u-blox ZOE-M8B User Manual
Abstract
This manual provides hardware and system design instructions for the u-blox ZOE-M8B GNSS SiP
module.
www.u-blox.com
UBX-17045131 - R06
ZOE-M8B
Ultra-small, super low power u-blox M8 GNSS SiP module
System integration manual
ZOE-M8B - System integration manual
Title
ZOE-M8B
Subtitle
Ultra-small, super low power u-blox M8 GNSS SiP module
Document type
System integration manual
Document number
UBX-17045131
Revision and date
R06
7-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
ROM version
PCN reference
ZOE-M8B
ZOE-M8B-0-10
ROM SPG 3.51
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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Contents
Document information ................................................................................................................................ 2
Contents .......................................................................................................................................................... 3
1 Hardware description ........................................................................................................................... 6
1.1 Overview ........................................................................................................................................................ 6
1.2 Low power operation .................................................................................................................................. 6
1.2.1 Super-E mode overview ..................................................................................................................... 6
1.2.2 Super-E mode power consumption ................................................................................................. 7
2 Design-in ................................................................................................................................................ 12
2.1 Power management .................................................................................................................................12
2.1.1 Overview .............................................................................................................................................12
2.1.2 Power modes .....................................................................................................................................12
2.2 Communication interfaces .....................................................................................................................15
2.2.1 UART interface ..................................................................................................................................15
2.2.2 Display data channel (DDC) interface ...........................................................................................16
2.2.3 SPI interface ......................................................................................................................................16
2.2.4 SQI interface ......................................................................................................................................16
2.3 I/O pins .........................................................................................................................................................17
2.3.1 External interrupt .............................................................................................................................17
2.3.2 External LNA enable .........................................................................................................................17
2.3.3 Electromagnetic interference and I/O lines .................................................................................17
2.4 Real-time clock (RTC) ...............................................................................................................................18
2.4.1 RTC using a crystal ...........................................................................................................................18
2.4.2 RTC using an external clock ...........................................................................................................18
2.4.3 Time aiding .........................................................................................................................................18
2.5 RF input .......................................................................................................................................................18
2.5.1 Passive antenna ................................................................................................................................19
2.5.2 Active antenna ..................................................................................................................................20
2.6 Safe boot mode (SAFEBOOT_N) ............................................................................................................20
2.7 System reset (RESET_N) ........................................................................................................................20
2.8 Pin description ...........................................................................................................................................21
2.9 Typical schematic .....................................................................................................................................23
2.10 Migration from ZOE-M8G to ZOE-M8B................................................................................................23
2.11 Design-in checklist ....................................................................................................................................24
2.11.1 General considerations ....................................................................................................................24
2.11.2 Schematic design-in for ZOE-M8B GNSS SiP ............................................................................24
2.12 Layout design-in checklist ......................................................................................................................24
2.13 Layout ..........................................................................................................................................................25
2.13.1 Footprint .............................................................................................................................................25
2.13.2 Paste mask ........................................................................................................................................26
2.13.3 Placement ..........................................................................................................................................26
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2.13.4 Layout design-in: Thermal management ....................................................................................26
2.14 EOS/ESD/EMI precautions ......................................................................................................................26
2.14.1 Electrostatic discharge (ESD) ........................................................................................................26
2.14.2 ESD protection measures ...............................................................................................................27
2.14.3 Electrical overstress (EOS) .............................................................................................................27
2.14.4 EOS protection measures ...............................................................................................................27
2.14.5 Electromagnetic interference (EMI) .............................................................................................27
2.14.6 Applications with cellular modules ...............................................................................................28
3 System integration ............................................................................................................................ 31
3.1 Backup and time aiding for power off ...................................................................................................31
3.2 Using multi-GNSS Assistance (MGA) ...................................................................................................32
3.2.1 AssistNow™ Online...........................................................................................................................32
3.2.2 AssistNow™ Offline (ANO) ..............................................................................................................33
3.2.3 AssistNow™ Autonomous ..............................................................................................................33
3.3 Data batching ............................................................................................................................................33
4 Product handling and soldering ..................................................................................................... 35
4.1 Packaging, shipping, storage and moisture preconditioning ..........................................................35
4.2 ESD handling precautions .......................................................................................................................35
4.3 Safety precautions ...................................................................................................................................35
4.4 Soldering .....................................................................................................................................................36
4.4.1 Soldering paste .................................................................................................................................36
4.4.2 Reflow soldering ................................................................................................................................36
4.4.3 Optical inspection .............................................................................................................................36
4.4.4 Repeated reflow soldering ..............................................................................................................36
4.4.5 Wave soldering ..................................................................................................................................36
4.4.6 Rework ................................................................................................................................................36
4.4.7 Use of ultrasonic processes ...........................................................................................................36
5 Product testing ................................................................................................................................... 37
5.1 Test parameters for OEM manufacturer .............................................................................................37
5.2 System sensitivity test ............................................................................................................................37
5.2.1 Guidelines for sensitivity tests ......................................................................................................37
5.2.2 “Go/No go” tests for integrated devices ......................................................................................37
Appendix ....................................................................................................................................................... 38
A Glossary ................................................................................................................................................. 38
B Recommended components ........................................................................................................... 39
B.1 External RTC (Y1) ......................................................................................................................................39
B.2 RF bandpass filter (F1) ............................................................................................................................39
B.3 Optional SQI flash (U3).............................................................................................................................40
B.4 External LNA (U1) .....................................................................................................................................40
B.5 RF ESD protection diode ..........................................................................................................................40
B.6 Ferrite beads (FB1) ...................................................................................................................................40
B.7 Feed-through capacitors .........................................................................................................................41
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B.8 Standard capacitors .................................................................................................................................41
Related documents ................................................................................................................................... 42
Revision history .......................................................................................................................................... 42
Contact .......................................................................................................................................................... 43
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1 Hardware description
1.1 Overview
The u-blox ZOE-M8B standard precision GNSS SiP module features the high-performance u-blox M8
GNSS engine. The ultra-miniature form factor integrates a complete GNSS receiver solution including
SAW filter, LNA and TCXO.
The ZOE-M8B GNSS SiP is targeted for applications that require a small size without compromising
the performance. It features the new Super-Efficient (Super-E) operation mode, providing a unique
balance between power consumption and performance.
For RF optimization, the ZOE-M8B SiP integrates a front-end SAW filter and an additional front-end
LNA for increased jamming immunity and easier antenna integration. The Super-E mode allows
automatic LNA duty-cycling for reduced power consumption. A passive antenna can be used to
provide a highly integrated system solution with minimal eBOM.
The ZOE-M8B optimizes the overall system power consumption by excluding the need for any heavy
signal processing on the application processor. In the Super-E mode, the system can operate with
absolute minimal current consumption during power-optimized periods. Navigation data can be
stored internally while the application processor is in deep sleep (data batching). Super-E mode, LNA
duty cycling, and intelligent power management are breakthroughs for low-power applications.
The ZOE-M8B GNSS SiP 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-M8B 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 Low power operation
The ZOE-M8B GNSS SiP is designed for use in portable and wearable applications. It is intended to
run in Super-E mode and defaults to this mode on power up. The Super-E mode provides the best
balance between current consumption vs. performance. The Super-E mode also enables automatic
duty cycling of both the internal and optional external LNA to further lower the total power
consumption.
For specific power saving applications, the host processor has an option to put the receiver into
backup state. All essential data for quick re-starting of navigation can be saved either on the receiver
side or on the host processor side.
The data batching feature allows position fixes to be stored in the RAM of the GNSS receiver for later
retrieval in one batch. Batching of position fixes happens independently of the host system, and can
continue while the host is powered down with as many as 300 sets of position, accuracy estimate,
speed, and time data.
Used in combination with multi-GNSS Assistance data, the ZOE-M8B GNSS SiP not only features fast
TTFF and good sensitivity, but also ensures minimal power consumption, since A-GNSS enables the
chip to maximize its power-optimized period.
1.2.1 Super-E mode overview
Super-E mode provides optimal power savings while maintaining good level of position and speed
accuracy. ZOE-M8B defaults to Super-E mode on power up.
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On receiver startup, the Super-E mode uses the acquisition engine until a sufficient number of
satellites is acquired for reliable GNSS performance, and uses the tracking engine to track the
satellites. By default, the acquisition engine is active at least for 5 minutes after the receiver startup
to read the ephemeris of many satellites. The tracking engine is duty-cycled adaptively according to
the signal strength in order to provide the best balance between power consumption and navigation
performance.
Super-E mode offers choice of 1 Hz (default), 2 Hz, or 4 Hz operation. In addition, a slower operation
rate with an interval of 1 – 10 s can be selected. The higher 2 Hz and 4 Hz navigation rates improve
the navigation accuracy, but they also consume more power. The power mode can be selected with
the configuration message UBX-CFG-PMS. Update periods longer than 1 s are set with the Extended
Power Management configuration message UBX-CFG-PM2.
Super-E mode has two settings to tune the receiver operation. The “performance” (default) setting
provides the best balance for power vs. performance. The “power save” setting provides up to an
additional 15-20% power savings at the cost of position accuracy. The setting can be selected with
the optTarget configuration option of the Extended Power Management configuration message UBXCFG-PM2.
During the tracking phase of the Super-E mode, the satellite reception is duty-cycled and it is turned
off most of the time. The receiver reads data from the satellite transmission only occasionally. Mostly
it just checks where the tracked satellites are at that time, and then calculates the position. With
strong enough signal strength, the active time is 1/12 of each navigation cycle. If signal level goes too
low, the active time can go up to 1/3 of each navigation cycle.
Optimal efficiency of Super-E mode is achieved with a strong signal level. To ensure best efficiency,
significant power savings, and good tracking performance, the signal strength of the strongest
satellites should be at least -146 dBm to -144 dBm (C/N0 value of 28 dBHz to 30 dBHz). Super-E mode
will still work if the signal level goes lower, but efficiency will then degrade.
Some satellites become obscured every now and then when the receiver moves. In Super-E mode, the
receiver needs to be able to track at least 6 - 8 satellites constantly. If some of the currently used
satellites are not in view, the receiver can start to use some other known satellite. If too many of the
currently known satellites are obscured, the receiver must restart the acquisition engine and stop
power-optimized tracking to read ephemeris data for the new satellites. This acquisition phase lasts
only as long as minimally needed.
Navigation performance improves if ephemeris of many more satellites is known beforehand, because
the receiver can then use new satellites even if several of the previously used satellites are out of view.
The five-minute (default) initial acquisition period on receiver startup helps to read the ephemeris of
many satellites. Ephemeris data can be provided to the receiver also with AssistNow mechanism. If
the ephemeris data for many satellites are known, then there is no need to read this data from the
satellite transmission. Such preloading of data improves performance especially when the receiver is
started in a low signal level environment (for example, indoors). The initial acquisition period can be
adjusted with the Extended Power Management configuration message UBX-CFG-PM2. The
minimum value for an initial acquisition period is 0 s, which can be used if, for example, valid AssistNow
Online data or up to one-day old AssistNow Offline data are available. Depending on the age of the
aiding data and GNSS signal conditions, an initial acquisition period up to two or three minutes may
be beneficial.
1.2.2 Super-E mode power consumption
1.2.2.1 Super-E states
ZOE-M8B defaults to the Super-E mode on powerup. The receiver starts up in the full-power
acquisition state to search for satellites. The acquisition state continues until there is a valid 3D fix
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and the receiver has enough information about available satellites. For the 3D fix, the receiver needs
to receive data for current GNSS time and information of at least four satellites (red points in Figure
1). The receiver continues searching for more satellites in the acquisition state (yellow dots in Figure
1) until it has enough information for proper low-power operation. By default, this search lasts for five
minutes after the receiver start-up, but can be adjusted if, for instance, AssistNow data is used.
After the initial acquisition state, the receiver enters the power-optimized tracking state (shown by
the green dots in Figure 1). This is the low-power state of the Super-E mode. If the set of available
satellites gets too small, the receiver again enters acquisition or tracking state for a short period until
it has enough satellites to track. This is shown by the brief peaks in current consumption during the
power-optimized tracking state in Figure 1.
The state of the receiver is given in the psmState field in the UBX-NAV-PVT message.
Figure 1: Current consumption in different states in Super-E mode.
1.2.2.2 Super-E power consumption examples
The sensitivity, accuracy, and power efficiency of a GNSS receiver depend heavily on the availability,
strength and quality of the GNSS signal. If the signal is attenuated, blocked or reflected, the power
consumption, acquisition speed, and positioning accuracy suffer. Application design, including
antenna performance, also contributes to the signal quality. Use of assistance often helps to improve
both performance and power consumption.
In the following examples, current consumption in Super-E mode is shown for open, forest and urban
environment over a 30-minute period. The results are presented for the default mode, that is, 1 Hz
Super-E “performance” setting with GPS, GLONASS and QZSS enabled. A wrist-worn sports watch
with weak and constantly changing reception was used to receive the GNSS signal.
Current consumption in an open environment is shown in Figure 2 and Figure 3 for continuous and
Super-E mode, respectively. The average tracking current in continuous mode is 45.7 mA whereas in
Super-E mode the average current drops to 13.3 mA after the (adjustable) initial acquisition period.
Use of assistance improves TTFF but also further reduces average current consumption by
approximately 15% (Figure 4).
The effect of environment on current consumption can be seen in Figure 3 (open), Figure 5 (forest)
and Figure 7 (urban). The power optimization in Super-E mode performs best in an open environment,
with the current consumption increasing with deteriorating signal conditions. Under heavy multipath
and blocking of satellites, the receiver may need to briefly exit power-optimized tracking to acquire
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new satellites. The use of assistance improves TTFF and reduces current consumption in all cases
(as seen in Figure 4, Figure 6 and Figure 8).
Figure 2: ZOE-M8B continuous mode current consumption in open environment
Figure 3: ZOE-M8B Super-E mode current consumption in open environment
Figure 4: ZOE-M8B Super-E mode current consumption in open environment with AssistNow Offline
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Figure 5: ZOE-M8B Super-E mode current consumption in obstructed environment (forest)
Figure 6: ZOE-M8B Super-E mode current consumption in obstructed environment (forest) with AssistNow Offline
Figure 7: ZOE-M8B Super-E mode current consumption in urban environment
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Figure 8: ZOE-M8B Super-E mode current consumption in urban environment with AssistNow Offline
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2 Design-in
To obtain good performance with the ZOE-M8B GNSS SiP, 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
2.1.1 Overview
The ZOE-M8B GNSS SiP provides two supply pins: VCC and V_BCKP. They can be supplied
independently or tied together, depending on the intended application.
2.1.1.1 Main supply voltage (VCC)
During operation, the ZOE-M8B GNSS SiP receives power through the VCC pin. Built-in LDOs generate
stabilized voltages for the core and RF domains of the chip. 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-M8B GNSS SiP are supplied by the VCC voltage.
2.1.1.2 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 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 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-M8B Data sheet
[1].
2.1.2 Power modes
The ZOE-M8B GNSS SiP can operate in two power modes:
Super-E Mode to optimize power consumption (default mode)
Continuous mode for best GNSS reception
The available power modes are illustrated in Figure 9. The Super-E Mode has three predefined
settings for 1 Hz (default), 2 Hz and 4 Hz update rates. In addition, Super-E mode supports longer
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user-defined update periods from 1 s up to 10 s. The continuous mode has two predefined settings,
full power and balanced.
For specific power saving applications, the host system has an option to put the receiver into backup
state. All essential data for quick re-starting of navigation can be saved either on the receiver or on
the host processor side.
☞ Unlike some other u-blox M8 receivers, the ZOE-M8B GNSS SiP does not support self-managed
ON/OFF power saving mode, in which the receiver periodically puts itself into backup state when
an operation interval longer than 10 s is selected.
Figure 9: ZOE-M8B power modes
Figure 10: ZOE-M8B Super-E mode configuration options
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