Abstract
This document describes the features and specifications of the u-blox MAX-8 / MAX-M8 module
series.
www.u-blox.com
UBX-15030059 - R06
MAX-8 / MAX-M8
u-blox 8 / M8 GNSS modules
Hardware integration manual
MAX-8 / MAX-M8 - Hardware integration manual
Title
MAX-8 / MAX-M8
Subtitle
u-blox 8 / M8 GNSS modules
Document type
Hardware integration manual
Document number
UBX-15030059
Revision and date
R06
27-May-2020
Document status
Production Information
Product status
Corresponding content status
In Development /
Prototype
Objective Specification
Target values. Revised and supplementary data will be published later.
Engineering Sample
Advance Information
Data based on early testing. Revised and supplementary data will be published later.
Initial Production
Early Production Information
Data from product verification. Revised and supplementary data may be published later.
Mass Production /
End of Life
Production Information
Document contains the final product specification.
European Union regulatory compliance
MAX-8 / MAX-M8 complies with all relevant requirements for RED 2014/53/EU. The MAX-8 / MAX-M8 Declaration of
Conformity (DoC) is available at www.u-blox.com within Support > Product resources > Conformity Declaration.
Product name
Type number
Firmware version
PCN reference
MAX-M8C
MAX-M8C-0-10
ROM SPG 3.01
UBX-16013125
MAX-M8W
MAX-M8W-0-10
ROM SPG 3.01
UBX-16013125
MAX-M8Q
MAX-M8Q-0-10
ROM SPG 3.01
UBX-16013125
MAX-8Q
MAX-8Q-0-10
ROM SPG 3.01
N/A
MAX-8C
MAX-8C-0-10
ROM SPG 3.01
N/A
u-blox or third parties may hold intellectual property rights in the products, names, logos and designs included in this
document. Copying, reproduction, modification or disclosure to third parties of this document or any part thereof is only
permitted with the express written permission of u-blox.
The information contained herein is provided “as is” and u-blox assumes no liability for its use. No warranty, either express or
implied, is given, including but not limited to, 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 without notice. For the most recent
documents, visit www.u-blox.com.
Copyright © u-blox AG.
Document information
This document applies to the following products:
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MAX-8 / MAX-M8 - Hardware integration manual
Contents
Document information ................................................................................................................................ 2
Contents .......................................................................................................................................................... 3
1 Hardware description ........................................................................................................................... 5
1.1 Overview ........................................................................................................................................................ 5
1.2 Configuration ............................................................................................................................................... 5
1.3 Connecting power ....................................................................................................................................... 5
1.3.1 VCC_IO: IO supply voltage ................................................................................................................. 6
1.3.2 V_BCKP: Backup supply voltage ...................................................................................................... 6
1.3.3 VCC_RF: Output voltage RF ............................................................................................................. 7
1.3.4 V_ANT: Antenna supply (MAX-M8W) ............................................................................................. 7
1.4 Interfaces ...................................................................................................................................................... 7
1.4.1 UART ..................................................................................................................................................... 7
1.4.2 Display data channel (DDC) .............................................................................................................. 7
1.4.3 TX_READY ............................................................................................................................................ 7
1.5 I/O pins ........................................................................................................................................................... 8
1.5.1 RESET_N: Reset input ....................................................................................................................... 8
1.5.2 EXTINT: External interrupt ............................................................................................................... 8
1.5.3 SAFEBOOT_N ...................................................................................................................................... 8
1.5.4 TIMEPULSE.......................................................................................................................................... 8
1.5.5 LNA_EN: LNA enable .......................................................................................................................... 8
1.5.6 ANT_DET: Open circuit detection (MAX-M8) ............................................................................... 9
1.6 Electromagnetic interference on I/O lines ............................................................................................. 9
2 Design ..................................................................................................................................................... 11
2.1 Pin description ...........................................................................................................................................11
2.1.1 Pin name changes.............................................................................................................................11
2.2 Minimal design...........................................................................................................................................12
2.3 Layout: Footprint and paste mask ........................................................................................................12
2.4 Antenna and antenna supervision ........................................................................................................13
2.4.1 Antenna design with passive antenna .........................................................................................13
2.4.2 Antenna design with active antenna ............................................................................................14
2.4.3 Antenna design with active antenna using antenna supervisor (MAX-M8W) ....................15
2.4.4 Status reporting ...............................................................................................................................16
2.4.5 Power and short detection antenna supervisor (MAX-M8W) .................................................16
2.4.6 Power, short and open detection antenna supervisor (MAX-M8W) ......................................18
2.5 Layout design-in: Thermal management .............................................................................................18
3 Migration to u-blox 8 / M8 modules .............................................................................................. 20
3.1 Migrating u-blox 7 designs to u-blox 8 / M8 modules ........................................................................20
3.2 Hardware migration from MAX-6 to MAX-8 / M8 ...............................................................................20
3.3 Software migration ...................................................................................................................................21
4 Product handling ................................................................................................................................. 22
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4.1 Packaging, shipping, storage and moisture preconditioning ..........................................................22
4.2 Soldering .....................................................................................................................................................22
4.3 EOS/ESD/EMI precautions ......................................................................................................................25
4.4 Applications with cellular modules ........................................................................................................28
Appendix ....................................................................................................................................................... 30
A Glossary ................................................................................................................................................. 30
B Recommended components ........................................................................................................... 30
Related documents ................................................................................................................................... 32
Revision history .......................................................................................................................................... 32
Contact .......................................................................................................................................................... 33
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MAX-8 / MAX-M8 - Hardware integration manual
eFuse
String
turn-off single-crystal feature
B5 62 06 41 09 00 01 01 92 81 E6 39 93 2B EE 30 31
1 Hardware description
1.1 Overview
u-blox MAX-8 / MAX-M8 modules are standard precision GNSS positioning modules featuring the
high-performance u-blox 8 / M8 positioning engine. Available in the industry standard MAX form
factor in a leadless chip carrier (LCC) package, they are easy to integrate and combine exceptional
positioning performance with highly flexible power, design, and connectivity options. SMT pads allow
fully automated assembly with standard pick and place and reflow-soldering equipment for costefficient, high-volume production enabling short time-to-market.
☞ For product features see the data sheet for MAX-8 [1] or MAX-M8 [2] .
☞ To determine which u-blox product best meets your needs, see the product selector tables on the
u-blox website www.u-blox.com.
1.2 Configuration
The configuration settings can be modified using UBX protocol configuration messages; see the ublox 8 / u-blox M8 Receiver Description including Protocol Specification [3]. The modified settings
remain effective until power-down or reset. If these settings have been stored in BBR (battery backed
RAM), the modified configuration will be retained as long as the backup battery supply (V_BCKP) is
not interrupted.
⚠ eFuse is one-time-programmable; it cannot be changed if it has been programmed once.
In order to save backup current, a u-blox MAX-8C / MAX-M8C module configured in “single crystal“
mode can have the single-crystal feature turned off by means of a SW command. Hot start
performance will be degraded (no time information at startup).
Use the string in Table 1 to turn off the single-crystal feature. This is recommended for low-power
applications, especially if time will be delivered by GSM or uC.
Table 1: String to turn off single-crystal feature
1.3 Connecting power
u-blox MAX-8 / MAX-M8 positioning modules have up to three power supply pins: VCC, VCC_IO, and
V_BCKP.
VCC: Main supply voltage
The VCC pin provides the main supply voltage. During operation, the current drawn by the module can
vary by some orders of magnitude, especially if enabling low-power operation modes. For this reason,
it is important that the supply circuitry be able to support the peak power for a short time (see the
data sheet for MAX-8 [1] or MAX-M8 [2] for specification).
☞ When switching from backup mode to normal operation or at start-up, u-blox MAX-8 / MAX-M8
modules must charge the internal capacitors in the core domain. In certain situations, this can
result in a significant current draw. For low-power applications using power save and backup
modes, it is important that the power supply or low ESR capacitors at the module input can deliver
this current/charge.
☞ Use a proper GND concept. Do not use any resistors or coils in the power line.
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1.3.1 VCC_IO: IO supply voltage
VCC_IO from the host system supplies the digital I/Os. The wide range of VCC_IO allows seamless
interfacing to standard logic voltage levels independent of the VCC voltage level. In many applications,
VCC_IO is simply connected to the main supply voltage.
☞ Without a VCC_IO supply, the system will remain in reset state.
1.3.2 V_BCKP: Backup supply voltage
If there is a power failure on the module supply (VCC_IO), the real-time clock (RTC) and battery backed
RAM (BBR) are supplied through the V_BCKP pin. Thus orbit information and time can be maintained
and will allow a hot or warm start. If no backup battery is connected, the module performs a cold start
at every power up if no aiding data are sent to the receiver
☞ Avoid high resistance on the V_BCKP line: During the switch from main supply to backup supply,
a short current adjustment peak can cause high voltage drop on the pin with possible
malfunctions.
☞ If no backup supply voltage is available, connect the V_BCKP pin to VCC_IO.
☞ As long as power is supplied to the u-blox 8 / M8 modules through the VCC_IO pin, the backup
battery is disconnected from the RTC and the BBR to avoid unnecessary battery drain (see Figure
1). In this case, VCC_IO supplies power to the RTC and BBR.
Figure 1: Backup battery and voltage (for exact pin orientation, see the data sheet for MAX-8 [1] or MAX-M8 [2] )
Single-crystal feature on MAX-8C / MAX-M8C
On MAX-8C / MAX-M8C, the reference frequency for the RTC clock will be internally derived from the
main clock frequency (26 MHz) when in backup mode (does not have a 32 kHz oscillator). This feature
is called “single-crystal” operation. In the event of a power failure, the backup battery at V_BCKP will
supply the 26 MHz crystal oscillator, as needed to maintain the time. This makes MAX-8C / MAX-M8C
a more cost-efficient solution at the expense of a higher backup current, as compared to other MAX8 / MAX-M8 variants that use an ordinary RTC crystal. Therefore, the capacity of the backup battery
at V_BCKP must be increased if hardware backup mode is needed (see the data sheet for MAX-8 [1]
or MAX-M8 [2] for specification).
If the battery used cannot provide the increased current consumption for the needed time on MAX8C / MAX-M8C, the “single-crystal” feature can be permanently disabled. The backup current will be
the same as on MAX-8 / MAX-M8 modules without the “single-crystal” feature. But the time
information is not maintained during off time. So the customer either aides the time to the receiver
at every startup, or the hot and warm start performance will be degraded because of missing time
information.
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Send this string to disable the “single-crystal” feature:
“B5 62 41 09 00 01 01 92 81 E6 39 93 2B EE 30 31”.
⚠ This string has to be sent once in production and will permanently turn off the single-crystal
feature on MAX-8C / MAX-M8C. The hot start and warm start performance will be degraded if time
information is not provided to the receiver at every startup.
1.3.3 VCC_RF: Output voltage RF
The VCC_RF pin can be used to supply an active antenna or an external LNA. For more information,
see section 2.4.
1.3.4 V_ANT: Antenna supply (MAX-M8W)
At V_ANT pin an antenna supply voltage can be connected which will be provided at RF_IN to supply
an active antenna. For more information see section 2.4.3.
☞ If not used, connect the V_ANT pin to GND.
1.4 Interfaces
1.4.1 UART
u-blox MAX-8 / MAX-M8 positioning modules include a Universal Asynchronous Receiver Transmitter
(UART) serial interface RXD/TXD that supports configurable baud rates. The UART output and input
levels are 0 V to VCC_IO. An interface based on RS232 standard levels (+/- 12 V) can be implemented
using level shifters such as Maxim MAX3232. Hardware handshake signals and synchronous
operation are not supported.
1.4.2 Display data channel (DDC)
An I2C-compatible display data channel (DDC) interface is available with u-blox MAX-8 / MAX-M8
modules for serial communication with an external host CPU. The interface only supports operation
in slave mode (master mode is not supported). The DDC protocol and electrical interface are fully
compatible with the fast-mode of the I2C industry standard. DDC pins SDA and SCL have internal
pull-up resistors to VCC_IO.
For more information about the DDC implementation, see the u-blox 8 / u-blox M8 Receiver
Description including Protocol Specification [3]. For bandwidth information, see the MAX-8 Data
sheet [1] and MAX-M8 Data sheet [2]. For timing, parameters consult the I2C-bus specification [6].
☞ The u-blox MAX-8 / MAX-M8 DDC interface supports serial communication with u-blox cellular
modules. See the specification of the applicable cellular module to confirm compatibility.
1.4.3 TX_READY
The TX_READY function is used to indicate when the receiver has data to transmit. A listener can wait
on the TX_READY signal instead of polling the DDC or SPI interfaces. The UBX-CFG-PRT message lets
you configure the polarity and the number of bytes in the buffer before the TX READY signal goes
active. The TX_READY function can be mapped to TXD (PIO 06). The TX_READY function is disabled
by default.
☞ The TX_READY functionality can be enabled and configured by AT commands sent to the u-blox
cellular module supporting the feature. For more information, see the GPS Implementation and
Aiding Features in u-blox wireless modules [7].
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1.5 I/O pins
All I/O pins make use of internal pull-ups. Thus, there is no need to connect unused pins to VCC_IO.
1.5.1 RESET_N: Reset input
Driving RESET_N low activates a hardware reset of the system. 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. In u-blox MAX-8 / MAX-M8 modules, RESET_N is an input only.
1.5.2 EXTINT: External interrupt
EXTINT is an external interrupt pin with fixed input voltage thresholds with respect to VCC_IO (see
the data sheet for MAX-8 [1] and MAX-M8 [2] for more information). It can be used for wake-up
functions in power save mode in all u-blox 8 / M8 modules and for aiding. Leave open if unused; the
functions are disabled by default.
If the EXTINT is not used for an external interrupt function, it can be used for some other purpose, for
example, as an output pin for the TX_READY feature to indicate that the receiver has data to
transmit.
Power control
The power control feature allows overriding the automatic active/inactive cycle of power save mode.
The state of the receiver can be controlled through the EXTINT pin. The receiver can also be forced
OFF using EXTINT when power save mode is not active.
Frequency aiding
The EXTINT pin can be used to supply time or frequency aiding data to the receiver.
For time aiding, hardware time synchronization can be achieved by connecting an accurate time pulse
to the EXTINT pin.
Frequency aiding can be implemented by connecting a periodic rectangular signal with a frequency up
to 500 kHz and an arbitrary duty cycle (low/high phase duration must not be shorter than 50 ns) to
the EXTINT pin. Provide the applied frequency value to the receiver using UBX messages.
1.5.3 SAFEBOOT_N
The SAFEBOOT_N pin is for future service, updates and reconfiguration.
1.5.4 TIMEPULSE
A configurable time pulse signal is available with all u-blox 8 / u-blox M8 modules. By default, the time
pulse signal is configured to 1 pulse per second. For more information, see the u-blox 8 / u-blox M8
Receiver Description including Protocol Specification [3].
1.5.5 LNA_EN: LNA enable
In the power save mode in MAX-M8Q, MAX-M8C, MAX-8C and MAX-8Q modules, the system can
turn on/off an optional external LNA using the LNA_EN signal to optimize power consumption.
Signals: "high" = Turn ON LNA, "low" = Turn OFF LNA
Antenna short circuit detection (ANT_OK) (MAX-M8W)
MAX-M8W module includes internal short circuit antenna detection. For more information, see
section 2.4.5.
"high" = Antenna is OK (e.g. no short)
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"low" = Antenna is not OK (e.g. short)
Antenna supervision is configurable using message UBX-CFG-ANT.
☞ Refer to the u-blox 8 / u-blox M8 Receiver Description including Protocol Specification [3] for
information about further settings.
1.5.6 ANT_DET: Open circuit detection (MAX-M8)
Antenna open circuit detection (ANT_DET) is not activated by default on the MAX-8 / MAX-M8
modules. ANT_DET can be mapped to PIO13 (EXTINT).
ANT_DET is an input used to report whether an external circuit has detected an external antenna or
not.
"high" = Antenna detected (antenna consumes current)
"low" = Antenna not detected (no current drawn)
Antenna supervision is configurable using message UBX-CFG-ANT.
☞ Refer to the u-blox 8 / u-blox M8 Receiver Description including Protocol Specification [3] for
information about further settings.
1.6 Electromagnetic interference on I/O lines
Any I/O signal line with a length greater than approximately 3 mm can act as an antenna and may pick
up arbitrary RF signals transferring them as noise into the GNSS receiver. This specifically applies to
unshielded lines, in which the corresponding GND layer is remote or missing entirely, and lines close
to the edges of the printed circuit board.
If, for example, a cellular signal radiates into an unshielded high-impedance line, it is possible to
generate noise in the order of volts and not only distort receiver operation but also damage it
permanently.
On the other hand, noise generated at the I/O pins will emit from unshielded I/O lines. Receiver
performance may be degraded when this noise is coupled into the GNSS antenna (see Figure 19).
To avoid interference by improperly shielded lines, it is recommended to use resistors (for example,
R>20 ), ferrite beads (for example, BLM15HD102SN1) or inductors (for example, LQG15HS47NJ02)
on the I/O lines in series. Choose these components with care because they also affect the signal rise
times.
Figure 2 shows an example of EMI protection measures on the RX/TX line using a ferrite bead. More
information can be found in section 4.3.
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Figure 2: EMI precautions
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Function
Pin
No.
I/O
Description
Remarks
Power
VCC 8 I
Supply voltage
Provide clean and stable supply.
GND
1,10,12
I
Ground
Assure a good GND connection to all GND pins of the module,
preferably with a large ground plane.
V_BCKP
6
I
Backup supply
voltage
Backup supply voltage input pin. Connect to VCC_IO if not
used.
Antenna
RF_IN
11
I
GNSS signal
input from
antenna
The connection to the antenna has to be routed on the PCB.
Use a controlled impedance of 50 to connect RF_IN to the
antenna or the antenna connector. DC block inside.
VCC_RF
14
O
Output voltage
RF section
Can be used for active antenna or external LNA supply.
LNA_EN
(MAX-M8C/Q
MAX-8C/Q)
Reserved
(MAX-M8W)
13
O
Active antenna
control
Ext. LNA control pin in power save mode.
LNA_EN pin voltage level is VCC_IO
-
Reserved
Leave open
UART
TXD
2 O Serial port
UART, leave open if not used, voltage level referred VCC_IO.
Can be configured as TX ready indication for the DDC
interface.
RXD 3 I
Serial port
UART, leave open if not used, voltage level referred VCC_IO
System
TIMEPULSE
4
O
Timepulse
signal
Leave open if not used, voltage level referred VCC_IO
PIO13/EXTINT
5
I
External
interrupt
Leave open if not used, voltage level referred VCC_IO.
Can be programmed on MAX-M8W as open circuit detection
(ANT_DET)
SDA
16
I/O
DDC pins
DDC data. Leave open, if not used.
SCL
17 I DDC pins
DDC clock. Leave open, if not used.
VCC_IO
7 I VCC_IO
IO supply voltage. Input must always be supplied. Usually
connect to VCC pin 8.
RESET_N
9 I Reset
Reset
V_ANT
(MAX-M8W )
Reserved
(MAX-M8C/Q
MAX-8C/Q)
15
I
Antenna bias
voltage
Connect to GND (or leave open) if passive antenna is used. If
an active antenna is used, add a 10 resistor in front of
V_ANT input to the antenna bias voltage or VCC_RF.
-
Reserved
Leave open
SAFEBOOT_N
18 I SAFEBOOT_N
For future service, leave open
No
Previous name
New name
13
ANT_ON
LNA_EN
2 Design
2.1 Pin description
Table 2: Pinout MAX-8 / MAX-M8
2.1.1 Pin name changes
Selected pin names have been updated to agree with the common naming convention across u-blox
modules. The pins have not changed their operation and are the same physical hardware but with
updated names. The table below lists the pins that have a changed name along with their old and new
names.
Table 3: Pin name changes
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9.7 mm [382 mil]
10.1 mm [
398
mil
]
1.0 mm
[39.3 mil]
0.7 mm
[
27.6
mil
]
0.8 mm
[31.5
mil
]
0.65 mm
[
26.6
mil
]
1.1 mm
[43.3
mil
]
0.8 mm
[
31.5
mil
]
Figure 4: MAX-8 / MAX-M8 footprint
Stencil: 150m
7.9 mm [311 mil]
12.5 mm [492 mil]
9.7 mm [382 mil]
0.7 mm
[27.6
mil
]
0.5 mm
[19.7
mil
]
0.8 mm
[31.5
mil
]
0.6 mm
[23.5
mil
]
Figure 5: MAX-8 / MAX-M8 paste mask
2.2 Minimal design
This is a minimal setup for a MAX-8 / M8 GNSS receiver:
Figure 3: MAX-8 / MAX-M8 passive antenna design
☞ For information on increasing immunity to jammers such as GSM, see section 4.3.
2.3 Layout: Footprint and paste mask
Figure 4 describes the footprint and provides recommendations for the paste mask for MAX-8 / MAXM8 LCC modules. 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 Tshape (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
customer’s specific production processes (for example, soldering).
.
☞ MAX form factor (10.1 x 9.7 x 2.5): same pitch as NEO for all pins: 1.1 mm, but 4 pads in each
corner (pin 1, 9, 10 and 18) only 0.7 mm wide instead of 0.8 mm.
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2.4 Antenna and antenna supervision
The MAX-8 / MAX-M8 modules are designed for use with an active antenna, see section 2.4.2.
2.4.1 Antenna design with passive antenna
☞ A passive antenna can be used, but it requires an external LNA and SAW for best performance.
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 .
Figure 6 shows a minimal setup for a design with a good GNSS patch antenna.
Figure 6: Module design with passive antenna (for exact pin orientation see data sheet for MAX-8 [1] and MAX-M8 [2])
☞ Use an antenna that has sufficient bandwidth to receive all GNSS constellations. See Error!
eference source not found..
Figure 7 shows a design using an external LNA and SAW to increase the sensitivity for best
performance with passive antenna.
Figure 7: MAX-8C/Q and M8C/Q module design with passive antenna and an external LNA and SAW (for exact pin orientation
see data sheet for MAX-8 [1] and MAX-M8 [2])
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The LNA_EN pin (LNA enable) can be used to turn on and off an optional external LNA in power save
mode in on/off operation.
The VCC_RF output can be used to supply the LNA with a filtered supply voltage.
☞ A standard GNSS LNA has enough bandwidth to amplify GPS/GLONASS/BeiDou signals.
Figure 8: MAX-M8W module design with passive antenna and an external LNA and SAW (for exact pin orientation see the
MAX-M8 Data sheet [2])
2.4.2 Antenna design with active antenna
Active antennas have an integrated low-noise amplifier. Active antennas require a power supply that
will contribute to the total budget of GNSS system power consumption, with typically an additional
5 to 20 mA.
If the supply voltage of the MAX-8 / M8 receivers matches the supply voltage of the antenna (for
example, 3.0 V), use the filtered supply voltage available at pin VCC_RF as shown in Figure 9.
Active antenna design using VCC_RF pin to supply the active antenna
Figure 9: MAX-8C/Q and M8C/Q active antenna design, external supply from VCC_RF (for exact pin orientation see data
sheet for MAX-8 [1] and MAX-M8 [2])
For the MAX-M8W active antenna design with external supply from VCC_RF, see Figure 11.
In case the VCC_RF voltage does not match with the supply voltage of the active antenna, use a
filtered external supply as shown in Figure 10.
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Active antenna design powered from external supply
Since the external bias voltage is fed into the most sensitive part of the receiver (RF input), this supply
should be free of noise. Usually, low frequency analog noise is less critical than digital noise of spurious
frequencies with harmonics up to the GNSS frequency.
Figure 10: MAX-8C/Q and M8C/Q active antenna design, direct external supply (for exact pin orientation see data sheet for
MAX-8 [1] and MAX-M8 [2])
☞ The circuit shown in Figure 10 works with all u-blox 8 / M8 modules, also with modules without
VCC_RF output.
External supply (MAX-M8W)
For the module design with active antenna with external supply, see Figure 13.
2.4.3 Antenna design with active antenna using antenna supervisor (MAX-
M8W)
An active antenna supervisor provides the means to check the antenna for open and short circuits
and to shut off the antenna supply if a short circuit is detected. The antenna supervisor is configured
using a serial port UBX binary protocol message. Once enabled, the active antenna supervisor
produces status messages, reporting in NMEA and/or UBX binary protocol (see section 2.4.4).
The current active antenna status can be determined by polling the UBX-MON-HW monitor
command. If an antenna is connected, the initial state after power-up is “Active Antenna OK.”
The module firmware supports an active antenna supervisor circuit, which is connected to the pin
EXTINT. For an example of an open circuit detection circuit, see Figure 14. High on EXTINT means
that an external antenna is not connected.
☞ Antenna open circuit detection (OCD) is not activated by default in the MAX-8/M8 modules. OCD
can be mapped to PIO13 (EXTINT). To activate the antenna supervisor, use the UBX-CFG-ANT
message. For more information about how to implement and configure OCD, see the u-blox 8 / ublox M8 Receiver Description including Protocol Specification [3].
☞ For recommended parts for the designs that follow, see the Appendix.
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Abbreviation
Description
AC
Active antenna control enabled
SD
Short circuit detection enabled
OD
Open circuit detection enabled
PDoS
Short circuit power down logic enabled
SR
Automatic recovery from short state
2.4.4 Status reporting
At startup, and on every change of the antenna supervisor configuration, the MAX-8/M8 modules will
output an NMEA ($GPTXT) or UBX (INF-NOTICE) message with the internal status of the antenna
supervisor (disabled, short detection only, enabled).
Table 4: Active antenna supervisor message on startup (UBX binary protocol)
☞ To activate the antenna supervisor use the UBX-CFG-ANT message. For further information, see
the u-blox 8 / u-blox M8 Receiver Description including Protocol Specification [3].
Similar to the antenna supervisor configuration, the status of the antenna supervisor will be reported
in an NMEA ($GPTXT) or UBX (INF-NOTICE) message at startup and on every change.
2.4.5 Power and short detection antenna supervisor (MAX-M8W)
If a suitably dimensioned series resistor R_BIAS is placed in front of pin V_ANT, a short circuit can be
detected in the antenna supply. This is detected inside the u-blox MAX-M8W module and the antenna
supply voltage will be immediately shut down. After this, periodic attempts to re-establish antenna
power are made by default.
An internal switch (under control of the receiver) can turn off the supply to the external antenna
whenever it is not needed. This feature helps to reduce power consumption in power save mode.
☞ To configure the antenna supervisor, use the UBX-CFG-ANT message. For further information,
see the u-blox 8 /u-blox M8 Receiver Description including Protocol Specification [3].
⚠ Short circuits on the antenna input without limitation (R_BIAS) of the current can result in
permanent damage to the receiver! Therefore, it is mandatory to implement an R_BIAS in all risk
applications, such as in situations where the antenna can be disconnected by the end-user, or
where long antenna cables are used.
☞ If VCC_RF voltage does not match with the antenna supply voltage, use a filtered external supply,
as shown in Figure 13.
Supply from VCC_RF (MAX-M8W)
Figure 11 shows an active antenna supplied from the u-blox MAX-M8W module.
The VCC_RF pin can be connected with V_ANT to supply the antenna. Note that the voltage
specification of the antenna has to match the actual supply voltage of the u-blox module (for example,
3.0 V).
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Figure 11: MAX-M8W module design with active antenna, internal supply from VCC_RF (for exact pin orientation, see the
MAX-M8 Data sheet [2])
The LNA_EN signal can be used to turn an external active antenna on and off. This reduces power
consumption in power save mode (backup mode).
Figure 12: External active antenna control (MAX-8C/Q and M8C/Q)
Figure 13: MAX-M8W module design with external supply, active antenna (for exact pin orientation, see the MAX-M8 Data sheet
[2])
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RFVcc
Rbias
RR
R
I _
32
2
2.4.6 Power, short and open detection antenna supervisor (MAX-M8W)
The open circuit detection (ANT_DET) circuit uses the current flow to detect an open circuit in the
antenna. Calculate the threshold current using Equation 1.
Figure 14: Schematic of open circuit detection (for exact pin orientation, see the MAX-M8 Data sheet [2])
Equation 1: Calculation of threshold current for open circuit detection
☞ Antenna open circuit detection (ANT_DET) is not activated by default. It can be enabled by the
UBX-CFG-ANT message. This configuration must be sent to the receiver at every startup.
To enable the antenna open circuit detection feature, the following command must be sent to the
receiver at every startup:
“B5 62 06 13 04 00 1F 00 F0 B5 E1 DE”.
"high" = Antenna detected (antenna consumes current)
"low" = Antenna not detected (no current drawn)
For more information about how to implement and configure OCD, see the u-blox 8 / u-blox M8
Receiver Description including Protocol Specification [3].
☞ If the antenna supply voltage is not derived from VCC_RF, do not exceed the maximum voltage
rating of ANT_DET.
2.5 Layout design-in: Thermal management
During design-in do not place the module near sources of heating or cooling. The receiver oscillator is
sensitive to sudden changes in ambient temperature which can adversely impact satellite signal
tracking. Sources can include co-located power devices, cooling fans or thermal conduction via the
PCB. Take into account the following questions when designing in the module.
Is the receiver placed away from heat sources?
Is the receiver placed away from air-cooling sources?
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Is the receiver shielded by a cover/case to prevent the effects of air currents and rapid
environmental temperature changes?
⚠ High temperature drift and air vents can affect the GNSS performance. For best performance,
avoid high temperature drift and air vents near the module.
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Pin
MAX-6
MAX-8/M8
Remarks for migration
Pin name
Typical assignment
Pin name
Typical assignment
1
GND
GND
GND
GND
No difference
2
TxD
Serial port
TXD
Serial port
No difference
3
RxD
Serial port
RXD
Serial port
No difference
4
TIMEPULSE
Timepulse (1PPS)
TIMEPULSE
Timepulse (1PPS)
No difference
5
EXTINT0
External interrupt pin
EXTINT
External interrupt pin
No difference
6
V_BCKP
Backup supply voltage
V_BCKP
Backup supply voltage
If this was connected to GND on ublox 6 module, it is OK to do the same
in u-blox 8 / M8.
(MAX-8C / M8C: Higher backup
current, see single crystal)
7
VCC_IO
IO supply voltage
Input must always be
supplied. Usually
connect to VCC pin 8.
VCC_IO
IO supply voltage input
must always be supplied.
Usually connect to VCC
pin 8.
No difference
8
VCC
Module power supply
MAX-6G 1.75 – 2.0 V
MAX-6Q/C: 2.7 – 3.6 V
VCC
Module power supply
MAX-8C/M8C: 1.65 – 3.6
V
MAX-8Q/M8Q: 2.7 – 3.6 V
9
VRESET
Connect to pin 8
RESET_N
Reset input
If pin 9 is connected directly to pin 8,
the RESET function is not available. If
the RESET function shall be used, a
3k3 resistor from pin 9 to pin 8 in
conjunction with an open drain buffer
is required for u-blox 6. For MAX-8 /
M8 modules, pin 8 can be connected
to pin 9 or can be left open. Do not
populate the 3k3 resistor.
Behavior of RESET_N has changed; in
u-blox 7 / 8 / M8, a RESET erases the
time information in the BBR, which
was maintained in u-blox 6. Therefore, in u-blox 7 / 8 / M8 a RESET will
not result in a hot start, etc.
10
GND
GND
GND
GND
No difference
3 Migration to u-blox 8 / M8 modules
3.1 Migrating u-blox 7 designs to u-blox 8 / 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 ensure there is no negative impact on
function or performance and to make u-blox 8 / M8 modules as fully compatible as possible with ublox 7 versions. If using BeiDou, check the bandwidth of the external RF components and the antenna.
For power consumption information, see the data sheet for MAX-8 [1] and MAX-M8 [2].
It is highly advisable that customers consider a design review with the u-blox support team to ensure
the compatibility of key functionalities.
☞ Selected pin names have been updated to agree with the common naming convention across u-
blox modules. The pins have not changed their operation and are the same physical hardware but
with updated names.
3.2 Hardware migration from MAX-6 to MAX-8 / M8
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Pin
MAX-6
MAX-8/M8
Remarks for migration
Pin name
Typical assignment
Pin name
Typical assignment
11
RF_IN
Matched RF-Input, DC
block inside.
RF_IN
Matched RF-Input, DC
block inside.
No difference
12
GND
GND
GND
GND
No difference
13
ANT_ON
Active antenna or ext.
LNA control pin in
power save mode.
ANT_ON pin voltage
level: MAX-6 ->
VCC_RF (pull-up)
LNA_EN
Ext. LNA control pin in
power save mode.
LNA_EN pin voltage level:
MAX-M8 -> VCC_IO
(push-pull)
On MAX-6, ANT_ON pin voltage level
is with respect to VCC_RF, on MAX8 / M8 to VCC_IO
(only relevant when VCC_IO does not
share the same supply with VCC)
14
VCC_RF
Can be used for active
antenna or external
LNA supply.
VCC_RF
Can be used for active
antenna or external LNA
supply.
No difference
15
RESERVED
Leave open.
RESERVED
(MAX-M8W:
V_ANT )
Leave open.
No difference
16
SDA
DDC data
SDA
DDC data
No difference
17
SCL
DDC clock
SCL
DDC clock
No difference
18
SAFEBOOT_N
Leave open.
SAFEBOOT_N
Leave open.
No difference
Table 5: Pin-out comparison MAX-6 vs. MAX-8 / MAX-M8
3.3 Software migration
☞ For an overall description of the module software operation, see the u-blox 8 / u-blox M8 Receiver
Description including Protocol Specification [3].
☞ For migration, see u-blox M8 FW SPG3.01 Migration Guide [8].
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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 data sheet for MAX-8 [1] and MAX-M8 [2].
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 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 2.3
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 be heated up
evenly, regardless of material properties, thickness of components and surface color.
Consider the IPC-7530 Guidelines for temperature profiling for mass soldering (reflow and wave)
processes, published 2001.
Preheat phase
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
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Peak reflow temperature: 245 ° C
Cooling phase
A controlled cooling avoids negative metallurgical effects of the solder (solder becomes more brittle)
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, place the u-blox 8 / M8 GNSS modules 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 baseboard, and so on. Exceeding the
maximum soldering temperature in the recommended soldering profile may permanently damage the
module.
Figure 15: Recommended soldering profile
☞ u-blox 8 / M8 modules must not be soldered with a damp heat process.
Optical inspection
After soldering the u-blox 8 / M8 modules, 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 be easily removed with a washing process.
Cleaning with water will lead to capillary effects where water is absorbed into 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.
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The best approach is to use a “no clean” soldering paste and eliminate the cleaning step after the
soldering.
Repeated reflow soldering
Only single reflow soldering processes are recommended for boards populated with u-blox 8 / M8
modules. To avoid upside down orientation during the second reflow cycle, u-blox 8 / M8 modules
should not be submitted to two reflow cycles on a board populated with components on both sides. In
such a case, the module should always be placed on the side of the board which is submitted into the
last reflow cycle. This is because of 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 8 / M8 modules.
Hand soldering
Hand soldering is allowed. Use a soldering iron temperature-setting equivalent to 350 °C. Place the
module precisely on the pads. Start with a cross-diagonal fixture soldering (for example, pins 1 and
15), and continue from left to right.
Rework
The u-blox 8 / 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, using a hot
air gun is not recommended 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, for example, 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. 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, be careful when 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 8 / M8 module before implementing this in the
production.
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☞ Casting will void the warranty.
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 8 / 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 8 / M8 module are sensitive to ultrasonic waves. Use of any ultrasonic
processes (cleaning, welding, and so on) may cause damage to the GNSS receiver.
☞ u-blox makes no warranty against damages to the u-blox 8 / M8 module caused by any ultrasonic
processes.
4.3 EOS/ESD/EMI precautions
When integrating GNSS positioning modules into wireless systems, consider electromagnetic and
voltage susceptibility issues carefully. Wireless systems include components, which 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, 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 the data sheet for MAX-8 [1] and MAX-M8 [2]).
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.
Exercise particular care when handling patch antennas, due to the risk of electrostatic charges. In
addition to standard ESD safety practices, take the following measures into account whenever
handling the receiver.
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Unless there is a galvanic coupling between the local GND
(i.e. the work table) and the PCB GND, 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.
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 a 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).
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
D
RF
_IN
GNSS
Receiver
LNA with appropriate ESD rating
⚠ 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.
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 where 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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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
EOS protection measures
☞ For designs with GNSS positioning modules and wireless (for example, cellular) 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 exceed, 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 (for example, cellular) and GNSS in the same design
or in close proximity.
Figure 17: EOS and ESD precautions
Electromagnetic interference (EMI)
Electromagnetic interference (EMI) is the addition or coupling of energy, which causes a spontaneous
reset of the GNSS receiver or results in unstable performance. In addition to EMI degradation due to
self-jamming (see section 1.5), any electronic device near the GNSS receiver can emit noise that can
lead to EMI disturbances or damage.
The following elements are critical regarding EMI:
Unshielded connectors (for example, pin rows)
Weakly shielded lines on PCB (for example, on top or bottom layer and especially at the border of a
PCB)
Weak GND concept (for example, 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 or, better yet, a ferrite bead or an
inductor (see Error! Reference source not found.) into any unshielded PCB lines connected to the
NSS receiver. Place the resistor as close to the GNSS receiver pin as possible.
Alternatively, feed-through capacitors with good GND connection can be used to protect, for example,
the VCC supply pin against EMI. A selection of feed-through capacitors is listed in Error! Reference
ource not found..
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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
Intended use
☞ To mitigate any performance degradation of a radio equipment under EMC disturbance, system
integration shall adopt appropriate EMC design practice and not contain cables over three meters
on signal and supply ports.
4.4 Applications with cellular modules
GSM terminals transmit power levels up to 2 W (+33 dBm) peak, 3G and LTE up to 250 mW
continuous. 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 [7].
Isolation between GNSS and cellular 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, for example, in the case of an integrated cellular
/GNSS antenna, an additional input filter is needed on the GNSS side to block the high energy emitted
by the cellular transmitter. Examples of these kinds of filters are the SAW Filters from Epcos (B9444
or B7839) or Murata.
Increasing interference immunity
Jamming signals come from in-band and out-band frequency sources.
In-band interference
With in-band jamming, the signal frequency is very close to the GNSS constellation frequency used,
for example, GPS frequency of 1575 MHz (see Figure 18). Such interference signals are typically
caused by harmonics from displays, micro-controller, bus systems.
Figure 18: In-band interference signals
Figure 19: In-band interference sources
Measures against in-band interference include:
Maintaining a good grounding concept in the design
Shielding
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Layout optimization
Filtering
Placement of the GNSS antenna
Adding a CDMA, GSM, WCDMA band pass filter before handset antenna
Out-band interference
Out-band interference is caused by signal frequencies that are different from the GNSS carrier (see
Figure 20). The main sources are wireless communication systems such as GSM, CDMA, WCDMA,
Wi-Fi, BT.
Figure 20: Out-band interference signals
Measures against out-band interference 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 21).
Figure 21: Measures against out-band interference
☞ For design-in recommendations in combination to cellular operation see Error! Reference source
ot found..
☞ See the GPS Implementation and Aiding Features in u-blox wireless modules [7].
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Abbreviation
Definition
ANSI
American National Standards Institute
BeiDou
Chinese navigation satellite system
CDMA
Code Division Multiple Access
EMC
Electromagnetic compatibility
EMI
Electromagnetic interference
EOS
Electrical Overstress
EPA
Electrostatic Protective Area
ESD
Electrostatic discharge
Galileo
European navigation system
GLONASS
Russian satellite system
GND
Ground
GNSS
Global Navigation Satellite System
GPS
Global Positioning System
GSM
Global System for Mobile Communications
IEC
International Electrotechnical Commission
PCB
Printed circuit board
QZSS
Quasi-Zenith Satellite System
Part
Manufacturer
Parts ID
Remarks
Parameters to consider
Diode
semiconductor
ON
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
B3913: B39162B3913U410
GPS+GLONASS+BeiDou
For automotive application
B4310: B39162B4310P810
GPS+GLONASS
Compliant to the AEC-Q200 standard
ReyConns
NDF9169
GPS+ BeiDou
Low insertion loss, only for mobile
application
Murata
SAFFB1G56KB0F0A
GPS+GLONASS+BeiDou
Low insertion loss, only for mobile
application
SAFEA1G58KB0F00
GPS+GLONASS
Low insertion loss, only for mobile
application
SAFEA1G58KA0F00
GPS+GLONASS
High attenuation, only for mobile
application
SAFFB1G58KA0F0A
GPS+GLONASS
High attenuation, only for mobile
application
Appendix
A Glossary
Table 6: Explanation of the abbreviations and terms used
B Recommended components
Recommended parts are selected on data sheet basis only. Other components may also be used.
UBX-15030059 - R06 Appendix Page 30 of 33
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MAX-8 / MAX-M8 - Hardware integration manual
Part
Manufacturer
Parts ID
Remarks
Parameters to consider
SAFFB1G58KB0F0A
GPS+GLONASS
Low insertion loss, only for mobile
application
TAI-SAW
TA1573A
GPS+GLONASS
Low insertion loss
TA1343A
GPS+GLONASS+BeiDou
Low insertion loss
TA0638A
GPS+GLONASS+BeiDou
Low insertion loss
LNA
JRC
NJG1143UA2
LNA
Low noise figure, up to 15 dBm RF
input power
Inductor
Murata
LQG15HS27NJ02
L, 27 nH
Impedance at freq. GPS > 500
Capacitor
Murata
GRM1555C1E470JZ01
C
DC-block
, 47 pF
DC-block
Murata
X7R 10N 10% 16 V
C
Bias
, 10nF
Bias-T
Ferrite
bead
Murata
BLM15HD102SN1
FB
High IZI at fGSM
Feedthrough
capacitor
for signal
Murata
NFL18SP157X1A3
Monolithic type
For data signals, 34 pF load
capacitance
NFA18SL307V1A45
Array Type
For data signals, 4 circuits in 1
package
Feedthrough
capacitor
Murata
NFM18PC ….
NFM21P….
0603 2A
0805 4A
Rs < 0.5
Resistor
10 10%, min 0.250 W
R
bias
560 5%
R2
100 k 5%
R3, R4
Manufacturer
Order no.
Comments
Hirschmann (www.hirschmann-car.com)
GLONASS 9 M
GPS+GLONASS active
Taoglas (www.taoglas.com)
AA.160.301111
36 x 36 x 4 mm, 3-5 V 30 mA active
Taoglas (www.taoglas.com)
AA.161.301111
36 x 36 x 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
35 x 35 x 3 mm GPS+GLONASS passive
Amotech (www.amotech.co.kr)
A25-4102920-2J3
25 x 25 x 4 mm GPS+GLONASS passive
Amotech (www.amotech.co.kr)
A18-4135920-AMT04
18 x 18 x 4 mm GPS+GLONASS passive
Amotech (www.amotech.co.kr)
AGA363913-S0-A1
GPS+GLONASS+BeiDou active
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
Table 7: Explanation of the abbreviations and terms used
Recommended antennas
Table 8: Recommended antennas
UBX-15030059 - R06 Appendix Page 31 of 33
Production Information
MAX-8 / MAX-M8 - Hardware integration manual
Revision
Date
Name
Comments
R01
16-May-2016
jfur
Advance Information
R02
08-Aug-2016
jfur
Production Information
R03
30-Jan-2017
mdur
Update Figure 14 and relevant content in section 2.4.6.
R04
06-Oct-2017
msul
Added information on RED DoC in European Union regulatory compliance
(page 2), added Intended use statement in section 0 Electromagnetic
interference (EMI), updated legal statement in cover page and added
Documentation feedback e-mail address in contacts page.
R05
07-Feb-2019
yzha
Clarified use of internal pull-ups in section 1.5. Clarified alternative uses for
the EXTINT pin in section 1.5.2.
R06
27-May-2020
mala
Added section 2.5 Layout design-in: Thermal management.
Minor editorial changes to reflect the latest style guide changes.
Related documents
[1] MAX-8 Data sheet, UBX-16000093
[2] MAX-M8 (FW3) Data sheet, UBX-15031506
[3] u-blox 8 / u-blox M8 Receiver Description including Protocol Specification (Public version), UBX-
13003221
[4] GPS Antenna Application Note, GPS-X-08014
[5] GPS Compendium, GPS-X-02007
[6] I2C-bus specification, Rev. 6 — 4 April 2014,
http://www.nxp.com/documents/user_manual/UM10204.pdf
[7] GPS Implementation and Aiding Features in u-blox wireless modules, GSM.G1-CS-09007
[8] u-blox M8 FW SPG3.01 Migration Guide, UBX-15028330
☞ For regular updates to u-blox documentation and to receive product change notifications, register
on our homepage (www.u-blox.com).
Revision history
UBX-15030059 - R06 Related documents Page 32 of 33
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