Ublox ZOE-M8 Series Quick setup guide

ZOE-M8 series
Ultra-small u-blox M8 SiP modules
Hardware integration manual
Abstract
This document describes the hardware features and specifications of the u-blox ZOE-M8G and
ZOE-M8Q GNSS SiP (system in package) modules.
www.u-blox.com
UBX-16030136 - R09

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Production information Document information
Document information
Title
ZOE-M8 series
Subtitle
Ultra-small u-blox M8 SiP modules
Document type
Hardware integration manual
Document number
UBX-16030136
Revision and date
R09
4-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
ZOE-M8G and ZOE-M8Q SiPs comply with all relevant requirements for RED 2014/53/EU. The ZOE-M8G/Q Declaration of
Conformity (DoC) is available at www.u-blox.com under Support > Product resources > Conformity Declaration.
This document applies to the following products:
Product name
Type number
ROM/FLASH version
PCN reference
ZOE-M8G
ZOE-M8G-0-10
ROM SPG 3.01 / Flash FW SPG 3.01
N/A
ZOE-M8Q
ZOE-M8Q-0-10
ROM SPG 3.01 / Flash FW 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.

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Contents
Document information................................................................................................................................2
Contents ..........................................................................................................................................................3
1Hardware description...........................................................................................................................5
1.1 Overview........................................................................................................................................................ 5
2Design-in...................................................................................................................................................6
2.1 Power management ...................................................................................................................................6
2.1.1 Main supply voltage (VCC)................................................................................................................ 6
2.1.2 V_CORE (only on ZOE-M8Q).............................................................................................................6
2.1.3 DC/DC converter (only on ZOE-M8Q) ............................................................................................. 6
2.1.4 Backup power supply (V_BCKP)....................................................................................................... 7
2.2 Interfaces......................................................................................................................................................8
2.2.1 UART interface....................................................................................................................................8
2.2.2 Display data channel (DDC) interface.............................................................................................8
2.2.3 SPI interface ........................................................................................................................................9
2.2.4 SQI interface ........................................................................................................................................9
2.3 I/O pins.........................................................................................................................................................10
2.3.1 Time pulse ..........................................................................................................................................10
2.3.2 External interrupt .............................................................................................................................10
2.3.3 External LNA enable.........................................................................................................................10
2.3.4 Electromagnetic interference and I/O lines.................................................................................10
2.4 Real-time clock (RTC)...............................................................................................................................11
2.4.1 RTC using a crystal...........................................................................................................................11
2.4.2 RTC using an external clock ...........................................................................................................11
2.4.3 Time aiding.........................................................................................................................................11
2.5 RF input.......................................................................................................................................................12
2.5.1 Passive antenna................................................................................................................................12
2.5.2 Improved jamming immunity .........................................................................................................13
2.5.3 Active antenna ..................................................................................................................................13
2.6 Safe boot mode (SAFEBOOT_N)............................................................................................................14
2.7 System reset (RESET_N) ........................................................................................................................14
2.8 Pin description ...........................................................................................................................................14
2.9 Typical schematic .....................................................................................................................................17
2.10 Design-in checklist....................................................................................................................................18
2.10.1 General considerations....................................................................................................................18
2.10.2 Schematic design-in for ZOE-M8 GNSS SiPs.............................................................................18
2.11 Layout design-in checklist ......................................................................................................................19
2.12 Layout..........................................................................................................................................................19
2.12.1 Footprint.............................................................................................................................................20
2.12.2 Paste mask ........................................................................................................................................20
2.12.3 Placement ..........................................................................................................................................20

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2.13 Layout design-in: Thermal management.............................................................................................20
2.14 EOS/ESD/EMI precautions......................................................................................................................21
2.14.1 Electrostatic discharge (ESD)........................................................................................................21
2.14.2 ESD protection measures ...............................................................................................................21
2.14.3 Electrical overstress (EOS) .............................................................................................................21
2.14.4 EOS protection measures...............................................................................................................22
2.14.5 Electromagnetic interference (EMI) .............................................................................................22
2.14.6 Applications with cellular modules ...............................................................................................23
3Product handling and soldering ..................................................................................................... 25
3.1 Packaging, shipping, storage and moisture preconditioning ..........................................................25
3.2 ESD handling precautions.......................................................................................................................25
3.3 Safety precautions ...................................................................................................................................25
3.4 Soldering .....................................................................................................................................................26
3.4.1 Soldering paste .................................................................................................................................26
3.4.2 Reflow soldering................................................................................................................................26
3.4.3 Optical inspection.............................................................................................................................26
3.4.4 Repeated reflow soldering ..............................................................................................................26
3.4.5 Wave soldering ..................................................................................................................................26
3.4.6 Rework ................................................................................................................................................26
3.4.7 Use of ultrasonic processes ...........................................................................................................26
4Product testing ................................................................................................................................... 27
4.1 Test parameters for the OEM manufacturer......................................................................................27
4.2 System sensitivity test............................................................................................................................27
4.2.1 Guidelines for sensitivity tests ......................................................................................................27
4.2.2 ‘Go/No go’ tests for integrated devices........................................................................................27
Appendix ....................................................................................................................................................... 28
AComponent selection ........................................................................................................................ 28
A.1 External RTC (Y1)......................................................................................................................................28
A.2 RF band-pass filter (F1)...........................................................................................................................28
A.3 Optional SQI flash (U3).............................................................................................................................29
A.4 Inductor for the DC/DC converter (L1)..................................................................................................29
A.5 External LNA (U1) .....................................................................................................................................30
A.6 RF ESD protection diode..........................................................................................................................30
A.7 Ferrite beads (FB1) ...................................................................................................................................30
A.8 Feed-through capacitors.........................................................................................................................30
A.9 Standard capacitors.................................................................................................................................30
BGlossary ................................................................................................................................................. 31
Related documents ................................................................................................................................... 32
Revision history.......................................................................................................................................... 33
Contact.......................................................................................................................................................... 34

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1Hardware description
1.1 Overview
u-blox ZOE-M8 standard precision GNSS SiP (system in package) modules feature the high
performance u-blox M8 GNSS engine. ZOE-M8’s ultra-miniature form factor integrates a complete
GNSS receiver including SAW filter, LNA and TCXO.
The ZOE-M8 SiPs are targeted for applications that require a small size without compromising the
performance. For RF optimization, the ZOE-M8 SiPs integrate a front-end SAW filter and an
additional front-end LNA for increased jamming immunity and easier antenna integration. A passive
antenna can be used to provide a highly integrated system solution with a minimal eBOM.
The ZOE-M8 SiPs can be easily integrated in manufacturing thanks to the advanced S-LGA (soldered
land grid array) packaging technology, which enables easier and more reliable soldering processes
compared to a normal LGA (land grid Array) package.
☞For product features, see the ZOE-M8 Data sheet [1].
☞To determine which u-blox product best meets your needs, see the product selector tables on the
u-blox website www.u-blox.com.

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2Design-in
To obtain good performance with ZOE-M8 GNSS receiver SiPs, there are a number of issues requiring
careful attention during the design-in. These include:
Power supply: Good performance requires a clean and stable power supply.
Interfaces: Ensure correct wiring, rate and message setup on the SiP and your host system.
Antenna interface: For optimal performance, seek short routing, matched impedance and no
stubs.
2.1 Power management
The ZOE-M8G is a 1.8 V variant, while the ZOE-M8Q is a 3.0 V variant and has an option to make use
of the built-in DC/DC converter to reduce the power consumption.
The ZOE-M8 GNSS SiPs provide two supply pins: VCC and V_BCKP. They can be supplied
independently or tied together, depending on the intended application.
Additionally, ZOE-M8Q has the option to make use of a built-in DC/DC converter and thus comes with
two additional supply pins, V_CORE and V_DCDC_OUT. The supply voltages are explained in the
following subsections.
2.1.1 Main supply voltage (VCC)
During operation, the ZOE-M8 GNSS SiPs are supplied through the VCC pin. Built-in LDOs generate
stabilized voltages for the core and RF domains of the chip, respectively. The current at VCC depends
heavily on the current state of the system and is in general very dynamic.
☞Do not add any series resistance (< 0.1 Ω) to the VCC supply, as it will generate input voltage noise
due to the dynamic current conditions.
The digital I/Os of the ZOE-M8 GNSS SiPs are also referred and supplied to the VCC voltage.
2.1.2 V_CORE (only on ZOE-M8Q)
V_CORE draws the main current of the ZOE-M8Q. The current at V_CORE depends heavily on the
current system state and in general exhibits very dynamic behavior. It can be supplied either by main
supply or with the built-in DC/DC converter, see section 2.1.3.
☞Do not add any series resistance greater than 0.1 Ωto the V_CORE supply as it will generate input
voltage noise due to the dynamic current conditions.
☞If a DC/DC converter is not used, supply V_CORE with the same supply as used for the VCC.
2.1.3 DC/DC converter (only on ZOE-M8Q)
ZOE-M8Q comes with a built-in DC/DC converter to supply V_CORE, thus enabling significant power
savings. For more information, see the ZOE-M8 Data sheet [1]. It requires an external inductor (L1)
and capacitor (C1). For the recommended inductor and capacitor, see Appendix A.4 and Appendix A.9.

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Figure 1 : Circuit for DC/DC converter with ZOE-M8Q
The DC/DC converter block provides an energy conversion efficiency of up to 85%. The actual value
depends on the current drawn and which external inductor (L1) and capacitor (C1) are used.
To enable the DC/DC converter there are two options.
Option 1: In production, send a one-time command to the ZOE-M8Q, which enables the DC/DC
converter permanently in ZOE-M8Q’s internal OTP memory. The command to be sent is “B5 62 06 41
0C 00 00 00 03 1F C5 90 E1 9F FF FF FE FF 45 79” and it will be acknowledged (UBX-ACK). After doing
a reset, it can be verified by checking the UBX-MON-LLC message.
☞Ensure a stable VCC supply when sending the command to enable the DC/DC converter.
Option 2: Alternatively, if no SQI flash is used, the DC/DC converter can be enabled by defining the SQI
flash pins as shown in Table 1.
Pin #
Name
State
Remarks
D1
SQI_D0
Open
Must be left open!
C1
SQI_D1
GND
Must be connected to GND!
E3
SQI_D2
GND
Must be connected to GND!
F3
SQI_D3
Open
Must be left open!
E1
SQI_CLK
GND
Must be connected to GND!
D3
SQI_CS_N
GND
Must be connected to GND!
Table 1: Enable DC/DC converter
☞If the SQI flash pins are used to enable the DC/DC converter, ensure that the SQI flash pins are set
exactly as mentioned in Table 1, otherwise it can cause malfunction of the ZOE-M8Q.
2.1.4 Backup power supply (V_BCKP)
In the case of a power failure at main supply VCC, the backup domain and optional RTC oscillator are
supplied by V_BCKP. Providing a V_BCKP supply maintains the time (RTC) and the GNSS orbit data
in the backup RAM. This ensures that any subsequent re-starts after a VCC power failure will benefit
from the stored data, providing a faster TTFF.
The GNSS satellite ephemeris data is typically valid for up to 4 hours. To enable hot starts, ensure
that the battery or capacitor at V_BCKP is able to supply the backup current for at least 4 hours. For
warm starts or when using the AssistNow Autonomous, the V_BCKP source must be able to supply
current for up to a few days.
☞If no backup supply is available, V_BCKP can be connected to the reserved neighbor pin G9.
☞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.
☞For description of the different power operating modes, see the ZOE-M8 Data sheet [1].

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2.2 Interfaces
The ZOE-M8 GNSS SiPs provide UART, SPI and DDC (I2C-compatible) interfaces for communication
with a host CPU. Additionally, an SQI interface is available for connecting the ZOE-M8 GNSS SiPs with
an optional external flash memory.
The UART, SPI and DDC pins are supplied by VCC and operate at this voltage level.
Four dedicated pins can be configured as either 1 x UART and 1 x DDC or a single SPI interface
selectable by the D_SEL pin. Table 2 below provides the port mapping details.
Pin #
Pin D4 (D_SEL) = “high” (left open)
Pin D4 (D_SEL) = “Low” (connected to GND)
J5
UART TXD
SPI MISO
J4
UART RXD
SPI MOSI
B1
DDC SCL
SPI CLK
A2
DDC SDA
SPI CS_N
Table 2: Communication interfaces overview
☞It is not possible to use the SPI interface simultaneously with the DDC or UART interface.
☞For debugging purposes, it is recommended to have a second interface, for example, DDC available
that is independent from the application and accessible via test-points.
For each interface, define a dedicated pin to indicate that data is ready to be transmitted. The TXD
Ready signal indicates that the receiver has data to transmit. Each TXD Ready signal is associated
with a particular interface and cannot be shared. A listener can wait on the TXD 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 TXD Ready signal goes active. The TX Ready signal can
be mapped, for example, to UART TX. The TXD Ready function is disabled by default.
☞The TXD Ready functionality can be enabled and configured by using suitable AT commands sent
to the u-blox cellular module in question that supports the feature. For more information, see the
GPS Implementation and Aiding Features in u-blox wireless modules [5].
☞The TXD Ready feature is supported on several u-blox cellular module products.
2.2.1 UART interface
A UART interface is available for serial communication to a host CPU. The UART interface supports
configurable data rates with the default at 9600 baud. Signal levels are related to the VCC supply
voltage. An interface based on RS232 standard levels (+/- 7 V) can be realized using level shifter ICs
such as the Maxim MAX3232.
Hardware handshake signals and synchronous operation are not supported.
A signal change on the UART RXD pin can also be used to wake up the receiver in power save mode
(see the u-blox 8 / u-blox M8 Receiver Description including Protocol Specification [2]).
☞Designs must allow access to the UART and the SAFEBOOT_N pin for future service, updates, and
reconfiguration.
2.2.2 Display data channel (DDC) interface
An I2C-compatible display data channel (DDC) interface is available for serial communication with a
host CPU.

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☞The SCL and SDA pins have internal pull-up resistors sufficient for most applications. However,
depending on the speed of the host and the load on the DDC lines additional external pull-up
resistors might be necessary. For the speed and clock frequency, see the ZOE-M8 Data sheet [1].
☞To make use of DDC interface, the D_SEL pin must be left open.
☞The ZOE-M8 GNSS SiPs DDC interface provides serial communication with u-blox cellular
modules. See the specification of the applicable cellular module to confirm compatibility.
2.2.3 SPI interface
Use the SPI interface to provide a serial communication with a host CPU. If the SPI interface is used,
UART and DDC are deactivated, because they share the same pins.
☞To make use of the SPI interface, the D_SEL pin must be connected to GND.
2.2.4 SQI interface
An external SQI (Serial Quad Interface) flash memory can be connected to the ZOE-M8 GNSS SiPs.
The SQI interface provides the following options:
Store the current configuration permanently
Save data logging results
Hold AssistNow Offline and AssistNow Autonomous data
☞In addition, the ZOE-M8 GNSS SiPs can make use of a dedicated flash firmware with an external
SQI flash memory. The flash memory with these SiPs can be used to run firmware out of flash and
to update the firmware as well. Running the firmware from the SQI flash requires a minimum SQI
flash size of 8 Mbit.
☞If the flash is not used to run the firmware, it has to be programmed with the FIS-only option.
☞The voltage level of the SQI interface follows the VCC level. Therefore, the SQI flash must be
supplied with the same voltage as VCC of the ZOE-M8 SiPs. It is recommended to place a
decoupling capacitor (C4) close to the supply pin of the SQI flash.
☞Make sure that the SQI flash supply range matches the voltage supplied at VCC.
Figure 2: Connecting an external SQI flash memory
An SQI flash size of 8 Mbit is sufficient to save AssistNow Offline and AssistNow Autonomous
information as well as current configuration data. However, for ZOE-M8 SiPs to run firmware from the
SQI flash and provide space for logging results, a minimum size of 8 Mbit may not be sufficient
depending on the amount of data to be logged.

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☞For more information about supported SQI flash devices, see section A.3.
☞Make sure that the SAFEBOOT_N pin is available for entering safe boot mode. Programming the
SQI flash memory with a flash firmware is done typically at production. For this purpose, the ZOE-
M8 GNSS SiPs must enter the safe boot mode. For more information about SAFEBOOT_N pin, see
section 2.6.
2.3 I/O pins
All I/O pins make use of internal pull-ups to VCC. Thus, there is no need to connect unused pins to
VCC.
2.3.1 Time pulse
A configurable time pulse signal is available with the ZOE-M8 GNSS SiPs.
The TIMEPULSE output generates pulse trains synchronized with GPS or UTC time grid with intervals
configurable over a wide frequency range. Thus, it may be used as a low frequency time
synchronization pulse or as a high frequency reference signal.
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 [2].
2.3.2 External interrupt
EXTINT is an external interrupt pin with fixed input voltage thresholds with respect to VCC (see the
ZOE-M8 Data sheet [1] for more information). It can be used for wake-up functions in power save
mode on all u-blox M8 SiPs and modules and for aiding, leave open if unused. By default, the external
interrupt is disabled.
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 TXD Ready feature to indicate that the receiver has data to transmit.
For further information, see the u-blox 8 / u-blox M8 Receiver Description Including Protocol
Specification [2].
☞If the EXTINT is configured for on/off switching of the ZOE-M8 GNSS SiPs, the internal pull-up
becomes disabled. Therefore ensure that the EXTINT input is always driven within the defined
voltage level by the host.
2.3.3 External LNA enable
LNA_EN pin can be used to turn on and off an external LNA. The external LNA will be turned off in
power save mode in on/off operation in OFF stage, or in software backup mode the external LNA will
also be turned off.
2.3.4 Electromagnetic interference and I/O lines
Any I/O signal line (length > ~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, lines
where 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 17).