+BeiDou
Low insertion loss
TAI-SAW
TA0638A
GPS+GLONASS+BeiDou
Low insertion loss
LNA
JRC
NJG1143UA2
LNA
Low noise figure, up to 15 dBm RF input power
DAC
TI
DAC8571
Osc. Control Voltage
No of bits (16)
MicroChip
MCP4726
Osc. Control Voltage
No of bits (12)
Inductor
Murata
LQG15HS27NJ02
L, 27 nH
Impedance @ freq GPS > 500 Ω
Capacitor
Murata
GRM1555C1E470JZ01
C, 47 pF
DC-block
Ferrite
Bead
Murata
BLM15HD102SN1
FB
High IZI @ fGSM
Feed thru Murata
Capacitor
for Signal
NFL18SP157X1A3
Monolithic Type
Array Type
Load Capacitance appropriate to signal rate
NFA18SL307V1A45
Feed thru
Capacitor
Murata
NFM18PC ….
NFM21P….
0603 2A
0805 4A
Rs < 0.5 Ω
Resistor
10 Ω ± 10%, min 0.250 W
Rbias
560 Ω ± 5%
R2
100 kΩ ± 5%
R3, R4
Table 5: Recommended parts
Recommended Antennas
Table 6: Recommend antenna
Manufacturer
Order No.
Comments
Hirschmann (www.hirschmann-car.com)
GLONASS 9 M
GPS+GLONASS active
Taoglas (www.taoglas.com )
AA.160.301111
36*36*4 mm, 3-5 V 30 mA active
Taoglas (www.taoglas.com )
AA.161.301111
36*36*3 mm, 1.8 to 5.5 V / 10 mA at 3 V active
INPAQ (www.inpaq.com.tw)
B3G02G-S3-01-A
2.7 to 3.9 V / 10 mA active
Amotech (www.amotech.co.kr)
B35-3556920-2J2
35x35x3 mm GPS+GLONASS passive
Amotech (www.amotech.co.kr)
A25-4102920-2J3
25x25x4 mm GPS+GLONASS passive
Amotech (www.amotech.co.kr)
A18-4135920-AMT04
18x18x4 mm GPS+GLONASS passive
INPAQ (www.inpaq.com.tw)
ACM4-5036-A1-CC-S
5.2 x 3.7 x 0.7 mm GPS+GLONASS passive
Additional antenna Manufacturer: Allis Communications, 2J, Tallysman Wireless
LEA-M8F - Hardware Integration Manual
UBX-14000034 - R03
Early Production Information
Appendix
Page 29 of 30
Related documents
[1]
LEA-M8F Data Sheet, Doc. No. UBX-14001772
[2]
u-blox M8 Receiver Description Protocol Specification, Doc. No. UBX-14002171
[3]
ublox M8F Applications Guide, Doc No. UBX-14001603
[4]
u-blox 7 to u-blox M8 Software Migration Guide, Doc. No. UBX-13003254
[5]
GPS Antenna Application Note, Docu. No. GPS-X-08014
[6]
UBX-M8030 Data Sheet, Docu. No. UBX-13001634
[7]
GPS Compendium, Docu. No. GPS-X-02007
[8]
I
2C-bus specification, Version 2.1, Jan 2000,
http://www.nxp.com/acrobat_download/literature/9398/39340011_21.pdf
[9]
GPS Implementation and Aiding Features in u-blox wireless modules, Docu. No. GSM.G1-CS-09007
For regular updates to u-blox documentation and to receive product change notifications, register on
our homepage (http://www.u-blox.com)
Revision history
Revision
Date
Name
Status / Comments
R01
20-Mar-2014
byou
Objective Specification
R02
05-Jun-2014
smos
Advance Information; Renamed FREQ_PHASE_IN pins from 1, 2 to 0, 1 to match
EXTINT pins.
R03
19-Aug-2014
amil
Early Production Information. Updated Pin12 and Pin28 information in Table 1 and
section 3.2; added design recommendation in section 1.5.1; updated section 1.6.5
(SAFEBOOT_N pin);
LEA-M8F - Hardware Integration Manual
UBX-14000034 - R03
Early Production Information
Contact
Page 30 of 30
Contact
u-blox Offices
North, Central and South
America
u-blox America, Inc.
Phone:
+1 703 483 3180
E-mail:
[email protected]
Regional Office West Coast:
Phone:
+1 408 573 3640
E-mail:
[email protected]
Technical Support:
Phone:
+1 703 483 3185
E-mail:
[email protected]
Headquarters
Europe, Middle East, Africa
u-blox AG
Phone:
+41 44 722 74 44
E-mail:
[email protected]
Support:
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Asia, Australia, Pacific
u-blox Singapore Pte. Ltd.
Phone:
+65 6734 3811
E-mail:
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Support:
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Phone:
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Support:
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Phone:
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Support:
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Phone:
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Support:
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Support:
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Phone:
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Support:
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Phone:
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Support:
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Phone:
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Support:
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