u-blox SAM-M8Q User Manual

Abstract

This document describes the hardware features and specifications of the SAM-M8Q patch antenna
module, which features the u-blox M8 concurrent GNSS engine with reception of GPS, GLONASS,
Galileo and QZSS signals.

www.u-blox.com

UBX-16018358 - R07

SAM-M8Q

Easy-to-use u-blox M8 GNSS antenna module

Hardware integration manual

SAM-M8Q - Hardware integration manual

Title

SAM-M8Q

Subtitle

Easy-to-use u-blox M8 GNSS antenna module

Document type

Hardware integration manual

Document number

UBX-16018358

Revision and date

R07

28-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

SAM-M8Q smart antenna module complies with all relevant requirements for RED 2014/53/EU. The SAM-M8Q 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

SAM-M8Q

SAM-M8Q-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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SAM-M8Q - Hardware integration manual

Contents

Document information ................................................................................................................................ 2

Contents .......................................................................................................................................................... 3

1 Hardware description ........................................................................................................................... 4

1.1 Overview ........................................................................................................................................................ 4

1.2 Configuration ............................................................................................................................................... 4

1.3 Connecting power ....................................................................................................................................... 4

1.4 Interfaces ...................................................................................................................................................... 5

1.4.1 UART ..................................................................................................................................................... 5

1.4.2 Display data channel (DDC) .............................................................................................................. 5

1.5 I/O pins ........................................................................................................................................................... 6

1.5.1 RESET_N: Reset .................................................................................................................................. 6

1.5.2 EXTINT: External interrupt ............................................................................................................... 6

1.5.3 TIMEPULSE.......................................................................................................................................... 6

1.5.4 SAFEBOOT_N ...................................................................................................................................... 7

1.6 Electromagnetic interference on I/O lines ............................................................................................. 7

2 Design ........................................................................................................................................................ 8

2.1 Pin description ............................................................................................................................................. 8

2.2 Minimal design............................................................................................................................................. 8

2.3 Footprint and paste mask ......................................................................................................................... 9

2.4 Antenna .......................................................................................................................................................10

2.5 Embedded antenna operation ................................................................................................................11

2.6 PCB layout suggestion .............................................................................................................................12

2.7 Layout design-in: Thermal management .............................................................................................12

3 Product handling ................................................................................................................................. 14

3.1 Packaging, shipping, storage and moisture preconditioning ..........................................................14

3.2 Soldering .....................................................................................................................................................14

3.3 EOS/ESD/EMI precautions ......................................................................................................................17

3.3.1 Electromagnetic interference (EMI) .............................................................................................18

3.4 Applications with cellular modules ........................................................................................................18

Appendix ....................................................................................................................................................... 21

A Glossary ................................................................................................................................................. 21

B Recommended parts ......................................................................................................................... 21

Related documents ................................................................................................................................... 22

Revision history .......................................................................................................................................... 22

Contact .......................................................................................................................................................... 23

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SAM-M8Q - Hardware integration manual

1 Hardware description

1.1 Overview

The SAM‑M8Q module is a concurrent GNSS patch antenna module featuring the high performance
u-blox M8 GNSS engine with reception of GPS, GLONASS, Galileo and QZSS signals. Available in an
LGA package, it is easy to integrate and combines 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 cost-efficient, high-volume production
enabling short time-to-market.

☞ For product features see the SAM-M8Q Data sheet [1].
☞ To determine which u-blox product best meets your needs, see the product selector tables on the

u-blox website (www.u-blox.com).

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 [2]. The modified settings
remain effective until power-down or reset. If these settings have been stored in battery-backed RAM
(BBR), the modified configuration will be retained, as long as the backup battery supply is not
interrupted.

1.3 Connecting power

The SAM‑M8Q antenna module has 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
SAM-M8Q Data sheet [1] for specification).

☞ When switching from backup mode to normal operation or at start-up, the SAM‑M8Q antenna

module must charge its 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 series resistors, ferrite beads or coils in the power line.
☞ The equipment must be supplied by an external limited power source in compliance with the clause

2.5 of the standard IEC 60950-1.

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.

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V_BCKP: Backup supply voltage

In case of a power failure on the module supply, V_BCKP supplies the real-time clock (RTC) and battery
backed RAM (BBR). Use of valid time and the GNSS orbit data at start-up improves the GNSS
performance, that is, hot starts and warm starts. If no backup battery is connected, the module
performs a cold start at power-up.

☞ 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 a supply is connected to VCC_IO of SAM‑M8Q antenna module, 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. V_BCKP supplies the RTC and BBR in case
VCC_IO voltage goes below 1.4V.

Figure 1: Backup battery and voltage

1.4 Interfaces

1.4.1 UART

The SAM‑M8Q antenna module includes a universal asynchronous receiver transmitter (UART) serial
interface, RxD/TxD, which supports configurable baud rates, as specified in the SAM-M8Q Data sheet
[1]. The signal output and input level is 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 SAM‑M8Q antenna 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 [2]. For bandwidth information, see the SAM-M8Q Data
sheet [1]. For timing parameters, consult the I2C-bus specification [6].

☞ The SAM-M8Q DDC interface supports serial communication with u-blox cellular modules. See the

specification of the applicable cellular module to confirm compatibility.

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TX_READY

The TX_READY function is used to indicate when the receiver has data to transmit on DDC interface.
A listener can wait on the TX_READY signal instead of polling the DDC 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].

1.5 I/O pins

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. The SAM-M8Q RESET_N pin is for input only.

☞ The RTC time is also reset (but not BBR). This means that the hot start performance will be

degraded after a reset.

☞ No additional capacitance should be added at RESET_N pin to GND (otherwise it could cause a

reset at startup).

1.5.2 EXTINT: External interrupt

EXTINT is an external interrupt pin with fixed input voltage thresholds with respect to VCC_IO (see

the SAM-M8Q Data sheet [1] for more information). It can be used for wake-up functions in power
save mode on and for aiding. Leave open if unused, function is disabled by default.

If EXTINT is not used for an external interrupt function, the pin can be used as a generic PIO (PIO13).
The PIO13 can be configured to function, for example, as an output pin for the TXD Ready feature to
indicate that the receiver has data to transmit. For further information, see u-blox 8 / u-blox M8
Receiver Description including Protocol Specification [2].

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 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 TIMEPULSE

A configurable time pulse signal is available with SAM‑M8Q antenna module. 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 [2]

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SAM-M8Q - Hardware integration manual

1.5.4 SAFEBOOT_N

The SAFEBOOT_N pin is for future service, updates and reconfiguration.

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 11).

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 RXD/TXD line using a ferrite bead. More
information can be found in section 3.3.

Figure 2: EMI precautions

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