LEA M8S / M8T Hardware Integration Manual (UBX 13003140)

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Contents
1 Hardware description
2 Design
3 Migration to u-blox M8 modules
4 Product handling
Appendix
- Recommended parts
- A.1 Design-in recommendations in combination with cellular operation
Related documents
Revision history
Contact

LEA-M8S / LEA-M8T

u-blox M8 concurrent GNSS modules

Hardware Integration Manual

Abstract

This document describes the features and specifications of the

cost

effective and high-performance LEA-M8S and LEA-M8T modules,

which feature the u-blox M8 concurrent GNSS engine

with

reception of GPS, GLONASS, BeiDou and QZSS signals.

www.u

-blox.com

UBX

-13003140 - R08

LEA-M8S / LEA-M8T - Hardware Integration Manual

UBX-13003140 - R08 Production Information Page 2 of 31

Document Information

Title LEA-M8S / LEA-M8T

Subtitle u-blox M8 concurrent GNSS modules

Document type Hardware Integration Manual

Document number UBX-13003140

Revision and Date R08 21-Oct-2015

Document status Production Information

Document status explanation

Objective Specification Document contains target values. Revised and supplementary data will be published later.

Advance Information Document contains data based on early testing. Revised and supplementary data will be published later.

Early Production Information Document contains data from product verification. Revised and supplementary data may be published later.

Production Information Document contains the final product specification.

This document applies to the following products:

Product name Type number ROM/FLASH version PCN reference

LEA-M8S LEA-M8S-0-01 ROM 2.01 UBX-15015253

LEA-M8T LEA-M8T-0-01 ROM 2.01 / FLASH FW 2.30 TIMRAW 1.02 UBX-15012993

u-blox reserves all rights to this document and the information contained herein. Products, names, logos and designs described herein

may in whole or in part be subject to intellectual property rights. Reproduction, use, modification or disclosure to third parties of this

document or any part thereof without the express permission of u-blox is strictly prohibited.

The information contained herein is provided “as is” and u-blox assumes no liability for the use of the information. No warranty, either

express or implied, is given, including but not limited, 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. For most recent documents, visit www.u-blox.com.

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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Contents

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

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

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

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

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

1.3.1 VCC: Main Supply Voltage ................................................................................................................................................... 4

1.3.2 V_BCKP: Backup Supply Voltage .......................................................................................................................................... 4

1.3.3 VDD_USB: USB interface power supply ................................................................................................................................. 5

1.3.4 VCC_RF: Output Voltage RF section...................................................................................................................................... 5

1.3.5 V_ANT: Antenna supply ....................................................................................................................................................... 5

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

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

1.4.2 USB ..................................................................................................................................................................................... 5

1.4.3 Display Data Channel (DDC) ................................................................................................................................................. 6

1.4.4 SPI (LEA-M8T ONLY) ............................................................................................................................................................ 6

1.4.5 TX Ready signal ................................................................................................................................................................... 6

1.5 I/O pins .................................................................................................................................................................................... 7

Electromagnetic interference on I/O lines ........................................................................................................................................... 8

2 Design ........................................................................................................................... 9

2.1 Pin description ......................................................................................................................................................................... 9

2.2 Minimal design ...................................................................................................................................................................... 10

2.3 Footprint and paste mask ....................................................................................................................................................... 10

2.4 Antenna and Antenna supervision .......................................................................................................................................... 11

2.4.1 Antenna design with passive antenna ................................................................................................................................. 11

2.4.2 Active antenna design ........................................................................................................................................................ 12

3 Migration to u-blox M8 modules .............................................................................. 18

3.1 Migrating u-blox 6 designs to a u-blox M8 module .................................................................................................................. 18

3.2 Hardware migration LEA-6N -> LEA-M8S ................................................................................................................................ 18

3.3 Hardware migration LEA-6T -> LEA-M8T ................................................................................................................................. 19

3.4 Software migration ................................................................................................................................................................ 19

4 Product handling ........................................................................................................ 20

4.1 Packaging, shipping, storage and moisture preconditioning ..................................................................................................... 20

4.2 Soldering ............................................................................................................................................................................... 20

4.3 EOS/ESD/EMI precautions ....................................................................................................................................................... 23

4.4 Applications with cellular modules .......................................................................................................................................... 26

Appendix .......................................................................................................................... 28

Recommended parts ............................................................................................................................................................................ 28

A.1 Design-in recommendations in combination with cellular operation ......................................................................................... 29

Related documents........................................................................................................... 30

Revision history ................................................................................................................ 30

Contact .............................................................................................................................. 31

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1 Hardware description

1.1 Overview

LEA-M8S and LEA-M8T are standalone GNSS positioning modules featuring the high performance u-blox M8

positioning engine. 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 specific product features, see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2].

To determine which u-blox product best meets your needs, see the product selector tables on the u-blox

website.

1.2 Configuration

The configuration settings can be modified using UBX protocol configuration messages, more information see

the u-blox M8 Receiver Description Including Protocol Specification [3]. 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.

The configuration can be saved permanently in flash of the LEA-M8T receiver.

1.3 Connecting power

The LEA-M8S and LEA-M8T positioning modules have up to three power supply pins: VCC, V_BCKP and

VDD_USB.

1.3.1 VCC: Main Supply Voltage

The VCC pin provides the main supply voltage. During operation, the current drawn by the module can vary by

some orders of magnitude, especially if enabling low-power operation modes. For this reason, it is important

that the supply circuitry is able to support the peak power for a short time (see the LEA-M8S Data Sheet [1] and

the NEO/LEA-M8T Data Sheet [2] for detail specification).

When switching from backup mode to normal operation or at start-up, the LEA-M8S and LEA-M8T

modules must charge the internal capacitors in the core domain. In certain situations, this can result in a

significant current draw. For low power applications using Power Save and backup modes, it is

important that the power supply or low ESR capacitors at the module input can deliver this

current/charge.

Use a proper GND concept. Do not use any resistors or coils in the power line.

1.3.2 V_BCKP: Backup Supply Voltage

If the module supply has a power failure, the V_BCKP pin supplies the real-time clock (RTC) and battery backed

RAM (BBR). Use of valid time and the GNSS orbit data at start-up will improve the GNSS performance, i.e.

enables hot and warm starts. If no backup battery is connected, the module performs a cold start at power-up.

Avoid high resistance on the V_BCKP line: During the switch from main supply to backup supply, a

short current adjustment peak can cause high voltage drop on the pin with possible malfunctions.

If no backup supply voltage is available, connect the V_BCKP pin to VCC.

As long as the LEA-M8S / LEA-M8T module is supplied via the VCC, the backup battery is disconnected

from the RTC and the BBR to avoid unnecessary battery drain (see Figure 1). In this case, VCC supplies

power to the RTC and BBR.

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Figure 1: Backup battery and voltage (for exact pin orientation, see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data

Sheet [2])

1.3.3 VDD_USB: USB interface power supply

VDD_USB supplies the USB interface. If the USB interface is not used, the VDD_USB pin must be connected to

GND. For more information about correctly handling the VDD_USB pin, see section 1.4

1.3.4 VCC_RF: Output Voltage RF section

The VCC_RF pin can supply an active antenna or external LNA. For more information, see section 2.4.

1.3.5 V_ANT: Antenna supply

The V_ANT pin is available to provide antenna bias voltage to supply an optional external active antenna. For

more information, see section 2.4.

If not used, connect the V_ANT pin to GND.

1.4 Interfaces

1.4.1 UART

The LEA-M8S and LEA-M8T positioning modules include a Universal Asynchronous Receiver Transmitter (UART)

serial interface RxD/TxD, which supports configurable baud rates. The baud rates supported are specified in the

LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2]. The signal output and input levels are 0 V to

VCC. An interface based on RS232 standard levels (+/- 12 V) can be implemented using level shifters such as

Maxim MAX3232. Hardware handshake signals and synchronous operation are not supported.

1.4.2 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 Vista, and Windows 7 operating systems (also

Windows 8 compatible). These drivers are available at our website at www.u-blox.com

USB external components

The USB interface requires some external components to implement the physical characteristics required by the

USB 2.0 specification. These external components are shown in Figure 2 and listed in Table 1. To comply with

USB specifications, VBUS must be connected through an LDO (U1) to pin VDD_USB on the module.

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.

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USB bus powered is not supported.

Figure 2: USB Interface

Name Component Function Comments

U1 LDO Regulates VBUS (4.4 …5.25 V)

down to a voltage of 3.3 V.

Almost no current requirement (~1 mA)

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 Ω is recommended.

R11 Resistor 100 kΩ is recommended for USB self-powered setup. For bus-powered setup,

R11 can be ignored.

Table 1: Summary of USB external components

1.4.3 Display Data Channel (DDC)

An I2C compatible Display Data Channel (DDC) interface is available 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 M8 Receiver Description Including Protocol

Specification [3]. For bandwidth information, see the LEA-M8S Data Sheet [1]. For timing parameters, consult the

I2C-bus specification [8].

The u-blox M8 DDC interface supports serial communication with u-blox cellular modules. See the

specification of the applicable cellular module to confirm compatibility.

1.4.4 SPI (LEA-M8T ONLY)

An SPI interface is available for communication to a host CPU with LEA-M8T module.

SPI is not available in the default configuration, because its pins are shared with the UART and DDC

interfaces. The SPI interface can be enabled by connecting D_SEL to ground. For speed and clock

frequency, see the NEO/LEA-M8T Data Sheet [2]

1.4.5 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.

The TX-ready functionality can be enabled and configured by AT commands sent to the involved u-blox

cellular module supporting the feature. For more information, see the GPS Implementation and Aiding

Features in u-blox wireless modules [9].

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1.5 I/O pins

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 LEA-M8S and

LEA-M8T modules RESET_N is an input only.

RESET_N should be used only in critical situations to recover the system. The Real-Time Clock (RTC) will

also be reset and thus immediately afterwards the receiver cannot perform a Hot Start.

EXTINT: External interrupt

EXTINT is an external interrupt pin with fixed input voltage thresholds with respect to VCC (see the LEA-M8S

Data Sheet [1] or the NEO/LEA-M8T Data Sheet [2] for more information). It can be used for wake-up functions

in Power Save Mode on all u-blox M8 modules and for aiding. Leave open if unused.

SAFEBOOT_N

If the SAFEBOOT_N pin is “low” at start up, the u-blox M8 module starts in Safe Boot Mode and doesn’t begin

GNSS operation. The Safe Boot Mode can be used to recover from situations where the Flash has become

corrupted.

D_SEL: Interface select (LEA-M8T ONLY)

The D_SEL pin selects the available interfaces. SPI cannot be used simultaneously with UART/DDC.

If open, UART and DDC are available. If pulled low, the SPI interface is available. See the NEO/LEA-M8T Data

Sheet [2].

Antenna Short circuit detection

The LEA-M8S and LEA-M8T modules include internal short circuit antenna detection. For more information, see

section 2.4.

Antenna open circuit detection

The LEA-M8S and LEA-M8T 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 (antenna consumes current), while high means no external antenna

has been detected (no current drawn). This functionality is by default disabled. See section 2.4.2.

TIMEPULSE 1

A configurable time pulse signal is available with all u-blox M8 modules. By default, the time pulse signal is

configured to 1 pulse per second. For more information, see the u-blox M8 Receiver Description Including

Protocol Specification [3].

TIMEPULSE 2 (LEA-M8T only)

A configurable time pulse 2 signal is available on LEA-M8T module only. For more information see the u-blox M8

Receiver Description Including Protocol Specification [3].

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Electromagnetic interference on I/O lines

Any I/O signal line with a length greater than approximately 3 mm can act as an antenna and may pick up

arbitrary RF signals transferring them as noise into the GNSS receiver. This specifically applies to unshielded lines,

in which the corresponding GND layer is remote or missing entirely, and lines close to the edges of the printed

circuit board.

If, for example, a cellular signal radiates into an unshielded high-impedance line, it is possible to generate noise

in the order of volts and not only distort receiver operation but also damage it permanently.

On the other hand, noise generated at the I/O pins will emit from unshielded I/O lines. Receiver performance

may be degraded when this noise is coupled into the GNSS antenna (see Figure 19).

To avoid interference by improperly shielded lines, it is recommended to use resistors (e.g. R>20 Ω), ferrite beads

(e.g. BLM15HD102SN1) or inductors (e.g. LQG15HS47NJ02) on the I/O lines in series. These components should

be chosen with care because they will affect also the signal rise times.

Figure 3 shows an example of EMI protection measures on the RX/TX line using a ferrite bead. More information

can be found in section 4.3.

Figure 3: EMI Precautions

GNSS

Receiver

BLM15HD102SN1

>10mm

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2 Design

2.1 Pin description

Function PIN No I/O Description Remarks

Power VCC 6 I Supply Voltage Provide clean and stable supply.

GND 7, 13, 14,

15, 17

- Ground Assure a good GND connection to all GND pins of the

module

VCC_OUT 8 O Output Voltage (VCC) 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 GNSS signal input

from antenna

Use a controlled impedance transmission line of 50 Ω to

connect to RF_IN.

VCC_RF 18 O Output Voltage RF

section

Can be used to power external LNA or 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 Ω resistor in front of

V_ANT input to the Antenna Bias Voltage or VCC_RF

EXTINT1/

AADET_N

20 I Ext. Interrupt /Active

Antenna Detect

Ext. Interrupt Pin. Int. pull-up resistor to VCC./ Input pin for

optional antenna supervisor circuitry. Leave open if not used.

UART TxD (LEA-M8S) 3

TxD / SPI MISO

(LEA-M8T)

O Serial Port Communication interface can be programmed as TX Ready

for DDC interface. Leave open if not used.

TxD

SPI MISO

Serial Port if D_SEL =1(or open)

SPI MISO if D_SEL = 0

RxD (LEA-M8S) 4

RxD /SPI MOSI

(LEA-M8T)

I Serial Port

Serial port input with internal pull-up resistor to VCC. Leave

open if not used. Do not use external pull up resistor.

RxD

SPI MOSI

Serial Port if D_SEL =1(or open)

SPI MOSI if D_SEL = 0

USB USB_DM 25 I/O USB I/O line

USB2.0 bidirectional communication pin. Leave open if

unused. Implementations see section 1.4

USB_DP 26 I/O USB I/O line

System RESET_N 10 I Hardware Reset

(Active Low)

Leave open if not used. Do not drive high.

TIMEPULSE 1 28 O Timepulse 1 Configurable Timepulse signal (one pulse per second by

default). Leave open if not used.

SAFEBOOT_N / 12

TIMEPULSE 2

(LEA-M8T)

SAFEBOOT_N (LEA-M8S)

I/O Safeboot_N /

Timepulse 2

Configurable Timepulse signal. Must not be held LO during

start-up.

I/O Safeboot_N Must not be held LO during start-up

EXTINT0 27 I Ext. Interrupt Ext. Interrupt Pin. Int. pull-up resistor to VCC. Leave open if

unused.

SDA (LEA-M8S) 1

SDA /SPI CS_N

(LEA-M8T)

I/O

DDC Pins

DDC Data. Leave open if not used.

I/O

SDA

SPI CS_N

DDC Data if D_SEL =1 (or open)

SPI Chip Select if D_SEL = 0

SCL (LEA-M8S) 2

SCL / SPI CLK

(LEA-M8T)

I DDC Pins DDC Clock. Leave open if not used.

I/O

SCL

SPI CLK

DDC Clock if D_SEL =1 (or open)

SPI Clock if D_SEL = 0

D_SEL (LEA-M8T) 5

Reserved(LEA-M8S)

Interface Select

D_SEL = 0 -> SPI, D_SEL =1 (or open) -> DDC

- Reserved Leave open

Reserved 9, 21, 22,

- Reserved Leave open

Table 2: Pinout LEA-M8S / LEA-M8T

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2.2 Minimal design

This is a minimal setup for a GNSS receiver with a LEA-M8S / LEA-M8T module:

• Passive antenna used

• No backup battery

• UART for communication

Figure 4: LEA-M8S / LEA-M8T passive antenna design

For active antenna design, see section 2.4

2.3 Footprint and paste mask

Figure 5 describes the footprint and provides recommendations for the paste mask for the LEA-M8S and

LEA-M8T modules. These are recommendations only and not specifications. Note that the copper and solder

masks have the same size and position.

To improve the wetting of the half vias, reduce the amount of solder paste under the module and increase the

volume outside of the module by defining the dimensions of the paste mask to form a T-shape (or equivalent)

extending beyond the copper mask. For the stencil thickness, see Figure 6.

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17.0 mm [669 mil]

22.4 mm [881.9 mil]

1.0 mm

[39 mil]

0.8 mm

[31.5 mil]

2.45 mm

[96.5 mil]

1.1 mm

[43 mil]

3.0 mm

[118 mil]

2.15 mm

[84.5 mil]

0.8 mm

[31.5 mil]

Figure 5: LEA-M8S / LEA-M8T footprint

Figure 6: LEA-M8S / LEA-M8T paste mask

2.4 Antenna and Antenna supervision

2.4.1 Antenna design with passive antenna

A design using a passive antenna requires more attention to the layout of the RF section. Typically, a passive

antenna is located near electronic components; therefore, care should be taken to reduce electrical noise that

may interfere with the antenna performance. Passive antennas do not require a DC bias voltage and can be

directly connected to the RF input pin RF_IN. Sometimes they may also need a passive matching network to

match the impedance to 50 Ω.

Minimal setup with a good patch antenna

Figure 7 shows a minimal setup for a design with a good GNSS patch antenna.

Figure 7: Module design with passive antenna (for exact pin orientation see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T

Data Sheet [2])

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Setup for best performance with passive antenna

Figure 8 shows a design using an external LNA to increase the sensitivity for best performance with passive

antenna.

Figure 8: Module design with passive antenna and an external LNA (for exact pin orientation see the LEA-M8S Data Sheet [1]

and the NEO/LEA-M8T Data Sheet [2].)

The VCC_RF output can be used to supply the LNA with a filtered supply voltage.

For recommended parts, see Appendix

A standard GNSS LNA has enough bandwidth to amplify GPS / GLONASS and BeiDou signals.

2.4.2 Active antenna design

Active antennas have an integrated low-noise amplifier. Active antennas require a power supply that will

contribute to the total GNSS system power consumption budget with additional 5 to 20 mA typically.

If the customers do not want to make use of the internal antenna supervisor and the supply voltage of the LEA-

M8S / LEA-M8T module matches the supply voltage of the antenna (e.g. 3.0 V), they can use the filtered supply

voltage VCC_RF output to supply the antenna (See Figure 9). This design is used for modules in combination

with active antenna.

In case of different supply voltage, use a filtered external supply, see Figure 10.

Active antenna design using VCC_RF pin to supply the active antenna

Figure 9: Active antenna design, external supply from VCC_RF (for exact pin orientation see the LEA-M8S Data Sheet [1])

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Active antenna design powered from external supply

Figure 10 shows a design with direct externally powered active antenna.

This circuit has to be used if the active antenna has a different supply voltage than the VCC_RF (for example if a

5 V active antenna is used).

Figure 10: Active antenna design, direct external supply (for exact pin orientation see the LEA-M8S Data Sheet [1] and the

NEO/LEA-M8T Data Sheet [2])

For recommended parts, see Appendix.

In case VCC_RF voltage does not match with the antenna supply voltage, use a filtered external supply

as shown in Figure 10.

Antenna design with active antenna using antenna supervisor

An active antenna supervisor provides the means to check the antenna for open and short circuits and to shut

off the antenna supply if a short circuit is detected. The Antenna Supervisor is configured using serial port UBX

binary protocol message. Once enabled, the active antenna supervisor produces status messages, reporting in

NMEA and/or UBX binary protocol. These indicate the particular state of the antenna supervisor shown in the

state diagram (see Figure 11).

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The current active antenna status can be determined by polling the UBX-MON-HW monitor command. If an

antenna is connected, the initial state after power-up is “Active Antenna OK.”

Super-

vision

Active

Antenna

Open

Circuit

detected

Short

Circuit

detected

Powerup

Events AADET0_N

User controlled events

Disable Supervision

Enable Supervision

Short Circuit

detected

Disable

Supervision

Antenna

connected

Short Circuit

detected

open circuit

detected,given

OCD enabled

Periodic

reconnection

attempts

Figure 11: State diagram of active antenna supervisor

The module firmware supports an active antenna supervisor circuit, which is connected to the AADET_N pin. For

an example of an open circuit detection circuit, see Figure 14. High on AADET_N means that an external

antenna is not connected.

Status reporting

At startup, and on every change of the antenna supervisor configuration, the LEA-M8S and LEA-M8T modules

will output an NMEA ($GPTXT) or UBX (INF-NOTICE) message with the internal status of the antenna supervisor

(disabled, short detection only, enabled).

Abbreviation Description

AC Antenna Control (e.g. the antenna will be switched on/ off controlled by the GNSS receiver)

SD Short Circuit Detection Enabled

SR Short Circuit Recovery Enabled

OD Open Circuit Detection Enabled

PdoS Power Down on short

Table 3: Active Antenna Supervisor Message on startup (UBX binary protocol)

To activate the antenna supervisor use the UBX-CFG-ANT message. For further information, refer to the

u-blox M8 Receiver Description Including Protocol Specification [3].

Similar to the antenna supervisor configuration, the status of the antenna supervisor will be reported in an

NMEA ($GPTXT) or UBX (INF-NOTICE) message at start-up and on every change.

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Message Description

ANTSTATUS=DONTKNOW Active antenna supervisor is not configured and deactivated.

ANTSTATUS=OK Active antenna connected and powered

ANTSTATUS=SHORT Antenna short

ANTSTATUS=OPEN Antenna not connected or antenna defective

Table 4: Active antenna supervisor message on startup (NMEA protocol)

Module design with active antenna, short circuit protection / detection

If a suitably dimensioned R_BIAS series resistor is placed in front of the V_ANT pin, a short circuit can be

detected in the antenna supply. The detection happens inside the u-blox M8 module, after which the antenna

supply voltage will be immediately shut down. Afterwards, periodic attempts to re-establish antenna power are

made by default.

An internal switch (under control of the receiver) can turn off the supply to the external antenna whenever it is

not needed. This feature helps to reduce power consumption in power save mode.

To configure the antenna supervisor use the UBX-CFG-ANT message. For further information, see the

u-blox M8 Receiver Description Including Protocol Specification [3].

Short circuits on the antenna input without limitation (R_BIAS) of the current can result in

permanent damage to the receiver! Therefore, it is mandatory to implement an R_BIAS in all

risk applications, such as situations where the antenna can be disconnected by the end-user or

that have long antenna cables.

In case VCC_RF voltage does not match with the antenna supply voltage, use a filtered external supply

as shown in Figure 13.

Supply from VCC_RF

Figure 12 shows an active antenna supplied from the LEA-M8S and LEA-M8T modules.

LEA-M8S and LEA-M8T modules includes a built in antenna bias supply for nominal 3V antennas enabled by

linking the filtered VCC_RF supply output pin to the V_ANT antenna supply input pin with a 10 Ohm resistor in

series. The module then controls the power supply to the antenna, applying power whenever the receiver is

active and removing power during power-save idle times and if a short-circuit is detected. Short-circuit is

detected if the voltage at the antenna supply falls close to zero and is indicated as an alarm in message MON-

Figure 12: Module design with active antenna, internal supply from VCC_RF (for exact pin orientation see the LEA-M8S Data

Sheet [1] and the NEO/LEA-M8T Data Sheet [2].)

For recommended parts, see Appendix.

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External supply

Figure 13 shows an externally powered active antenna design.

Since the external bias voltage is fed into the most sensitive part of the receiver (i.e. the RF input), this supply

should be free of noise. Usually, low frequency analog noise is less critical than digital noise of spurious

frequencies with harmonics up to the GPS/QZSS band of 1.575 GHz, GLONASS band of 1.602 GHz and BeiDou

band at 1.561 GHz. Therefore, it is not recommended to use digital supply nets to feed the V_ANT pin.

Figure 13: Module design with active antenna, external supply (for exact pin orientation see the LEA-M8S Data Sheet [1] and

the NEO/LEA-M8T Data Sheet [2])

Antenna supervision with open circuit detection (OCD)

Optionally the AADET_N pin may be reassigned to antenna supervision allowing an external circuit to indicate to

the module that the antenna is open-circuit. This condition is then reported by the module in message MON-

HW. Calculate the threshold current using Equation 1.

Figure 14: Schematic of open circuit detection (for exact pin orientation see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T

Data Sheet [2].)

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RFVcc

Rbias

•













Equation 1: Calculation of threshold current for open circuit detection

If the antenna supply voltage is not derived from VCC_RF, do not exceed the maximum voltage rating of

AADET_N.

For recommended parts, see Appendix

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3 Migration to u-blox M8 modules

3.1 Migrating u-blox 6 designs to a u-blox M8 module

u-blox is committed to ensuring that products in the same form factor are backwards compatible over several

technology generations. Utmost care has been taken to ensure there is no negative impact on function or

performance and to make u-blox M8 modules as fully compatible as possible with previous generations modules.

If using BeiDou, check the bandwidth of the external RF components and the antenna. For information about

power consumption, see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2]. It is highly advisable

that customers consider a design review with the u-blox support team to ensure the compatibility of key

functionalities.

3.2 Hardware migration LEA-6N -> LEA-M8S

LEA-6N LEA-M8S Remarks for Migration

Pin Name Typical Assignment Pin Name Typical Assignment

1 SDA DDC Data SDA DDC Data No difference

2 SCL DDC Clock SCL DDC Clock No difference

3 TxD Serial Port TxD Serial Port No difference

4 RxD Serial Port RxD Serial Port No difference

5 NC Not Connected Reserved Not Connected No difference

6 VCC Supply voltage VCC Supply voltage No difference

7 GND Ground (digital) GND Ground (digital) No difference

8 VCC_OUT Output voltage VCC_OUT Output voltage No difference

9 NC Not Connected Reserved Not Connected No difference

10 RESET_N External Reset RESET_N External Reset No difference

11 V_BCKP Backup voltage supply V_BCKP Backup voltage supply

If this was connected to GND

on u-blox 6 module, OK to

do the same on u-blox M8.

12 Safeboot_N Do not drive low Safeboot_N Do not drive low No difference

13 GND Ground GND Ground No difference

14 GND Ground GND Ground No difference

15 GND Ground GND Ground No difference

16 RF_IN GNSS signal input RF_IN GNSS signal input No difference

17 GND Ground GND Ground No difference

18 VCC_RF Output Voltage RF section VCC_RF Output Voltage RF section No difference

19 V_ANT Antenna Bias voltage V_ANT Antenna Bias voltage No difference

20 AADET_N Active Antenna Detect AADET_N Active Antenna Detect No difference

21 Reserved Not Connected Reserved Not Connected No difference

22 Reserved Not Connected Reserved Not Connected No difference

23 Reserved Not Connected Reserved Not Connected No difference

24 VDD_USB USB Supply VDD_USB USB Supply No difference

25 USB_DM USB Data USB_DM USB Data No difference

26 USB_DP USB Data USB_DP USB Data No difference

27 EXTINT0 External Interrupt Pin EXTINT0 External Interrupt Pin No difference

28 TIMEPULSE Timepulse (1PPS) TIMEPULSE Timepulse (1PPS) No difference

Table 5: Pin-out comparison LEA-6N vs. LEA-M8S

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3.3 Hardware migration LEA-6T -> LEA-M8T

LEA-6T LEA-M8T Remarks for Migration

Pin Name Typical Assignment Pin Name Typical Assignment

1 SDA DDC Data SDA DDC Data No difference

2 SCL DDC Clock SCL DDC Clock No difference

3 TxD Serial Port TxD Serial Port No difference

4 RxD Serial Port RxD Serial Port No difference

5 NC Not Connected D_SEL D_SEL =1(or open) Do not drive low

6 VCC Supply voltage VCC Supply voltage No difference

7 GND Ground (digital) GND Ground (digital) No difference

8 VCC_OUT Output voltage VCC_OUT Output voltage No difference

9 TIMEPULSE2 2nd Timepulse Not Connected Reserved

Time Pulse 2 is now

available on pin 12

(Safeboot_N / Time Pulse 2)

10 RESET_N External Reset RESET_N External Reset No difference

11 V_BCKP Backup voltage supply V_BCKP Backup voltage supply

If this was connected to GND

on u-blox 6 module, OK to do

the same on u-blox M8.

12 Safeboot_N Safeboot_N Safeboot_N/

TIMEPULSE2 Safeboot_N /Timepulse 2 Must not be held LO during

start-up.

13 GND Ground GND Ground No difference

14 GND Ground GND Ground No difference

15 GND Ground GND Ground No difference

16 RF_IN GNSS signal input RF_IN GNSS signal input No difference

17 GND Ground GND Ground No difference

18 VCC_RF Output Voltage RF section VCC_RF Output Voltage RF

section No difference

19 V_ANT Antenna Bias voltage V_ANT Antenna Bias voltage No difference

20 AADET_N Active Antenna Detect EXTINT1/AADET_N External Interrupt Pin/

Active Antenna Detect

21 Reserved Not Connected Reserved Not Connected No difference

22 Reserved Not Connected Reserved Not Connected No difference

23 Reserved Not Connected Reserved Not Connected No difference

24 VDD_USB USB Supply VDD_USB USB Supply No difference

25 USB_DM USB Data USB_DM USB Data No difference

26 USB_DP USB Data USB_DP USB Data No difference

27 EXTINT0 External Interrupt Pin EXTINT0 External Interrupt Pin No difference

28 TIMEPULSE1 Timepulse (1PPS) TIMEPULSE1 Timepulse (1PPS) No difference

Table 6: Pin-out comparison LEA-6T vs. LEA-M8T

3.4 Software migration

For overall description of the module software operation, see the u-blox M8 Receiver Description

Including Protocol Specification [3].

All features requiring a flash on LEA-6N are not supported on LEA-M8S. (AssistNow offline / save config)

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4 Product handling

4.1 Packaging, shipping, storage and moisture preconditioning

For information pertaining to reels and tapes, Moisture Sensitivity levels (MSL), shipment and storage

information, as well as drying for preconditioning see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data

Sheet [2].

Population of Modules

When populating the modules, make sure that the pick and place machine is aligned to the copper pins

of the module and not on the module edge.

4.2 Soldering

Soldering paste

Use of “No Clean” soldering paste is strongly recommended, as it does not require cleaning after the soldering

process has taken place. The paste listed in the example below meets these criteria.

Soldering Paste: OM338 SAC405 / Nr.143714 (Cookson Electronics)

Alloy specification: Sn 95.5/ Ag 4/ Cu 0.5 (95.5% Tin/ 4% Silver/ 0.5% Copper)

Melting Temperature: 217 °C

Stencil Thickness: See Figure 6.

The final choice of the soldering paste depends on the approved manufacturing procedures.

The paste-mask geometry for applying soldering paste should meet the recommendations.

The quality of the solder joints on the connectors (’half vias’) should meet the appropriate IPC

specification.

Reflow soldering

A convection type-soldering oven is highly recommended over the infrared type radiation oven.

Convection heated ovens allow precise control of the temperature, and all parts will heat up evenly, regardless

of material properties, thickness of components and surface color.

As a reference, see the “IPC-7530 Guidelines for temperature profiling for mass soldering (reflow and wave)

processes”, published in 2001.

Preheat phase

During the initial heating of component leads and balls, residual humidity will be dried out. Note that this

preheat phase will not replace prior baking procedures.

• Temperature rise rate: max. 3 °C/s. If the temperature rise is too rapid in the preheat phase it may cause

excessive slumping.

• Time: 60 – 120 s. If the preheat is insufficient, rather large solder balls tend to be generated. Conversely, if

performed excessively, fine balls and large balls will be generated in clusters.

• End Temperature: 150 – 200 °C. If the temperature is too low, non-melting tends to be caused in areas

containing large heat capacity.

Heating/ Reflow phase

The temperature rises above the liquidus temperature of 217°C. Avoid a sudden rise in temperature as the slump

of the paste could become worse.

• Limit time above 217 °C liquidus temperature: 40 – 60 s

• Peak reflow temperature: 245 °C

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Cooling phase

A controlled cooling avoids negative metallurgical effects (solder becomes more brittle) of the solder and

possible mechanical tensions in the products. Controlled cooling helps to achieve bright solder fillets with a good

shape and low contact angle.

• Temperature fall rate: max 4 °C/s

To avoid falling off, the u-blox M8 GNSS module should be placed on the topside of the motherboard

during soldering.

The final soldering temperature chosen at the factory depends on additional external factors like choice of

soldering paste, size, thickness and properties of the baseboard, etc. Exceeding the maximum soldering

temperature in the recommended soldering profile may permanently damage the module.

Figure 15: Recommended soldering profile

u-blox M8 modules must not be soldered with a damp heat process.

Optical inspection

After soldering the u-blox M8 module, consider an optical inspection step to check whether:

• The module is properly aligned and centered over the pads

• All pads are properly soldered

• No excess solder has created contacts to neighboring pads, or possibly to pad stacks and vias nearby

Cleaning

In general, cleaning the populated modules is strongly discouraged. Residues underneath the modules cannot be

easily removed with a washing process.

• Cleaning with water will lead to capillary effects where water is absorbed in the gap between the baseboard

and the module. The combination of residues of soldering flux and encapsulated water leads to short circuits

or resistor-like interconnections between neighboring pads.

• Cleaning with alcohol or other organic solvents can result in soldering flux residues flooding into the two

housings, areas that are not accessible for post-wash inspections. The solvent will also damage the sticker

and the ink-jet printed text.

• Ultrasonic cleaning will permanently damage the module, in particular the quartz oscillators.

The best approach is to use a “no clean” soldering paste and eliminate the cleaning step after the soldering.

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Repeated reflow soldering

Only single reflow soldering processes are recommended for boards populated with u-blox M8 modules. u-blox

M8 modules should not be submitted to two reflow cycles on a board populated with components on both sides

in order to avoid upside down orientation during the second reflow cycle. In this case, the module should always

be placed on that side of the board, which is submitted into the last reflow cycle. The reason for this (besides

others) is the risk of the module falling off due to the significantly higher weight in relation to other

components.

Two reflow cycles can be considered by excluding the above described upside down scenario and taking into

account the rework conditions described in section 4.

Repeated reflow soldering processes and soldering the module upside down are not recommended.

Wave soldering

Baseboards with combined through-hole technology (THT) components and surface-mount technology (SMT)

devices require wave soldering to solder the THT components. Only a single wave soldering process is

encouraged for boards populated with u-blox M8 modules.

Hand soldering

Hand soldering is allowed. Use a soldering iron temperature-setting equivalent to 350 °C. Place the module

precisely on the pads. Start with a cross-diagonal fixture soldering (e.g. pins 1 and 15), and then continue from

left to right.

Rework

The u-blox M8 module can be unsoldered from the baseboard using a hot air gun. When using a hot air gun for

unsoldering the module, a maximum of one reflow cycle is allowed. In general, we do not recommend using a

hot air gun because this is an uncontrolled process and might damage the module.

Attention: use of a hot air gun can lead to overheating and severely damage the module.

Always avoid overheating the module.

After the module is removed, clean the pads before placing and hand soldering a new module.

Never attempt a rework on the module itself, e.g. replacing individual components. Such

actions immediately terminate the warranty.

In addition to the two reflow cycles, manual rework on particular pins by using a soldering iron is allowed.

Manual rework steps on the module can be done several times.

Conformal coating

Certain applications employ a conformal coating of the PCB using HumiSeal® or other related coating products.

These materials affect the HF properties of the GNSS module and it is important to prevent them from flowing

into the module. The RF shields do not provide 100% protection for the module from coating liquids with low

viscosity; therefore, care is required in applying the coating.

Conformal Coating of the module will void the warranty.

Casting

If casting is required, use viscose or another type of silicon pottant. The OEM is strongly advised to qualify such

processes in combination with the u-blox M8 module before implementing this in the production.

Casting will void the warranty.

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Grounding metal covers

Attempts to improve grounding by soldering ground cables, wick or other forms of metal strips directly onto the

EMI covers is done at the customer’s own risk. The numerous ground pins should be sufficient to provide

optimum immunity to interferences and noise.

u-blox makes no warranty for damages to the u-blox M8 module caused by soldering metal cables or

any other forms of metal strips directly onto the EMI covers.

Use of ultrasonic processes

Some components on the u-blox M8 module are sensitive to Ultrasonic Waves. Use of any Ultrasonic Processes

(cleaning, welding etc.) may cause damage to the GNSS Receiver.

u-blox offers no warranty against damages to the u-blox M8 module caused by any Ultrasonic Processes.

4.3 EOS/ESD/EMI precautions

When integrating GNSS positioning modules into wireless systems, careful consideration must be given to

electromagnetic and voltage susceptibility issues. Wireless systems include components that can produce

Electrical Overstress (EOS) and Electro-Magnetic Interference (EMI). CMOS devices are more sensitive to such

influences because their failure mechanism is defined by the applied voltage, whereas bipolar semiconductors

are more susceptible to thermal overstress. The following design guidelines are provided to help in designing

robust yet cost effective solutions.

To avoid overstress damage during production or in the field it is essential to observe strict

EOS/ESD/EMI handling and protection measures.

To prevent overstress damage at the RF_IN of your receiver, never exceed the maximum input

power (see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2]).

Electrostatic discharge (ESD)

Electrostatic discharge (ESD) is the sudden and momentary electric current that flows between

two objects at different electrical potentials caused by direct contact or induced by an

electrostatic field. The term is usually used in the electronics and other industries to describe

momentary unwanted currents that may cause damage to electronic equipment.

ESD handling precautions

ESD prevention is based on establishing an Electrostatic Protective Area (EPA). The EPA can be a small working

station or a large manufacturing area. The main principle of an EPA is that there are no highly charging materials

near ESD sensitive electronics, all conductive materials are grounded, workers are grounded, and charge build-up

on ESD sensitive electronics is prevented. International standards are used to define typical EPA and can be

obtained for example from International Electrotechnical Commission (IEC) or American National Standards

Institute (ANSI).

GNSS positioning modules are sensitive to ESD and require special precautions when handling. Particular care

must be exercised when handling patch antennas, due to the risk of electrostatic charges. In addition to

standard ESD safety practices, the following measures should be taken into account whenever handling the

receiver.

• Unless there is a galvanic coupling between the local GND (i.e. the

work table) and the PCB GND, then the first point of contact when

handling the PCB must always be between the local GND and PCB

GND.

• Before mounting an antenna patch, connect ground of the device

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• When handling the RF pin, do not come into contact with any

charged capacitors and be careful when contacting materials that

can develop charges (e.g. patch antenna ~10 pF, coax cable ~50 –

80 pF/m, soldering iron, …)

• To prevent electrostatic discharge through the RF input, do not

touch any exposed antenna area. If there is any risk that such

exposed antenna area is touched in non ESD protected work area,

implement proper ESD protection measures in the design.

• When soldering RF connectors and patch antennas to the receiver’s

RF pin, make sure to use an ESD safe soldering iron (tip).

Failure to observe these precautions can result in severe damage to the GNSS module!

ESD protection measures

GNSS positioning modules are sensitive to Electrostatic Discharge (ESD). Special precautions

are required when handling.

For more robust designs, employ additional ESD protection measures. Using an LNA with appropriate

ESD rating can provide enhanced GNSS performance with passive antennas and increases ESD

protection.

Most defects caused by ESD can be prevented by following strict ESD protection rules for production and

handling. When implementing passive antenna patches or external antenna connection points, then additional

ESD measures can also avoid failures in the field as shown in Figure 16.

Small passive antennas (<2 dBic and

performance critical)

Passive antennas (>2 dBic or performance

sufficient)

Active antennas

RF_IN

GNSS

Receiver

LNA

RF_IN

GNSS

Receiver

RF_IN

GNSS

Receiver

LNA with appropriate ESD rating

Figure 16: ESD Precautions

Protection measure A is preferred because it offers the best GNSS performance and best level of ESD

protection.

Electrical Overstress (EOS)

Electrical Overstress (EOS) usually describes situations when the maximum input power exceeds the maximum

specified ratings. EOS failure can happen if RF emitters are close to a GNSS receiver or its antenna. EOS causes

damage to the chip structures. If the RF_IN is damaged by EOS, it is hard to determine whether the chip

structures have been damaged by ESD or EOS.

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EOS protection measures

For designs with GNSS positioning modules and wireless (e.g. GSM/GPRS) transceivers in close proximity,

ensure sufficient isolation between the wireless and GNSS antennas. If wireless power output causes the

specified maximum power input at the GNSS RF_IN to be exceeded, employ EOS protection measures to

prevent overstress damage.

For robustness, EOS protection measures, as shown in Figure 17, are recommended for designs combining

wireless communication transceivers (e.g. GSM, GPRS) and GNSS in the same design or in close proximity.

Small passive antennas (<2 dBic and

performance critical)

Passive antennas (>2 dBic or

performance sufficient)

Active antennas (without internal filter which need the

module antenna supervisor circuits)

RF_IN

GNSS

Receiver

LNA

GPS

Bandpass

Filtler

RF_IN

GNSS

Receiver

GPS

Bandpass

Filtler

LNA with appropriate ESD rating and

maximum input power

GNSS Band pass Filter: SAW or

Ceramic with low insertion loss and

appropriate ESD rating

Figure 17: EOS and ESD Precautions

Electromagnetic interference (EMI)

Electromagnetic interference (EMI) is the addition or coupling of energy causing a spontaneous reset of the

GNSS receiver or resulting in unstable performance. In addition to EMI degradation due to self-jamming (see

section 1.5) any electronic device near the GNSS receiver can emit noise that can lead to EMI disturbances or

damage.

The following elements are critical regarding EMI:

• Unshielded connectors (e.g. pin rows etc.)

• Weakly shielded lines on PCB (e.g. on top or bottom layer and especially at the border of a PCB)

• Weak GND concept (e.g. small and/or long ground line connections)

EMI protection measures are recommended when RF emitting devices are near the GNSS receiver. To minimize

the effect of EMI a robust grounding concept is essential. To achieve electromagnetic robustness follow the

standard EMI suppression techniques.

http://www.murata.com/products/emc/knowhow/index.html

http://www.murata.com/products/emc/knowhow/pdf/4to5e.pdf

Improved EMI protection can be achieved by inserting a resistor or better yet a ferrite bead or an inductor (see

Table 7) into any unshielded PCB lines connected to the GNSS receiver. Place the resistor as close as possible to

the GNSS receiver pin.

Alternatively, feed-thru capacitors with good GND connection can be used to protect e.g. the VCC supply pin

against EMI. A selection of feed-thru capacitors are listed in Table 7.

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4.4 Applications with cellular modules

GSM uses power levels up to 2 W (+33 dBm). Consult the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data

Sheet [2] for the absolute maximum power input at the GNSS receiver.

See the GPS Implementation and Aiding Features in u-blox wireless modules [9].

Isolation between GNSS and GSM antenna

In a handheld type design, an isolation of approximately 20 dB can be reached with careful placement of the

antennas. If such isolation cannot be achieved, e.g. in the case of an integrated GSM/GNSS antenna, an

additional input filter is needed on the GNSS side to block the high energy emitted by the GSM transmitter.

Examples of these kinds of filters would be the SAW Filters from Epcos (B9444 or B7839) or Murata.

Increasing interference immunity

Interference signals come from in-band and out-band frequency sources.

In-band interference

With in-band interference, the signal frequency is very close to the GNSS constellation frequency used, e.g. GPS

frequency of 1575 MHz (see Figure 18). Such interference signals are typically caused by harmonics from

displays, micro-controller, bus systems, etc.

1525 1550 1625

GPS input filter

characteristics

1575 1600

-110

J ammi n

g signal

1525 1550 1625

Frequency [MHz]

Power [dBm]

GPS input filter

characteristics

1575 1600

J ammi n g

signal

GPS

signals

GPS Carrier

1575.4 MHz

Figure 18: In-band interference signals

Figure 19: In-band interference sources

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Measures against in-band interference include:

• Maintaining a good grounding concept in the design

• Shielding

• Layout optimization

• Filtering

• Placement of the GNSS antenna

• Adding a CDMA, GSM, WCDMA band pass filter before handset antenna

Out-band interference

Out-band interference is caused by signal frequencies that are different from the GNSS carrier (see Figure 20).

The main sources are wireless communication systems such as GSM, CDMA, WCDMA, Wi-Fi, BT, etc.

0500 1000 1500 2000

GPS input filter

characteristics

-110

0500 1500 2000

Frequency [MHz]

GSM

900

GSM

1800

GSM

1900

Power [dBm]

GPS input filter

characteristics

GPS

1575

-110

GPS

signals

GSM

950

Figure 20: Out-band interference signals

Measures against out-band interference include maintaining a good grounding concept in the design and

adding a SAW or band pass ceramic filter (as recommend in section 4) into the antenna input line to the GNSS

receiver (see Figure 21).

Figure 21: Measures against in-band interference

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Appendix

Recommended parts

Recommended parts are selected on data sheet basis only. Other components may also be used.

Manufacturer Part ID Remarks Parameters to consider

Diode ON

Semiconductor

ESD9R3.3ST5G Standoff Voltage>3.3 V Low Capacitance < 0.5 pF

ESD9L3.3ST5G Standoff Voltage>3.3 V Standoff Voltage > Voltage for active antenna

ESD9L5.0ST5G Standoff Voltage>5 V Low Inductance

SAW TDK/ EPCOS B8401: B39162-B8401-P810 GPS+GLONASS High attenuation

TDK/ EPCOS B3913: B39162B3913U410 GPS+GLONASS+BeiDou For automotive application

TDK/ EPCOS B4310: B39162B4310P810 GPS+GLONASS Compliant to the AEC-Q200 standard

ReyConns NDF9169 GPS+ BeiDou Low insertion loss, Only for mobile application

muRata SAFFB1G56KB0F0A GPS+GLONASS+BeiDou Low insertion loss, Only for mobile application

muRata SAFEA1G58KB0F00 GPS+GLONASS Low insertion loss, only for mobile application

muRata SAFEA1G58KA0F00 GPS+GLONASS High attenuation, only for mobile application

muRata SAFFB1G58KA0F0A GPS+GLONASS High attenuation, only for mobile application

muRata

SAFFB1G58KB0F0A

GPS+GLONASS

Low insertion loss, Only for mobile application

TAI-SAW TA1573A GPS+GLONASS Low insertion loss

TAI-SAW TA1343A GPS+GLONASS+BeiDou Low insertion loss

TAI-SAW TA0638A GPS+GLONASS+BeiDou Low insertion loss

LNA JRC NJG1143UA2 LNA Low noise figure, up to 15 dBm RF input

power

Avago ALM-GN001 LNA Low noise figure, with pre-LNA filter,

concurrent GNSS

Avago ALM-GN002 LNA Very low noise figure, with post-LNA filter,

concurrent GNSS

Inductor Murata LQG15HS27NJ02 L, 27 nH Impedance @ freq GNSS > 500 Ω

Capacitor Murata GRM1555C1E470JZ01 C, 47 pF DC-block

Ferrite

Bead

Murata BLM15HD102SN1 FB High IZI @ fGSM

Feed thru

Capacitor

for Signal

Murata NFL18SP157X1A3 Monolithic Type For data signals, 34 pF load capacitance

NFA18SL307V1A45 Array Type For data signals, 4 circuits in 1 package

Feed thru

Capacitor

Murata NFM18PC ….

NFM21P….

0603 2A

0805 4A

Rs < 0.5

Ω

Resistor 10 Ω ± 10%, min 0.250 W R

bias

560 Ω ± 5% R2

100 kΩ ± 5% R3, R4

Table 7: Recommended parts

Recommended antennas

Manufacturer

Order No. Comments

Hirschmann (www.hirschmann-car.com) GLONASS 9 M GPS+GLONASS active

Taoglas (www.taoglas.com ) AA.160.301111 36*36*4 mm, 3-5V 30mA active

Taoglas (www.taoglas.com ) AA.161.301111 36*36*3 mm, 1.8 to 5.5V / 10mA at 3V active

INPAQ (www.inpaq.com.tw) B3G02G-S3-01-A 2.7 to 3.9 V / 10 mA active

Amotech (www.amotech.co.kr) B35-3556920-2J2 35x35x3 mm GPS+GLONASS passive

Amotech (www.amotech.co.kr) A25-4102920-2J3 25x25x4 mm GPS+GLONASS passive

Amotech (www.amotech.co.kr) A18-4135920-AMT04 18x18x4 mm GPS+GLONASS passive

Amotech (www.amotech.co.kr) Amotech AGA363913-

S0-A1

GPS+GLONASS+ BeiDou active

INPAQ (www.inpaq.com.tw) ACM4-5036-A1-CC-S 5.2 x 3.7 x 0.7 mm GPS+GLONASS passive

Additional antenna Manufacturer: Allis Communications, Tallysman Wireless

Table 8: Recommend antenna

LEA-M8S / LEA-M8T - Hardware Integration Manual

UBX-13003140 - R08 Production Information Appendix

Page 29 of 31

A.1 Design-in recommendations in combination with cellular operation

Product

Receiver Chain Cellular and GNSS

Simultaneous operation

Family

Variant

Antenna

SAW LNA

On-chip LNA

SAW

Passive GNSS

Antenna

Active GNSS

Antenna

SAW

2G cellular

3G/4G cellular

2G/3G/4G

cellular

MAX-6 Any • •



NEO-6 Any • •



LEA-6 Any • •



EVA-7 M •



MAX-7

C •



W •



Q •



NEO-7

N • •



M •



P • •



EVA-M8 M •



MAX-M8

C •



W •



Q •



NEO-M8

N • •



M •



Q • •



T • •



LEA-M8 S • •



T • •



PAM-7 Q • • • •



CAM-M8 C • • •



Q • • •



• = integrated  = optimal performance

Table 9: Combinations of u-blox GNSS modules with different cellular technologies (2G/3G/4G).

See the GPS Implementation and Aiding Features in u-blox wireless modules [9].

LEA-M8S / LEA-M8T - Hardware Integration Manual

UBX-13003140 - R08 Production Information Appendix

Page 30 of 31

LEA M8S / M8T Hardware Integration Manual (UBX 13003140)

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