Ublox MAX-7 Series Quick setup guide

MAX-7 / NEO-7 / LEA-7
u-blox 7 GPS/GNSS modules
Hardware Integration Manual
Abstract
This document describes the features and specifications of the cost
effective and high-performance MAX-7, NEO-7 and LEA-
7
GPS/GLONASS/QZSS modules featuring the u-
blox 7 positioning
engine.
These compact, easy to integrate stand-
alone GPS/GNSS receiver
modules combine exceptional GPS/GNSS performance with highly
flexible power, design, and connectivity options. Their compact
form factors and 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.
locate, communicate, accelerate
www.u-blox.com

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Document Information
Title MAX-7 / NEO-7 / LEA-7
Subtitle u-blox 7 GPS/GNSS modules
Document type Hardware Integration Manual
Document number GPS.G7-HW-11006-1
Document status Objective Specification
Document status information
Objective
Specification
This document contains target values. Revised and supplementary data will be published
later.
Advance
Information
This document contains data based on early testing. Revised and supplementary data will
be published later.
Preliminary This document contains data from product verification. Revised and supplementary data
may be published later.
Released This document contains the final product specification.
This document applies to the following products:
Name Type number ROM/FLASH version PCN reference
MAX-7C-0 All ROM1.00
MAX-7Q-0 All ROM1.00
MAX-7W-0 All ROM1.00
NEO-7N-0 All FLASH1.00
NEO-7M-0 All ROM1.00
LEA-7N-0 All FLASH1.00
This document and the use of any information contained therein, is subject to the acceptance of the u-blox
terms and conditions. They can be downloaded from www.u-blox.com.
u-blox makes no warranties based on the accuracy or completeness of the contents of this document and
reserves the right to make changes to specifications and product descriptions at any time without notice.
u-blox reserves all rights to this document and the information contained herein. Reproduction, use or
disclosure to third parties without express permission is strictly prohibited. Copyright © 2012, u-blox AG.
u-blox®is a registered trademark of u-blox Holding AG in the EU and other countries. ARM®is the registered
trademark of ARM Limited in the EU and other countries.

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Preface
u-blox Technical Documentation
As part of our commitment to customer support, u-blox maintains an extensive volume of technical
documentation for our products. In addition to our product-specific technical data sheets, the following manuals
are available to assist u-blox customers in product design and development.
•GPS Compendium: This document, also known as the GPS book, provides a wealth of information
regarding generic questions about GPS system functionalities and technology.
•Receiver Description including Protocol Specification: Messages, configuration and functionalities of
the u-blox 7 software releases and positioning modules are explained in this document.
•Hardware Integration Manual: This Manual provides hardware design instructions and information on
how to set up production and final product tests.
•Application Note: document provides general design instructions and information that applies to all u-blox
GPS/GNSS positioning modules. See section Related documents for a list of Application Notes related to your
GPS/GNSS receiver.
How to use this Manual
The MAX-7, NEO-7 and LEA-7 Hardware Integration Manual provides the necessary information to successfully
design in and configure these u-blox 7-based positioning modules. For navigating this document, please note
the following:
This manual has a modular structure. It is not necessary to read it from the beginning to the end. To help in
finding needed information, a brief section overview is provided below
1. Hardware description: This chapter introduces the basics of function and architecture of the u-blox 7
modules.
2. Design: This chapter provides the information necessary for a successful design.
3. Product handling: This chapter defines packaging, handling, shipment, storage and soldering.
4. Product testing: This chapter provides information about testing of OEM positioning modules in
production.
5. Migration to u-blox-7 modules: includes guidelines on how to successfully migrate to u-blox 7 designs.
The following symbols are used to highlight important information within the manual:
An index finger points out key information pertaining to module integration and performance.
A warning symbol indicates actions that could negatively influence or damage the module.
Questions
If you have any questions about u-blox 7 Hardware Integration, please:
•Read this manual carefully.
•Contact our information service on the homepage http://www.u-blox.com
•Read the questions and answers on our FAQ database on the homepage http://www.u-blox.com

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Technical Support
Worldwide Web
Our website (www.u-blox.com) is a rich pool of information. Product information, technical documents and
helpful FAQ can be accessed 24h a day.
By E-mail
If you have technical problems or cannot find the required information in the provided documents, contact the
nearest of the Technical Support offices by email. Use our service pool email addresses rather than any personal
email address of our staff. This ensures that we process your request as soon as possible. You will find the
contact details at the end of the document.
Helpful Information when Contacting Technical Support
When contacting Technical Support please have the following information ready:
•Receiver type (e.g. NEO-7N-0-000), Datacode (e.g. 172100.0100.000) and firmware version (e.g. ROM1.0)
•Receiver configuration
•Clear description of your question or the problem together with a u-center logfile
•A short description of the application
•Your complete contact details

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Contents
Preface ................................................................................................................................3
Contents..............................................................................................................................5
1Quick reference ............................................................................................................8
2Hardware description ..................................................................................................8
2.1 Overview .................................................................................................................................................................................8
2.2 Architecture.............................................................................................................................................................................8
2.3 Operating modes .....................................................................................................................................................................9
2.3.1 Continuous Mode................................................................................................................................................................9
2.3.2 Power Save Mode................................................................................................................................................................9
2.4 Configuration ..........................................................................................................................................................................9
2.5 Connecting power ...................................................................................................................................................................9
2.5.1 VCC: Main Supply Voltage ...................................................................................................................................................9
2.5.2 VCC_IO: IO Supply Voltage (MAX-7)...................................................................................................................................10
2.5.3 V_BCKP: Backup Supply Voltage ........................................................................................................................................10
2.5.4 VDD_USB: USB interface power supply (NEO-7/LEA-7).........................................................................................................10
2.5.5 VCC_RF: Output Voltage RF section....................................................................................................................................10
2.5.6 V_ANT: Antenna supply (NEO-7/LEA-7)...............................................................................................................................11
2.6 Interfaces...............................................................................................................................................................................11
2.6.1 UART ................................................................................................................................................................................11
2.6.2 USB...................................................................................................................................................................................11
2.6.3 Display Data Channel (DDC)...............................................................................................................................................13
2.6.4 SPI (NEO-7)........................................................................................................................................................................13
2.7 I/O pins..................................................................................................................................................................................13
2.7.1 RESET_N: Reset input.........................................................................................................................................................13
2.7.2 EXTINT: External interrupt ..................................................................................................................................................13
2.7.3 D_SEL: Interface select (NEO-7)...........................................................................................................................................14
2.7.4 TX-ready signal ..................................................................................................................................................................14
2.7.5 ANT_ON: Antenna ON (LNA enable) (NEO-7N, MAX-7Q, MAX-7C)......................................................................................14
2.7.6 Antenna Short circuit detection (LEA-7N, MAX-7W) ............................................................................................................14
2.7.7 Antenna open circuit detection ..........................................................................................................................................14
2.7.8 TIMEPULSE ........................................................................................................................................................................14
3Design .........................................................................................................................15
3.1 Design checklist .....................................................................................................................................................................15
3.1.1 Schematic checklist............................................................................................................................................................15
3.1.2 Layout checklist .................................................................................................................................................................16
3.1.3 Antenna checklist ..............................................................................................................................................................16
3.2 Design considerations for minimal designs ..............................................................................................................................16
3.2.1 Minimal design (NEO-7N)...................................................................................................................................................17
3.2.2 Minimal design (MAX-7Q)..................................................................................................................................................19
3.2.3 Minimal design (LEA-7N)....................................................................................................................................................20
3.3 Layout ...................................................................................................................................................................................21
3.3.1 Footprint and paste mask...................................................................................................................................................21
3.3.2 Placement .........................................................................................................................................................................22
3.3.3 Antenna connection and ground plane design ....................................................................................................................23

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3.3.4 General design recommendations: .....................................................................................................................................24
3.3.5 Antenna micro strip ...........................................................................................................................................................25
3.4 Antenna and Antenna supervision ..........................................................................................................................................26
3.4.1 Antenna design with passive antenna.................................................................................................................................26
3.4.2 Active antenna design not using antenna supervisor (NEO-7N, NEO-7M, MAX-7C, MAX-7Q) ...............................................27
3.4.3 Antenna design with active antenna using antenna supervisor (LEA-7N, MAX-7W) ..............................................................28
3.4.4 Design with GLONASS / GPS active antenna .......................................................................................................................33
3.4.5 Design with GLONASS / GPS passive antenna .....................................................................................................................34
3.5 Recommended parts ..............................................................................................................................................................35
3.5.1 Recommended GPS & GLONASS active antenna (A1) ..........................................................................................................36
3.5.2 Recommended GPS & GLONASS passive patch antenna ......................................................................................................36
3.5.3 Recommended GPS & GLONASS passive chip antenna ........................................................................................................36
4Migration to u-blox-7 modules .................................................................................37
4.1 Migrating u-blox 6 designs to a u-blox 7 module.....................................................................................................................37
4.2 Hardware migration ...............................................................................................................................................................38
4.2.1 Hardware compatibility: .....................................................................................................................................................38
4.2.2 Hardware migration NEO-6 -> NEO-7 .................................................................................................................................39
4.2.3 Hardware migration MAX-6 -> MAX-7 ...............................................................................................................................40
4.2.4 Hardware migration LEA-6N -> LEA-7N ..............................................................................................................................41
4.3 Software migration ................................................................................................................................................................42
4.3.1 Software compatibility .......................................................................................................................................................42
4.3.2 Messages no longer supported...........................................................................................................................................42
5Product handling........................................................................................................43
5.1 Packaging, shipping, storage and moisture preconditioning .....................................................................................................43
5.2 Soldering ...............................................................................................................................................................................43
5.2.1 Soldering paste..................................................................................................................................................................43
5.2.2 Reflow soldering................................................................................................................................................................43
5.2.3 Optical inspection ..............................................................................................................................................................44
5.2.4 Cleaning ...........................................................................................................................................................................44
5.2.5 Repeated reflow soldering..................................................................................................................................................44
5.2.6 Wave soldering..................................................................................................................................................................45
5.2.7 Hand soldering ..................................................................................................................................................................45
5.2.8 Rework .............................................................................................................................................................................45
5.2.9 Conformal coating.............................................................................................................................................................45
5.2.10 Casting .........................................................................................................................................................................45
5.2.11 Grounding metal covers ................................................................................................................................................45
5.2.12 Use of ultrasonic processes ............................................................................................................................................46
5.3 EOS/ESD/EMI precautions .......................................................................................................................................................46
5.3.1 Electrostatic discharge (ESD)...............................................................................................................................................46
5.3.2 ESD handling precautions...................................................................................................................................................46
5.3.3 ESD protection measures ...................................................................................................................................................47
5.3.4 Electrical Overstress (EOS)...................................................................................................................................................47
5.3.5 EOS protection measures ...................................................................................................................................................47
5.3.6 Electromagnetic interference (EMI) .....................................................................................................................................48
5.3.7 Applications with wireless modules LEON / LISA..................................................................................................................49
6Product testing ...........................................................................................................51
6.1 u-blox in-series production test ...............................................................................................................................................51
6.2 Test parameters for OEM manufacturer ..................................................................................................................................51
6.3 System sensitivity test .............................................................................................................................................................52

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6.3.1Guidelines for sensitivity tests.............................................................................................................................................52
6.3.2 ‘Go/No go’ tests for integrated devices ...............................................................................................................................52
Appendix ..........................................................................................................................53
AAbbreviations .............................................................................................................53
Related documents...........................................................................................................53
Revision history................................................................................................................54
Contact..............................................................................................................................55

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1Quick reference
When using this manual for a design, make sure you also have the Data Sheet for the specific positioning
module (see the Related documents section).
For information about new designs, see section 3.1.
For information about migration, see sections 4.2.3 (MAX-7), 4.2.2 (NEO-7) and 4.2.4 (LEA-7).
Layout Power Interfaces I/Os Antenna
See section 3.3 See sections 2.3
and 2.4 See section 2.6 See section 2.7 See sections 2.5.6, 3.4, 3.5
Table 1: Quick guide to this document
2Hardware description
2.1 Overview
u-blox 7 modules are standalone GPS/GNSS positioning modules featuring the high performance u-blox 7
positioning engine. Available in industry standard form factors in leadless chip carrier (LCC) packages, 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 module Data Sheet.
To determine which u-blox product best meets your needs, see the product selector tables on the u-blox
website (www.u-blox.com).
2.2 Architecture
u-blox 7 modules consist of two functional parts - the RF block and the digital block (see Figure 1).
The RF block includes the input matching elements, the SAW band pass filter, the integrated LNA and the
oscillator, while the digital block contains the u-blox 7 GPS/GNSS engine, the RTC crystal and additional
elements such as the optional FLASH Memory for enhanced programmability and flexibility.
Figure 1: u-blox-7 block diagram

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2.3 Operating modes
u-blox receivers support different power modes. These modes represent strategies of how to control the
acquisition and tracking engines in order to achieve either the best possible performance or good performance
with reduced power consumption.
2.3.1 Continuous Mode
During a cold start, a receiver in Continuous Mode continuously deploys the acquisition engine to search for all
satellites. Once the receiver can calculate a position and track a sufficient number of satellites, the acquisition
engine powers off, resulting in significant power savings. The tracking engine continuously tracks acquired
satellites and acquires other available or emerging satellites. Whenever the receiver can no longer calculate a
position or the number of satellites tracked is below the sufficient number, the acquisition engine powers on
again to guarantee a quick reacquisition. Even if the acquisition engine powers off, the tracking engine
continues to acquire satellites.
For best performance, use continuous mode.
2.3.2 Power Save Mode
Two Power Save Mode (PSM) operations called ON/OFF and Cyclic tracking are available. These use different
ways to reduce the average current consumption in order to match the needs of the specific application. PSM
operations are set and configured using serial commands. For more information, see the u-blox 7 Receiver
Description Including Protocol Specification [4].
The system can shut down an optional external LNA using the ANT_ON signal in order to optimize power
consumption, see section 2.7.5.
Using the USB Interface is not recommended with Power Save Mode since the USB standard does not
allow a device to be non-responsive. Thus, it is not possible to have full advantage of Power Save Mode
operations in terms of saving current consumption.
Power Save Mode is not supported in GLONASS mode.
2.4 Configuration
The configuration settings can be modified using UBX protocol configuration messages. 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.
Configuration can be saved permanently in SQI flash.
2.5 Connecting power
u-blox 7 positioning modules have up to five power supply pins: VCC, VCC_IO, V_BCKP, V_ANT and
VDD_USB.
2.5.1 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 (see datasheet for specification) for a short time.
Some u-blox 7 modules integrate a DC/DC converter. This allows reduced power consumption, especially when
using a main supply voltage above 2.5 V.
When switching from backup mode to normal operation or at start-up, u-blox 7 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.

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Use a proper GND concept. Do not use any resistors or coils in the power line. For ground plane design
see section 3.3.3
2.5.2 VCC_IO: IO Supply Voltage (MAX-7)
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.
2.5.3 V_BCKP: Backup Supply Voltage
In case of a power failure on the module supply, the real-time clock (RTC) and battery backed RAM (BBR) are
supplied by V_BCKP. Use of valid time and the GPS/GNSS orbit data at start up will improve the GPS/GNSS
performance i.e. enables Hotstarts, Warmstarts, AssistNow Autonomous and AssistNow Offline. If no backup
battery is connected, the module performs a Coldstart 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 (or to VCC if not avaiable).
As long as the u-blox 7 module is supplied to VCC and VCC_IO, the backup battery is disconnected
from the RTC and the BBR to avoid unnecessary battery drain (see Figure 2). In this case, VCC supplies
power to the RTC and BBR.
Figure 2: Backup battery and voltage (for exact pin orientation, see data sheet)
2.5.3.1 RTC derived from the system clock; “Single Crystal” feature (MAX-7C)
On MAX-7C, the reference frequency for the RTC clock can be internally derived from the crystal system clock
frequency (26 MHz) when in Hardware Backup Mode. This feature is called “single crystal” operation. The crystal
will be supplied by the backup battery at V_BCKP in the event of a power failure at VDD_IO to derive and
maintain the RTC clock. This makes MAX-7C a more cost efficient solution at the expense of a higher backup
current compared to the usage of an ordinary RTC crystal on other MAX-7 variants. The capacity of the backup
battery at V_BCKP must therefore be increased accordingly if Hardware Backup Mode is needed.
2.5.4 VDD_USB: USB interface power supply (NEO-7/LEA-7)
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 2.6.2.1.
2.5.5 VCC_RF: Output Voltage RF section
The VCC_RF pin can supply an active antenna or external LNA. For more information, see section 3.4.3.2.

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2.5.6 V_ANT: Antenna supply (NEO-7/LEA-7)
The V_ANT pin is available to provide antenna bias voltage to supply an optional external active antenna. For
more information, see section 3.4.3.2.
If not used, connect the V_ANT pin to GND.
2.6 Interfaces
2.6.1 UART
u-blox 7 positioning modules include a Universal Asynchronous Receiver Transmitter (UART) serial interface
RxD/TxD supporting configurable baud rates. The baud rates supported are specified in the u-blox 7 Receiver
Description Including Protocol Specification [4]
The signal output and input levels are 0 V to VCC for NEO-7 and LEA-7 modules, and 0 V to VCC_IO for MAX-7
modules. 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.
2.6.2 USB
A USB version 2.0 FS (Full Speed, 12 Mb/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 XP, Windows Vista, and Windows 7 operating
systems (also Windows 8 compatible). These drivers are available at our website at www.u-blox.com
2.6.2.1 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 3 and listed in Table 2. To comply with
USB specifications, VBUS must be connected through an LDO (U1) to pin VDD_USB on the module.
If the USB device is self-powered, 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 i.e. VBUS is not supplied.
If the device is bus-powered, LDO (U1) does not need an enable control.
Figure 3: USB Interface

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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 GPS/GNSS receiver is operated as
a USB self-powered device, but if bus-powered LDO (U1) must be able to
deliver the maximum current. For the peak supply current, see a low-cost
DC/DC converter such as LTC3410 from Linear Technology.
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 1 kΩis recommended for USB self-powered setup. For bus-powered setup,
R11 can be ignored.
Table 2: Summary of USB external components

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2.6.3 Display Data Channel (DDC)
An I2C compatible Display Data Channel (DDC) interface is available with u-blox 7 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.
For more information about the DDC implementation, see the u-blox 7 Receiver Description Including Protocol
Specification [4].For bandwidth information see the Data Sheet. For timing, parameters consult the I2C standard
[9].
The u-blox 7 DDC interface supports serial communication with u-blox wireless modules. See the
specification of the applicable wireless module to confirm compatibility.
With u-blox 7, when reading the DDC internal register at address 0xFF (messages transmit buffer), the
master must not set the reading address before every byte is accessed, as this could cause a faulty
behavior. After every byte is read from register 0xFF the internal address counter is incremented by one,
saturating at 0xFF. Therefore, subsequent reads can be performed continuously.
2.6.4 SPI (NEO-7)
With NEO-7 modules, 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 (NEO-7) (see section 2.7.3).
For speed and clock frequency see the Data Sheet.
Figure 4 shows how to connect a u-blox GPS/GNSS receiver to a host/master. The signal on the pins must meet
the conditions specified in the Data Sheet.
Figure 4: Connecting to SPI Master
VCC_IO must have the same voltage level as the host.
2.7 I/O pins
2.7.1 RESET_N: Reset input
Driving RESET_N low activates a hardware reset of the system. Use this pin only to reset the module. Do not use
RESET_N to turn the module on and off, since the reset state increases power consumption. With u-blox 7
RESET_N is an input only.
2.7.2 EXTINT: External interrupt
EXTINT is an external interrupt pin with fixed input voltage thresholds with respect to VCC or VCC_IO (see the
data sheet for more information). It can be used for wake-up functions in Power Save Mode on all u-blox 7
modules and for aiding. Leave open if unused.

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2.7.3 D_SEL: Interface select (NEO-7)
The D_SEL Pin available on all NEO-7 Modules selects the available interfaces. SPI cannot be used simultaneously
with UART/DDC.
If open, UART and DDC are available. If pulled low, these pins are SPI Interface.
Pin NEO-7 Pin 2 D_SEL open NEO-7 Pin 2 D_SEL low
18 DDC Data SPI CS_N
19 DDC Clock SPI SCK
20 TxD SPI MISO
21 RxD SPI MOSI
Table 3: pin 2 D_SEL on NEO-7
2.7.4 TX-ready signal
The TX-ready signal indicates that 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 signal can be mapped to
UART TXD (PIO 06). The TX-ready function is disabled by default.
u-blox wireless modules (LEON FW 07.70 and LISA-U2 01S onwards) configure and enable the TX-ready
functionality automatically. This is not supported by LEON FW7.60.02 and previous versions.
For more information on configuration and remap of this pin, see the u-blox 7 Receiver Description including
Protocol Specification [4] and GPS Implementation and Aiding Features in u-blox wireless modules[10].
2.7.5 ANT_ON: Antenna ON (LNA enable) (NEO-7N, MAX-7Q, MAX-7C)
In Power Save Mode, the system can turn on/off an optional external LNA using the ANT_ON signal in order to
optimize power consumption.
2.7.6 Antenna Short circuit detection (LEA-7N, MAX-7W)
LEA-7N and MAX-7W modules include internal short circuit antenna detection. For more information, see
section 3.4.3.2.
2.7.7 Antenna open circuit detection
2.7.7.1 Antenna open circuit detection (LEA-7N)
LEA-7N modules provide antenna open circuit detection (OCD) functionality over the AADET_N pin.
AADET_N is an input pin used to report whether an external circuit has detected an external antenna or not.
Low means an antenna has been detected, while high means no external antenna has been detected. This
functionality is by default disabled.
2.7.7.2 Antenna open circuit detection (MAX-7)
Antenna open circuit detection (OCD) is not activated by default on the MAX-7 module. OCD can be mapped to
PIO13 (EXTINT). For more information about how to implement OCD, see section 3.4.3.3. To learn how to
configure OCD see the u-blox 7 Receiver Description including Protocol Specification [4].
2.7.8 TIMEPULSE
A configurable time pulse signal is available with all u-blox 7 modules. By default, the time pulse signal is
configured to 1 pulse per second. For more information see the u-blox 7 Receiver Description including Protocol
Specification [4].

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3Design
3.1 Design checklist
Designing-in a u-blox 7 module is easy, especially when based on a u-blox reference design. Nonetheless, it pays
to do a quick sanity check of the design. This section lists the most important items for a simple design check.
The design checklist can also help to avoid an unnecessary PCB respin and achieve the best possible
performance. Follow the design checklists when developing any u-blox 7 GPS/GNSS applications. This can
significantly reduce development time and costs.
3.1.1 Schematic checklist
If required, does your schematic allow for using different module variants? See the u-blox website
(www.u-blox.com) to compare the available features of u-blox 7 GPS/GNSS modules.
Plan the use of a second interface (Test points on UART, DDC or USB) for firmware updates or as a
service connector.
Power supply requirements
GPS/GNSS positioning modules require a stable power supply. In selecting a strategy to achieve a clean
and stable power supply, any resistance in the VCC supply line can negatively influence performance.
Consider the following points:
oWide power lines or even power planes are preferred.
oAvoid resistive components in the power line (e.g. narrow power lines, coils, resistors, etc.).
oPlacing a filter or other source of resistance at VCC can create significantly longer acquisition
times.
oFor ground plane design, see section 3.4.3.
Are all power supplies (VCC, VDD_USB) within the specified range? (See data sheet MAX-7:[2] NEO-7:[1]
LEA-7:[3])
Compare the peak supply current consumption of your u-blox 7 module with the specification of the
power supply. (See the data sheet for more information.)
At the module input, use low ESR capacitors that can deliver the required current/charge for switching
from backup mode to normal operation.
Backup battery
Use of valid time and the GPS/GNSS orbit data at startup will improve the GPS/GNSS performance i.e.
enables Hotstarts, Warmstarts and the AssistNow Autonomous process as well as AssistNow Offline. To
make use of these features connect a battery to V_BCKP to continue supplying the backup domain in
case of power failure at VCC_IO.
If no backup supply voltage is available, connect the V_BCKP pin to VCC_IO (or to VCC if not avaiable).

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3.1.2 Layout checklist
See section 3.3.
Is the GPS/GNSS module located according to the recommendation?
Has the grounding concept been followed?
Has the micro strip been kept as short as possible?
Add a ground plane underneath the GPS/GNSS module to reduce interference.
For improved shielding, add as many vias as possible around the micro strip, around the serial
communication lines, underneath the GPS/GNSS module etc.
Have appropriate EOS/ESD/EMI protection measures been included? This is especially important for
designs including wireless modules.
3.1.3 Antenna checklist
The total noise figure should be well below 3 dB.
If a patch antenna is the preferred antenna, choose a patch of at least 15x15x4 mm for standalone
GPS/QZSS, or choose a patch of at least 25x25x4 mm for GPS + GLONASS. For smaller antennas, an LNA
with a noise figure <2 dB is recommended. (MAX-7Q, NEO-7N)
Make sure the antenna is not placed close to noisy parts of the circuitry. (E.g. micro-controller, display,
etc.)
To optimize performance in environments with out-of band jamming sources, use an additional SAW
filter.
The micro strip must be 50 Ωand be routed in a section of the PCB where minimal interference from
noise sources can be expected.
In case of a multi-layer PCB, use the thickness of the dielectric between the signal and the first GND layer
(typically the 2nd layer) for the micro strip calculation.
If the distance between the micro strip and the adjacent GND area (on the same layer) does not exceed 5
times the track width of the micro strip, use the “Coplanar Waveguide” model in AppCad to calculate
the micro strip and not the “micro strip” model see section 3.3.5
Use an external LNA if your design does not include an active antenna when optimal performance is
important.
For information on ESD protection for patch antennas and removable antennas, see section 5.3.3 and if
you use GPS for design in combination with GSM or other radio then check sections 5.3.5 to 5.3.7.
For more information dealing with interference, issues see the GPS Antenna Application Note [5].
3.2 Design considerations for minimal designs
For a minimal design with a u-blox 7 GPS/GNSS module, the following functions and pins need consideration:
•Connect the Power supply to VCC.
•Connect VCC_IO to VCC or to the corresponding voltage.
•Assure an optimal ground connection to all ground pins of the module.
•Connect the antenna to RF_IN over a 50 Ωline and define the antenna supply (V_ANT) for active antennas
(internal or external power supply).
•Choose the required serial communication interface (UART, USB, SPI or DDC) and connect the appropriate
pins to your application.
•If you need improved start-up or use AssistNow Autonomous in your application, connect a backup supply
voltage to V_BCKP.

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3.2.1 Minimal design (NEO-7N)
This is a minimal setup for a GPS/GNSS receiver with a NEO-7N module:
Figure 5: NEO-7 passive antenna design
For active antenna design, see section 3.4.2

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Function PIN No I/O Description Remarks
Power VCC 23 I Supply Voltage Provide clean and stable supply.
GND 10,12,13,
24
I Ground Assure a good GND connection to all GND pins of the module,
preferably with a large ground plane.
V_BCKP 22 I 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 I 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 GPS signal
input from
antenna
The connection to the antenna has to 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 20 O Serial Port/ SPI
MISO
Communication interface,
Can be programmed as TX-ready for DDC interface.
If pin 2 low => SPI MISO.
RxD 21 I Serial Port / 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.
Implementations see section 2.6.2.
USB_DP 6 I/O USB I/O line
System TIMEPULSE 3 O Timepulse
Signal
Configurable Timepulse signal (one pulse per second by default).
Leave open if not used.
EXTINT 4 I External
Interrupt
External Interrupt Pin.
Internal pull-up resistor to VCC. Leave open if not used.
SDA 18 I/O DDC Data / SPI
CS_N
DDC Data
If pin 2 low => SPI chip select.
SCL
19
I
DDC Clock / SPI
SCK
DDC Clock.
If pin 2 low => SPI clock.
ANT_ON
(NEO-7N)
RESERVED
(NEO-7M)
14 O ANT_ON ANT_ON (antenna on) can be used to turn on and off an optional
external LNA.
- Reserved 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 1, 15, 16,
17
- Reserved Leave open.
Table 4: Pinout NEO-7

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3.2.2 Minimal design (MAX-7Q)
This is a minimal setup for a GPS/GNSS receiver with a MAX-7Q module:
Figure 6: MAX-7 passive antenna design
For active antenna design, see section 3.4.2
For information on increasing immunity to jammers such as GSM, see section 5.3.7.
Function PIN No I/O Description Remarks
Power VCC 8 I Supply Voltage Provide clean and stable supply.
GND 1,10,12 I Ground Assure a good GND connection to all GND pins of the module,
preferably with a large ground plane.
V_BCKP 6 I Backup Supply
Voltage
Backup supply voltage input pin. Connect to VCC_IO if not used.
Antenna RF_IN 11 I GPS signal
input from
antenna
The connection to the antenna has to be routed on the PCB. Use a
controlled impedance of 50 Ωto connect RF_IN to the antenna or
the antenna connector. DC block inside.
VCC_RF 14 O Output Voltage
RF section
Can be used for active antenna or external LNA supply.
ANT_ON
(MAX-7C/Q)
Reserved
(MAX-7W)
13 O ANT_ON
Active antenna or ext. LNA control pin in power save mode.
ANT_ON pin voltage level is VCC_IO
- Reserved Leave open
UART TXD 2 O Serial Port UART, leave open if not used, Voltage level referred VCC_IO. Can
be configured as TX-ready indication for the DDC interface.
RXD 3 I Serial Port
UART, leave open if not used, Voltage level referred VCC_IO
System TIMEPULSE 4 O Timepulse
Signal
Leave open if not used, Voltage level referred VCC_IO
EXTINT 5 I External
Interrupt
Leave open if not used, Voltage level referred VCC_IO
SDA 16 I/O DDC Pins DDC Data. Leave open, if not used.
SCL
17
I
DDC Pins
DDC Clock. Leave open, if not used.
VCC_IO 7 I
VCCC_IO
IO supply voltage. Input must be always supplied. Usually connect to
VCC Pin 8
RESET_N 9 I Reset Reset
V_ANT
(MAX-7W )
Reserved
(MAX-7C/Q)
15 I Antenna Bias
Voltage
Connect to GND (or leave open) if passive antenna is used. If an
active antenna is used, add a 10 Ωresistor in front of V_ANT input
to the Antenna Bias Voltage or VCC_RF
- Reserved Leave open
Reserved 18 - Reserved Leave open
Table 5: Pinout MAX-7

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3.2.3 Minimal design (LEA-7N)
This is a minimal setup for a GPS/GNSS receiver with a LEA-7N module:
Figure 7: LEA-7N passive antenna design
For active antenna design, see section 3.4.2
Function PIN No I/O Description Remarks
Power VCC 6 I Supply Voltage Provide clean and stable supply.
GND 7, 13, 14,
15, 17
I Ground Assure a good GND connection to all GND pins of the module
VCC_OUT 8 O Leave open if not used.
V_BCKP 11 I 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 24 I USB Power
Supply
To use the USB interface connect this pin to 3.0 – 3.6V.
If no USB serial port used connect to GND.
Antenna RF_IN 16 I GPS/GALILEO
signal input
from antenna
Use a controlled impedance transmission line of 50 Ωto connect to
RF_IN.
Do not supply DC through this pin. Use V_ANT pin to supply
power.
VCC_RF 18 O Output Voltage
RF section
Can be used to power an external active antenna (VCC_RF
connected to V_ANT with 10
Ω
). The max power consumption of
the antenna must not exceed the datasheet specification of the
module.
Leave open if not used.
V_ANT 19 I Antenna Bias
voltage
Connect to GND (or leave open) if passive antenna is used. If an
active antenna is used, add a 10 Ωresistor in front of V_ANT input
to the Antenna Bias Voltage or VCC_RF
AADET_N 20 I Active Antenna
Detect
Input pin for optional antenna supervisor circuitry. Leave open if not
used.