Ublox NEO-M8N Quick setup guide

UBX-15029985 - R08
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NEO-8Q / NEO-M8
u-blox 8 / M8 GNSS modules
Hardware integration manual

Abstract
This document describes the features and specifications of u-blox NEO-8Q and NEO-
M8 series
modules.

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Document information
Title NEO-8Q / NEO-M8
Subtitle u-blox 8 / M8 GNSS modules
Document type Hardware integration manual
Document number UBX-15029985
Revision and date R08 5-May-2021
Document status Production information
Disclosure restriction C1-Public
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
NEO-8Q and NEO-M8J/N/M/Q/T modules comply with all relevant requirements for RED 2014/53/EU. The NEO-8Q and
NEO-M8J/N/M/Q/T Declaration of Conformity (DoC) is available at www.u-blox.com in Support > Product resources >
Conformity Declaration.
This document applies to the following products:
Product name Type number ROM/FLASH version PCN reference
NEO-M8N NEO-M8N-0-11 FLASH FW SPG 3.01 UBX-20013367
NEO-M8M NEO-M8M-0-11 ROM SPG 3.01 UBX-21015022
NEO-M8Q NEO-M8Q-0-11 ROM SPG 3.01 UBX-20013367
NEO-M8T NEO-M8T-0-11 FLASH FW3.01 TIM 1.10 UBX-20013367
NEO-8Q NEO-8Q-0-11 ROM SPG 3.01 UBX-20013367
NEO-M8J NEO-M8J-0-10 Flash FW SPG 3.05 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 provid
ed “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 doc
ument 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.

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Contents
Document information................................................................................................................................2
Contents ..........................................................................................................................................................3
1Hardware description...........................................................................................................................5
1.1 Overview........................................................................................................................................................ 5
1.2 Configuration ............................................................................................................................................... 5
1.3 Connecting power ....................................................................................................................................... 5
1.3.1 VCC: Main supply voltage .................................................................................................................5
1.3.2 V_BCKP: Backup supply voltage ...................................................................................................... 5
1.3.3 VDD_USB: USB interface power supply ......................................................................................... 6
1.3.4 VCC_RF: Output voltage RF ............................................................................................................. 6
1.4 Interfaces......................................................................................................................................................6
1.4.1 UART ..................................................................................................................................................... 6
1.4.2 USB ........................................................................................................................................................ 7
1.4.3 Display Data Channel (DDC) .............................................................................................................7
1.4.4 SPI .......................................................................................................................................................... 8
1.4.5 TX_READY............................................................................................................................................8
1.5 I/O pins...........................................................................................................................................................8
1.5.1 RESET_N: Reset..................................................................................................................................8
1.5.2 EXTINT: External interrupt ............................................................................................................... 8
1.5.3 SAFEBOOT_N ...................................................................................................................................... 9
1.5.4 D_SEL: Interface select .....................................................................................................................9
1.5.5TIMEPULSE (TIMEPULSE1 on NEO-M8T) .................................................................................... 9
1.5.6 TIMEPULSE2 ....................................................................................................................................... 9
1.5.7 LNA_EN: LNA enable.......................................................................................................................... 9
1.6 Electromagnetic interference on I/O lines ...........................................................................................10
2Design ..................................................................................................................................................... 11
2.1 Pin description ...........................................................................................................................................11
2.1.1 Pin name changes.............................................................................................................................12
2.2 Minimal design...........................................................................................................................................12
2.3 Layout: Footprint and paste mask ........................................................................................................12
2.4 Antenna.......................................................................................................................................................13
2.4.1 Antenna design with passive antenna .........................................................................................13
2.4.2 Active antenna design .....................................................................................................................15
2.5 Layout design-in: Thermal management.............................................................................................16
3Migration to u-blox 8 / M8 modules.............................................................................................. 17
3.1 Migrating u-blox 7 designs to NEO-8Q and NEO-M8 series modules............................................17
3.2 Hardware migration of NEO-6 to NEO-8Q and NEO-M8 series.......................................................17
3.3 Software migration...................................................................................................................................18
4Product handling................................................................................................................................. 19
4.1 Packaging, shipping, storage and moisture preconditioning ..........................................................19

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4.2 Soldering .....................................................................................................................................................19
4.3 EOS/ESD/EMI precautions......................................................................................................................22
4.4 Applications with cellular modules........................................................................................................25
Appendix ....................................................................................................................................................... 27
AGlossary ................................................................................................................................................. 27
BRecommended parts ......................................................................................................................... 27
Related documents ................................................................................................................................... 29
Revision history.......................................................................................................................................... 30
Contact.......................................................................................................................................................... 31

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1Hardware description
1.1 Overview
u-blox NEO-8Q, NEO-M8N, NEO-M8Q, NEO-M8M and NEO-M8J standard precision GNSS modules,
and the NEO-M8T timing GNSS module, all feature the high performance u-blox M8 GNSS engine.
Available in the industry standard NEO 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 & place and
reflow-soldering equipment for cost-efficient, high-volume production enabling short time-to-
market.
☞For product features, see the corresponding product data sheet in the Related documents section.
☞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 u-
blox 8 / u-blox M8 Receiver Description including Protocol Specification [4]. The modified settings
remain effective until power-down or reset. If these settings have been stored in BBR (Battery Backed
RAM), then the modified configuration will be retained, as long as the backup battery supply is not
interrupted.
For the NEO-M8N and NEO-M8J modules, configuration can be saved permanently in SQI flash.
1.3 Connecting power
The u-blox NEO-8Q and NEO-M8 series modules have three power supply pins: VCC, V_BCKP, and
VDD_USB.
1.3.1 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 (for the
specifications, see the corresponding product data sheet in the Related documents section).
☞When switching from backup mode to normal operation or at start-up, u-blox NEO-8Q and NEO-
M8 series 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.
1.3.2 V_BCKP: Backup supply voltage
If the module supply has a power failure, the V_BCKP pin supplies the real-time clock (RTC) and
battery backed RAM (BBR). Use of valid time and the GNSS orbit data at start up will improve the
GNSS performance, as with hot starts, warm starts, AssistNow Autonomous and AssistNow Offline.
If no backup battery is connected, the module performs a cold start at power up.

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Figure 1: Backup battery and voltage (for exact pin orientation, see the corresponding product data sheet)
☞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_BCKPpin to VCC.
☞As long as power is supplied to the NEO-8Q and NEO-M8 series modules through the VCC pin, the
backup battery is disconnected from the RTC and the BBR to avoid unnecessary battery drain (see
Figure 1). In this case, VCC supplies power to the RTC and BBR.
Real-Time Clock (RTC)
The RTC is driven by a 32 kHz oscillator using an RTC crystal. If the main supply voltage fails, and a
battery is connected to V_BCKP, parts of the receiver switch off, but the RTC still runs providing a
timing reference for the receiver. This operating mode is called Hardware Backup Mode, which enables
all relevant data to be saved in the backup RAM to allow a hot or warm start later.
1.3.3 VDD_USB: USB interface power supply
VDD_USB supplies the USB interface. If the USB interface is not used, the VDD_USB pin must be
connected to GND. For more information about correctly handling the VDD_USB pin, see section 1.4.
1.3.4 VCC_RF: Output voltage RF
The VCC_RF pin can supply an active antenna or external LNA. For more information, see section 2.4.
1.4 Interfaces
1.4.1 UART
The NEO-8Q and NEO-M8 series modules include a Universal Asynchronous Receiver Transmitter
(UART) serial interface RXD/TXD supporting configurable baud rates. The baud rates supported are
specified in the corresponding product data sheet.
The signal output and input levels are 0 V to VCC. 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.
☞Designs must allow access to the UART pin for future service and reconfiguration.

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1.4.2 USB
A USB version 2.0 FS (Full Speed, 12 Mbit/s) compatible interface is available for communication as
an alternative to the UART. The USB_DP integrates a pull-up resistor to signal a full-speed device to
the host. The VDD_USB pin supplies the USB interface.
u-blox provides Microsoft® certified USB drivers for Windows 7, Windows 8 and Windows 10
operating systems. These drivers are available at our website at www.u-blox.com
USB external components
The USB interface requires some external components to implement the physical characteristics
required by the USB 2.0 specification. These external components are shown in Figure 2 and listed in
Table 1. To comply with USB specifications, VBUS must be connected through an LDO (U1) to pin
VDD_USB on the module.
In USB self-powered mode, the power supply (VCC) can be turned off and the digital block is not
powered. In this case, since VBUS is still available, the USB host would still receive the 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 or the output of a voltage supervisor. 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 not connected, that
is, VBUS is not supplied.
☞USB bus-powered mode is not supported.
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 Ωis recommended.
R11 Resistor 100 kΩis recommended for USB self-powered setup.
Table 1: Summary of USB external components
1.4.3 Display Data Channel (DDC)
An I2C compatible Display Data Channel (DDC) interface is available on NEO-8Q and NEO-M8 series
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.

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For more information about the DDC implementation, see the u-blox 8 / u-blox M8 Receiver
Description Including Protocol Specification [4]. For bandwidth information, see the corresponding
product data sheet. For timing parameters, consult the I2C-bus specification [7].
☞The NEO-8Q and NEO-M8 series DDC interface supports serial communication with most u-blox
cellular modules. See the specification of the applicable cellular module to confirm compatibility.
1.4.4 SPI
An SPI interface is available for communication to a host CPU.
☞SPI is not available in the default configuration, because its pins are shared with the UART and
DDC interfaces. The SPI interface can be enabled by connecting D_SEL to ground. For speed and
clock frequency, see the corresponding product data sheet.
1.4.5 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 [8].
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
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. With NEO-8Q and NEO-M8 series modules RESET_N is an input only.
☞The RTC time is also reset (but not BBR).
1.5.2 EXTINT: External interrupt
EXTINT (EXTINT0 on NEO-M8T), PIO 13 is an external interrupt pin with fixed input voltage
thresholds with respect to VCC (see the corresponding product data sheet for more information). It
can be used for wake-up functions in power save mode on NEO-8Q and NEO-M8 series modules and
for aiding. Leave open if unused. The function is 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.
EXTINT1 is an external interrupt pin on NEO-M8T with fixed input voltage thresholds with respect to
VCC (see the corresponding product data sheet for more information). It can be used for wake-up
functions in Power Save Mode on NEO-M8T module and for aiding. Leave open if unused. The function
is disabled by default.

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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 (EXTINT0 on NEO-M8T) pin. The
receiver can also be forced OFF using EXTINT (EXTINT0 on NEO-M8T) when power save mode is not
active.
Frequency aiding
The EXTINT (EXTINT0 on NEO-M8T) 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 (EXTINT0 on NEO-M8T) pin.
Frequency aiding can be implemented by connecting a periodic rectangular signal with a frequency up
to 500 kHz and arbitrary duty cycle (low/high phase duration must not be shorter than 50 ns) to the
EXTINT (EXTINT0 on NEO-M8T) 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.
On the NEO-M8T module, a configurable TIMEPULSE2 signal can be programmed on
TP2/SAFEBOOT_N.
☞Do not pull low during reset.
1.5.4 D_SEL: Interface select
The D_SEL pin selects the available interfaces. SPI cannot be used simultaneously with UART/DDC. If
open, UART and DDC are available. If pulled low, the SPI interface is available. See the corresponding
product data sheet.
1.5.5 TIMEPULSE (TIMEPULSE1 on NEO-M8T)
On NEO-8Q and NEO-M8 series modules, a configurable time pulse signal is available. By default, the
time pulse signal is configured to one pulse per second. For more information, see the u-blox 8 / u-blox
M8 Receiver Description including Protocol Specification [4].
1.5.6 TIMEPULSE2
On the NEO-M8T module, a configurable TIMEPULSE2 signal can be programmed on
TP2/SAFEBOOT_N.
For more information, see the u-blox 8 / u-blox M8 Receiver Description including Protocol
Specification [4].
☞The TIMEPULSE2 output must not be held LOW during start-up.
1.5.7 LNA_EN: LNA enable
On NEO-M8N, NEO-M8J, NEO-M8Q, NEO-M8T and NEO-8Q modules, in power save mode, the
system can turn on/off an optional external LNA using the LNA_EN signal in order to optimize power
consumption.
Signals: "high" = Turn ON LNA, "low" = Turn OFF LNA

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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 15).
To avoid interference by improperly shielded lines, it is recommended to use resistors (e.g. R>20 Ω),
ferrite beads (e.g. BLM15HD102SN1) or inductors (e.g. LQG15HS47NJ02) on the I/O lines in series.
These components should be chosen with care because they will also affect the signal rise times.
Figure 3 shows an example of EMI protection measures on the RXD/TXD line using a ferrite bead. For
more information, see section 4.3.
Figure 3: EMI precautions

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2Design
2.1 Pin description
Function Pin No.I/O Description Remarks
Power VCC 23 Supply voltage Provide clean and stable supply.
GND 10,
12,
13, 24
Ground Assure a good GND connection to all GND pins of the module,
preferably with a large ground plane.
V_BCKP 22 Backup supply
voltage
It is recommended to connect a backup supply voltage to
V_BCKP in order to enable warm and hot start features on the
positioning modules. Otherwise, connect to VCC.
VDD_USB 7 USB power
supply
To use the USB interface, connect this pin to 3.0 – 3.6 V.
If no USB serial port used connect to GND.
Antenna RF_IN 11 I GNSS signal
input from
antenna
The connection to the antenna must be routed on the PCB.
Use a controlled impedance of 50 Ωto connect RF_IN to the
antenna or the antenna connector.
VCC_RF 9 O Output voltage
RF section
VCC_RF can be used to power an external active antenna.
UART TXD / SPI MISO
20 O UART_TX/ SPI
MISO
Communication interface,
can be programmed as TX_READY for DDC interface.
If pin 2 low => SPI MISO.
RXD / SPI MOSI 21 I UART_RX / SPI
MOSI
Serial input. Internal pull-up resistor to VCC. Leave open if not
used. If pin 2 low => SPI MOSI.
USB USB_DM 5 I/O USB I/O line USB bidirectional communication pin. Leave open if unused.
USB_DP 6 I/O USB I/O line
System TIMEPULSE
TIMEPULSE1
(NEO-M8T)
3 O Timepulse
signal
Configurable Timepulse signal (one pulse per second by
default). Leave open if not used.
SAFEBOOT_N
TP2 /
SAFEBOOT_N
(NEO-M8T)
1 I SAFEBOOT_N SAFEBOOT_N, leave OPEN
I/O TP2 /
SAFEBOOT_N
Configurable Timepulse2 signal
SAFEBOOT_N, leave open if not used. Do not pull low during
reset.
EXTINT 4 I External
interrupt
External interrupt pin.
Internal pull-up resistor to VCC. Leave open if not used.
Function is disabled by default.
EXTINT0
(NEO-M8T)
RESERVED
EXTINT1
(NEO-M8T)
15 - Reserved Leave open.
I External
interrupt
External interrupt pin.
Internal pull-up resistor to VCC. Leave open if not used.
Function is disabled by default.
SDA / SPI CS_N 18 I/O DDC data / SPI
CS_N
DDC data.
If pin 2 low => SPI chip select.
SCL / SPI CLK 19 I DDC Clock / SPI
SCK
DDC Clock.
If pin 2 low => SPI clock.
LNA_EN 14 O LNA_EN Antenna control can be used to turn on and off an optional
external LNA.
RESERVED
(NEO-M8M)
- Reserved Leave open.
RESET_N 8 I Reset input Reset input
D_SEL 2 I Selects the
interface
Allow selecting UART/DDC or SPI
open-> UART/DDC; low->SPI
RESERVED 16, 17 - Reserved Leave open.
Table 2: NEO-8Q and NEO-M8 series pinout

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2.1.1 Pin name changes
Selected pin names have been updated to agree with a 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.
No.Previous name New name
14 ANT_ON LNA_EN
20 TxD
SPI MISO
TXD /
SPI MISO
21 RxD
SPI MOSI
RXD /
SPI MOSI
Table 3: Pin name changes
2.2 Minimal design
This is a minimal design for a NEO-8Q and NEO-M8 series GNSS receiver.
Figure 4: NEO-8Q / NEO-M8 passive antenna design
☞NEO-M8M can support passive antenna, but for optimal operation it requires an external SAW and
LNA, see Figure 7.
2.3 Layout: Footprint and paste mask
Figure 5 describes the footprint of the NEO-8Q and NEO-M8 series modules and provides
recommendations (not specifications) for the paste mask 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.

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☞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.
St e n ci l : 150 µ m
10.4 mm [409.5 mil]
14.6 mm [575 mil]
12.2 mm [480 mil]
0.8 mm
[31.5 mil]
0.6 mm
[23.5 mil]
2.4 Antenna
2.4.1 Antenna design with passive antenna
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, care should be taken 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.
☞Use an antenna that has sufficient bandwidth to receive all GNSS constellations. See the
Appendix.
Figure 6 shows a minimal setup for a design with a good GNSS patch antenna. For exact pin
orientation, see the corresponding product data sheet.
Figure 6: NEO-M8N/J/T/Q and NEO-8Q passive antenna design
Figure 7 and Figure 8 show designs using an external LNA and SAW to increase the sensitivity for
optimum performance with passive antenna. For exact pin orientation, see the corresponding product
data sheet.
Figure
5: NEO-8Q and NEO-M8 series paste mask NEO-8Q and NEO-M8 series footprint
12.2 mm [480.3 mil]
16.0 mm [630 mil]
1.0 mm
[39.3 mil]
0.8 mm
[31.5 mil]
0.8 mm
[31.5 mil]
3.0 mm
[118.1 mil]
1.0 mm
[39.3 mil]
1.1 mm
[43.3 mil]

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Figure 7: NEO-M8M module design with passive antenna, external LNA and SAW filter
The VCC_RF output can be used to supply the LNA with a filtered supply voltage.
☞An external LNA is only required if the antenna is far away. In that case, the LNA must be placed
close to the passive antenna.
Figure 8: NEO-M8N/J/T/Q and NEO-8Q module design with passive antenna and an external LNA
The LNA_EN pin (LNA enable) can be used to turn on and off an optional external LNA.
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/Galileo/BeiDou signals.
☞An external LNA is only required if the antenna is far away. In that case the LNA must be placed
close to the passive antenna.

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2.4.2 Active antenna design
Active antennas have an integrated low-noise amplifier. Active antennas require a power supply that
will contribute to the total GNSS system power consumption budget with additional 5 to 20 mA
typically.
For maximum external gain see the corresponding product data sheet.
If the supply voltage of the NEO-8Q / NEO-M8 receiver matches the supply voltage of the antenna
(e.g. 3.0 V), use the filtered supply voltage available at pin VCC_RF as shown in Figure 9. For exact pin
orientation, see the corresponding product data sheet.
Active antenna design using VCC_RF pin to supply the active antenna
Figure 9: Active antenna design, external supply from VCC_RF
If the VCC_RF voltage does not match the supply voltage of the active antenna, use a filtered external
supply, as shown in Figure 10. For the exact pin orientation, see the corresponding product data sheet.
Active antenna design powered from external supply
Figure 10: Active antenna design, direct external supply
☞The circuit shown in Figure 10 works with all u-blox M8 modules, and with modules without
VCC_RF output.

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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.
Consider 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?
•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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3Migration to u-blox 8 / M8 modules
3.1 Migrating u-blox 7 designs to NEO-8Q and NEO-M8 series
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 NEO-8Q and NEO-M8 series modules as fully compatible as
possible with u-blox 7 modules. If using BeiDou, check the bandwidth of the external RF components
and the antenna. For information about power consumption, see the corresponding product data
sheet.
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 a 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 of NEO-6 to NEO-8Q and NEO-M8
series
Pin
NEO-6 NEO-8Q and NEO-M8 series Remarks for migration
Pin name Typical
assignment
Pin name Typical
assignment
1 SAFEBOOT_N Leave open SAFEBOOT_N Leave open No difference
2 SS_N SPI slave
select
D_SEL Selects the
interface
-> Various functions, compatible only when not
using SPI for communication.
3 TIMEPULSE 1 Timepulse 1
(1PPS)
TIMEPULSE/
TIMEPULSE1
Timepulse1 No difference
4 EXTINT0 External
interrupt pin
EXTINT/
EXTINT0
External interrupt No difference
5 USB_DM USB data USB_DM USB data No difference
6 USB_DP USB data USB_DP USB data No difference
7 VDD_USB USB supply VDD_USB USB supply No difference
8 RESERVED Pin 8 and 9
must be
connected
RESET_N Reset If pin 8 is connected directly to pin 9, the
RESET_N function is not available. If the
RESET_N function shall be used, a 3k3 resistor
from pin 8 to pin 9 in conjunction with an open
drain buffer is required for u-blox 6. For NEO-8Q /
NEO-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; For u-blox 7
and M8, a RESET_N will erase the time
information in the BBR, which was maintained in
u-blox 6. Therefore, with u-blox 7 and M8 a
RESET_N will not result in a hot start, etc.
9 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
10 GND GND GND GND No difference

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Pin
NEO-6 NEO-8Q and NEO-M8 series Remarks for migration
Pin name Typical
assignment
Pin name Typical
assignment
11 RF_IN GNSS signal
input
RF_IN GNSS signal input No difference
12 GND GND GND GND No difference
13 GND GND GND GND No difference
14 MOSI/
CFG_COM0
SPI MOSI /
configuration
pin.
Leave open if
not used.
LNA_EN Used to turn an
optional external
LNA on and off
LNA_EN (Active Antenna Control) can be used to
turn an optional external LNA on and off.
-> Different functions, no SPI MOSI and
configuration pins with NEO-8Q / NEO-M8. If not
used as default configuration, it must be set
using software command!
It is not possible to migrate from NEO-6 to NEO-
8Q / NEO-M8 if NEO-6 pin 14 is connected to
GND. In this case, migrate to NEO-M8M!
15 MISO/
CFG_COM1
SPI MISO /
configuration
pin. Leave
open if not
used.
RESERVED Leave open
16 CFG_GPS0/
SCK
Power mode
configuration
pin / SPI
clock. Leave
open if not
used.
RESERVED Leave open
17 RESERVED Leave open RESERVED Leave open No difference
18 SDA DDC data SDA DDC data / SPI
CS_N
No difference for DDC. If pin 2 low = SPI chip
select
19 SCL DDC clock SCL DDC clock / SPI
SCK
No difference for DDC. If pin 2 low = SPI clock
20 TxD Serial port TXD UART_TX / SPI
MISO
No difference for UART. If pin 2 low = SPI MISO
21 RxD Serial port RXD UART_RX / SPI
MOSI
No difference for UART. If pin 2 low = SPI MOSI
22 V_BCKP Backup
supply
voltage
V_BCKP Backup supply
voltage
Check current in Data sheet.
If in u-blox 6 module this was connected to GND,
you can do the same in u-blox M8/8.
23 VCC Supply
voltage
NEO-6Q /
M/P/V/T:
2.7 – 3.6 V
NEO-6G:
1.75 – 1.95 V
VCC Supply voltage
NEO-8Q /
NEO-M8N/Q/J:
2.7 – 3.6 V
NEO-M8M:
1.65 – 3.6 V
No difference for NEO-8Q / NEO-M8J/N/Q
Extended supply voltage range for NEO-M8M
24 GND GND GND GND No difference
Table 4: Pin-out comparison NEO-6 vs. NEO-8Q and NEO-M8 series
Make sure that the RF path (antenna and filtering) matches that of the GNSS constellations used.
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 [4].
☞For migration, see the u-blox M8 FW SPG3.01 Migration Guide [9].

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4Product 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 corresponding product data sheet.
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 highly recommended, as it does not require cleaning after the
soldering process. 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 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

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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 module 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. Exceeding the maximum
soldering temperature in the recommended soldering profile may permanently damage the module.
Figure 11: Recommended soldering profile
☞u-blox modules must not be soldered with a damp heat process.
Optical inspection
After soldering the u-blox 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 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.
The best approach is to use a “no clean” soldering paste and eliminate the cleaning step after the
soldering.