Xsens MTi-1, MTi-2, MTi-3, MTi-7, MTi-1-8A7G6 Integration Manual

Xsens Technologies B.V.

Xsens North America, Inc.

Pantheon 6a

P.O. Box 559

7500 AN Enschede

The Netherlands

phone [phone]

fax [phone]

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internet www.xsens.com

10557 Jefferson Blvd,

Suite C

CA-90232 Culver City

USA

phone [phone]

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internet www.xsens.com

Document MT1503P, Revision A, 5 Apr 2018

MTi 1-series

Hardware Integration Manual

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Hardware Integration Manual MTi 1-series

Revisions

Revision

Date

By

Changes

A

05 Apr 2018

RGI

Initial release

© 2005-2018, Xsens Technologies B.V. All rights reserved. Information in this document is subject to
change without notice. Xsens, MVN, MotionGrid, MTi, MTx and Awinda are registered trademarks or
trademarks of Xsens Technologies B.V. and/or its parent, subsidiaries and/or affiliates in The
Netherlands, the USA and/or other countries. All other trademarks are the property of their respective
owners.

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Hardware Integration Manual MTi 1-series

Table of Contents

1 GENERAL INFORMATION ................................................................................................................... 1

2 POWER SUPPLY ................................................................................................................................ 2

2.1 MAIN SUPPLY VOLTAGE (VDDIO) .......................................................................................................... 2

2.2 ANALOG SUPPLY VOLTAGE (VDDA) ........................................................................................................ 2

2.3 SINGLE POWER SUPPLY CONFIGURATION ................................................................................................... 2

2.4 POWER SUPPLY SPECIFICATIONS ............................................................................................................. 3

3 INTERFACES ...................................................................................................................................... 4

3.1 PIN CONFIGURATION .......................................................................................................................... 4

3.2 COMMUNICATION TO HOST .................................................................................................................. 4

3.2.1 PSEL serial host communication interface selection ................................................................. 5

3.2.2 I2C ....................................................................................................................................... 6

3.2.3 SPI ....................................................................................................................................... 7

3.2.4 UART ................................................................................................................................... 7

3.3 GNSS RECEIVER AND BAROMETER INTERFACE............................................................................................. 8

3.4 I/O PINS ......................................................................................................................................... 9

3.4.1 Reset ................................................................................................................................... 9

3.4.2 SYNC_IN .............................................................................................................................. 9

3.5 DNC/RESERVED PINS ....................................................................................................................... 9

4 DESIGN ........................................................................................................................................... 10

4.1 PCB LAYOUT .................................................................................................................................. 10

4.1.1 Frames of reference used in MTi 1-series .............................................................................. 10

4.1.2 Origin of measurements ...................................................................................................... 11

4.2 MECHANICAL STRESS ........................................................................................................................ 11

4.2.1 Pushbutton contacts ........................................................................................................... 11

4.2.2 Anchor points ..................................................................................................................... 12

4.2.3 Vibrations .......................................................................................................................... 13

4.2.4 Heat .................................................................................................................................. 13

4.2.5 Sockets .............................................................................................................................. 13

4.3 MAGNETOMETER ............................................................................................................................ 13

4.3.1 Ferromagnetic materials ..................................................................................................... 13

4.3.2 High currents ..................................................................................................................... 13

4.4 FOOTPRINT .................................................................................................................................... 14

5 PACKAGING .................................................................................................................................... 15

5.1 TRAY PACKAGING INFORMATION .......................................................................................................... 15

5.2 REEL PACKAGING INFORMATION ........................................................................................................... 16

5.3 PACKAGE DRAWING .......................................................................................................................... 17

6 HANDLING ...................................................................................................................................... 18

6.1 REFLOW SPECIFICATION ..................................................................................................................... 18

6.2 ULTRASONIC PROCESSES .................................................................................................................... 18

6.3 ELECTROSTATIC DISCHARGE (ESD) ........................................................................................................ 19

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List of Tables

Table 1: MTi 1-series latest generation ........................................................................................................ 1

Table 2: MTi 1-series previous generation .................................................................................................... 1

Table 3: Maximum operating voltage ratings ................................................................................................ 3

Table 4: Host communication interfaces specifications.................................................................................. 4

Table 5: Serial host interface selection ......................................................................................................... 5

Table 6: List of I2C addresses ....................................................................................................................... 6

Table 7: GNSS receiver interface specifications ............................................................................................. 8

Table 8: I/O interface specifications ............................................................................................................. 9

Table 9: MTi 1-series module generations .................................................................................................. 17

List of Figures

Figure 1: External components single supply (I2C interface) ........................................................................... 2

Figure 2: Pin configuration of the MTi 1-series module (top view) .................................................................. 4

Figure 3: External components (I2C interface) ............................................................................................... 6

Figure 4: Connections (SPI interface) ........................................................................................................... 7

Figure 5: Connections (UART interface full-duplex) ....................................................................................... 7

Figure 6: Connections (GNSS interface) ........................................................................................................ 8

Figure 7: Layout example .......................................................................................................................... 10

Figure 8: Default sensor fixed coordinate system for the MTi 1-series module .............................................. 10

Figure 9: Location origin of measurements ................................................................................................. 11

Figure 10: High mechanical stress in diagonal crossover between anchor points ........................................... 12

Figure 11: Reducing anchor points to reduce overall stress in the PCB .......................................................... 12

Figure 12: Keeping the MTi 1-series module away from high mechanical stress areas .................................... 12

Figure 13: Recommended MTi 1-series module footprint ............................................................................ 14

Figure 14: MTi 1-series v1.1 dimensions and sensor locations ...................................................................... 17

Figure 15: MTi 1-series v2.0 dimensions and sensor locations ...................................................................... 17

Figure 16: Location PCB number on MTi 1-series module (bottom view) ...................................................... 17

Figure 17: Reflow classification profile (not to scale) ................................................................................... 18

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Hardware Integration Manual MTi 1-series

1 General information

This document provides hardware design instructions for the MTi 1-series module. The MTi 1-series
module is a fully functional, self-contained module that is easy to design-in with limited external hardware
components to be added. The MTi 1-series module can be connected to a host through I2C, SPI or
UART interfaces.

Section 2 shows recommendations for power supplies for the 1-series. Section 3 provides information
about the different communication protocols that can be used, and section 4 describes some general
layout considerations. The last two sections provide information about packaging and handling.

The following symbols are used in this document to highlight important information:

A warning symbol indicates actions that could damage the module.

This document applies to the following products:

Table 1: MTi 1-series latest generation

Product name

Type number

Hardware version1

PCB number2

MTi-1

MTi-1T/R

≥ 2.0

≥ SM171223

MTi-2

MTi-2T/R

≥ 2.0

≥ SM171223

MTi-3

MTi-3T/R

≥ 2.0

≥ SM171223

MTi-7

MTi-7T/R

≥ 2.0

≥ SM171223

This document also applies for previous generations, unless noted otherwise.

Table 2: MTi 1-series previous generation

Product name

Type number

Hardware version

PCB number

MTi-1-8A7G6

MTi-1-8A7G6T/R

≤ 1.1

≤ SM141111

MTi-2-8A7G6

MTi-2-8A7G6T/R

≤ 1.1

≤ SM141111

MTi-3-8A7G6

MTi-3-8A7G6T/R

≤ 1.1

≤ SM141111

1

This number can be found on the packaging label (see Sections 5.1 and 5.2).

2

This number can be found on the bottom side of the MTi 1-series module (see Section 5.3).

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2 Power supply

The MTi 1-series module has two supply pins: VDDA and VDDIO. They can be supplied
independently or tied together to adapt various concepts, depending on the intended application. The
different supply voltages are explained in the following subsections.

2.1 Main supply voltage (VDDIO)

The VDDIO pin is the main supply of the MTi 1-series module. This pin is connected to all the digital
IO’s, and powers the processor on the MTi 1-series module. Section 2.4 shows the acceptable range of

VDDIO. For the most power efficient implementation, the VDDIO pin should be connected to a 1.8 V
power supply.

2.2 Analog supply voltage (VDDA)

The VDDA pin of the MTi 1-series module is connected to all the power supply pins of the sensing
elements that are on the MTi 1-series module. There is no low-dropout regulator (LDO) on the
MTi 1-series. Section 2.4 shows the acceptable range of VDDA. To get the best sensor performance, it
is important that the VDDA pin is supplied by a power supply with a maximum ripple of 50 mVpp.

2.3 Single power supply configuration

The MTi 1-series VDDA and VDDIO supply pins can be connected to the same power supply. When the
MTi 1-series is supplied with a single power supply source, it is strongly recommended to decouple the

VDDA and VDDIO supply pins, for example with a resistor, for the best sensor performance (see Figure

1). This way the digital circuitry will not influence the analogue sensing part. Considering the minimum
operating voltage for VDDA, the single supply voltage VDD should be at least 2.2 V, due to the voltage
drop over R1.

Figure 1: External components single supply (I2C interface)

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2.4 Power supply specifications

Table 3 shows the maximum operating voltage ratings of the MTi 1-series. Exposure to any voltage
beyond maximum operating voltage rating condition for extended periods may affect device reliability
and lifetime.

Table 3: Maximum operating voltage ratings

Min

Max

Unit

VDDA

2.16

3.63 V VDDA ripple

50

mVpp

VDDIO

1.8

VDDA + 0.1

V

3

Previous generation version ≤1.1, VDDA max: 3.45V

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3 Interfaces

3.1 Pin Configuration

Figure 2 shows the pin configuration of the MTi 1-series module. Pin 18, 19 and 20 are only used on the
MTi-7, for MTi-1/2/3 these pins need not be connected (DNC).

Figure 2: Pin configuration of the MTi 1-series module (top view)

3.2 Communication to host

The MTi 1-series modules are designed to be used as peripheral devices in embedded systems. The
MTi 1-series modules support inter-integrated circuit (I2C), serial peripheral interface (SPI) and universal

asynchronous receiver/transmitter (UART) protocols for the communication between the MTi 1-series
module and host CPU. The I2C and SPI protocols are well suited for communication between integrated
circuits and on-board peripherals. To select the correct communication interface, PSEL1 and PSEL0
should be configured accordingly (see section 3.2.1). For interface specifications, see Table 4.

Table 4: Host communication interfaces specifications

Interface

Min

Typ

Max

Units

I2C

Host I2C Interface Speed

400

kHz

SPI

Host SPI Interface Speed

2

MHz

Clock Duty Cycle

30

50

70 % UART

Baud Rates

921.6

4000

kbps

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3.2.1 PSEL serial host communication interface selection

The MTi 1-series modules has four modes of peripheral interfacing. Only one mode can be used at a
time and this is determined by the state of peripheral selection pins PSEL0 and PSEL1 at start up. Table
5 specifies how the PSEL lines select the peripheral interface. Note that the module has internal pull-ups
(30 kΩ – 50 kΩ). Not connecting PSEL results in a value of 1, connecting PSEL to GND results in a
value of 0.

Table 5: Serial host interface selection

Interface

PSEL1

PSEL0

I2C 1 1

SPI 1 0

UART half-duplex

0 1 UART full-duplex

0

0

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3.2.2 I2C

I2C is the default interface (when PSEL1 and PSEL0 pins are floating or connected to VDDIO). The I2C
SCL and SDA pins are open drain and therefore they need pull-up resistors to VDDIO (R2 and R3 in
Figure 3; typical value: 2.7 kΩ).

Figure 3: External components (I2C interface)

The MTi 1-series module acts as an I2C Slave. The I2C slave address is determined by the ADD0, ADD1
and ADD2 pins. These pins are pulled-up internally so when left unconnected the address selection
defaults to ADD[0..2] = 111. Table 6 shows a list of all possible I2C addresses.

Table 6: List of I2C addresses

I2C address

ADD2

ADD1

ADD0

0x1D

0 0 0

0x1E

0 0 1

0x28

0 1 0

0x29

0 1 1

0x68

1 0 0

0x69

1 0 1

0x6A

1 1 0

0x6B (default)

1 1 1

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3.2.3 SPI

For the SPI interface, PSEL1 can be left floating or pulled-up to VDDIO and PSEL0 pin needs to be
connected to GND, as shown in Figure 4.

Figure 4: Connections (SPI interface)

3.2.4 UART

For the UART full-duplex interface, PSEL1 and PSEL0 pins needs to be connected to GND, as shown
in Figure 5. The UART full-duplex communications mode can be used without hardware flow control. In
this case the CTS line needs to be tied low (GND) to make the MTi 1-series transmit. For UART
half-duplex interface, PSEL1 needs to be connected to GND and PSEL0 pin must be left floating (see
Table 5).

Figure 5: Connections (UART interface full-duplex)

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3.3 GNSS receiver and barometer interface

The MTi-7 variant of the MTi 1- series module family supports external inputs from a GNSS receiver like
the uBlox MAX-M8. For the GNSS receiver, the UART communication and PPS/TIMEPULSE pins of
the receiver need to be connected to the AUX_TX, AUX_RX and SYNC_PPS pins of the MTi-7 module.
See Figure 6 for schematic details and Table 7 for interface specifications.

Table 7: GNSS receiver interface specifications

Interface

Typ

Max

Units

UART

Baud Rates

115.2

2000

kbps

Besides the GNSS receiver, the MTi-7 also supports an external barometer like the BMP280. For the
barometer, the SPI pins need to be connected to the AUX_nCS, AUX_MOSI, AUX_MISO and
AUX_SCK pins of the MTi-7 module. See Figure 6 for schematic details.

Figure 6: Connections (GNSS interface)

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3.4 I/O pins

The I/O interface specifications are listed in Table 8.

Table 8: I/O interface specifications

I/O interface

Symbol

Min

Max

Unit

Description

SYNC_IN

V

IL

0.3 · VDDIO

V

Input low voltage

V

IH

0.45 · VDDIO + 0.3

V Input high voltage

V

HYS

0.45 · VDDIO + 0.3

V Threshold hysteresis
voltage

nRST

VIL

0.3 · VDDIO

V

Only drive momentarily

RPU

30

50

kΩ

Pull-up resistor

TP

20 µs

Generated reset pulse
duration

3.4.1 Reset

The reset pin is active low. Drive this pin with an open drain output or momentary (tactile) switch to GND.
During normal operation, this pin should be left floating, as this line is also used for internal resets. This
pin has an internal weak pull-up to VDDIO.

Do not connect the reset pin directly to VDDIO!

3.4.2 SYNC_IN

SYNC_IN pin accepts an external trigger, on which the MTi 1-series sends out the latest available data
message. The SYNC_IN pin is 5V tolerant and can be connected directly to an external device. Please
make sure that the MTi 1-series and the external device are connected to or have the same common
GND. Table 8 shows the electrical specifications.

3.5 DNC/RESERVED pins

These pins are reserved for future use.

Do not connect, leave pins floating!

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4 Design

4.1 PCB layout

To prevent current flows that can influence the performance of the MTi 1-series, it is recommended to
remove all copper (planes) underneath the MTi 1-series as shown in Figure 7.

Figure 7: Layout example

4.1.1 Frames of reference used in MTi 1-series

The MTi 1-series module uses a right-handed coordinate system as the basis of the sensor frame.

Figure 8: Default sensor fixed coordinate system for the MTi 1-series module

Z X Y

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4.1.2 Origin of measurements

The accelerometer determines the origin of measurements. Figure 9 shows the location of the
accelerometer of the MTi 1-series.

Figure 9: Location origin of measurements

4.2 Mechanical stress

In general, it is recommended to place the MTi 1-series module in an area on the PCB with minimal
mechanical stress. The following paragraphs show causes of mechanical stress and ways to reduce it.

4.2.1 Pushbutton contacts

Pushbuttons induce mechanical stress when used. Therefore, it is recommended to keep a reasonable
distance between a pushbutton and the MTi 1-series module.

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4.2.2 Anchor points

Anchor points are usually a cause of mechanical torsional stress. The MTi 1-series module should not
be placed near an anchor point. Furthermore, since a plane is uniquely determined by three points, it is
recommended to affix the PCB with no more than three anchor points. More than three anchor points
over define the PCB plane and therefore induce mechanical stress. Figure 10 shows an example of a
PCB with four anchor points that gives a maximum stress in the centre of the diagonal crossover. Avoid
placing the MTi 1-series module in such an area.

Figure 10: High mechanical stress in diagonal crossover between anchor points

The best way to deal with the problem shown in Figure 10 is to remove one of the anchor points as
shown in Figure 11. This will reduce the overall stress in the PCB. If more anchor points are required
(e.g. in case of a large PCB) the MTi 1-series module should be moved to an area with minimal
mechanical stress, as shown in Figure 12.

Figure 11: Reducing anchor points to reduce overall stress in the PCB

Figure 12: Keeping the MTi 1-series module away from high mechanical stress areas

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4.2.3 Vibrations

The MTi 1-series features an industry-leading signal processing pipeline (AttitudeEngineTM) which
rejects vibrations. For best results however, it is recommended that the MTi 1-series is mechanically
isolated from vibrations as much as possible. Especially in applications where vibrations are likely to
occur, the anchor points of the PCB that holds the MTi 1-series module should be dampened. The
required type of dampening varies from application to application.

4.2.4 Heat

Keep the MTi 1-series module away from heat sources. Thermal gradients can cause mechanical stress,
which can affect the sensor performance of the MTi 1-series.

4.2.5 Sockets

For best performance, it is best to solder the module directly onto a PCB by a solder reflow process.
When placed in a socket, the module may be subjected to mechanical stress by the springs in the
socket, which might result in deteriorated performance.

4.3 Magnetometer

The MTi 1-series uses a 3D magnetometer for measuring the geomagnetic field. This part is sensitive
to magnetic disturbances.

4.3.1 Ferromagnetic materials

Ferromagnetic materials can be magnetized and the magnetic behaviour can change during operation.
This behaviour will influence the measurements of the 3D magnetometer of the MTi 1-series.
Therefore, keep these ferromagnetic materials away from the MTi 1-series.

4.3.2 High currents

High current power lines on the PCB will introduce magnetic fields that will influence the measurements
of the 3D magnetometer of the MTi 1-series. Place high current power lines away from the MTi 1-series.
Example: a power line with a current of 100 mA at a distance of 10 mm, will introduce an error of 2 µT.

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4.4 Footprint

The footprint of the MTi 1-series module is similar to a 28-lead Plastic Leaded Chip Carrier package
(JEDEC MO-047). Although it is recommended to solder the MTi 1-series module directly onto a PCB,
it can also be mounted in a compatible PLCC socket (e.g. 8428-21B1-RK of 3M, as used on the MTi 1­series Development Kit). When using a socket, make sure that it supports the maximum dimensions of
the MTi 1-series module as given in Section 5.3 (note the tolerance of ± 0.1 mm).

Figure 13: Recommended MTi 1-series module footprint

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5 Packaging

The MTi 1-series module is shipped in trays with 20 modules or in reels with 250 modules.

5.1 Tray packaging information

Tray Dimensions (mm)

Tray packaging
information

Pin 1

Length
“X”

Width
“Y”

Height
“Z”

Pocket
X-Pitch

Pocket
Y-Pitch

Pocket
X-Y
Array

Qty/Tray

Qty/Box

322.60

135.90

7.62

14.65

16.00

12 x 12

20 units

20 units

Detail “A”
Marking

NOTES:

• All dimensions are in millimeters.

• Pictured tray representative only, actual tray may look different.

• The hardware version number is labeled SPEC REV on the TNR Label.

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5.2 Reel packaging information

Carrier tape (mm)

Reels (mm)

Pin 1

Packing

Ao

Bo

Ko W Po

P1

P2 A N C W3

Orientation
by quadrant

QTY/
Reel

12.6

-

12.8

12.6

-

12.8

2.9

-

3.10

23.70

-

24.30

3.90

-

4.10

15.90

-

16.10

1.90

-

2.10

177.80

55

12.80

-

13.50

23.90

-

27.40

1 & 2

250

NOTES:

• All dimensions are in millimeters, unless otherwise specified.

• The hardware version number is labeled SPEC REV on the TNR Label.

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5.3 Package drawing

All the MTi 1-series module generations have the same board dimensions and footprint, but the
component placement can differ between generations.

Table 9: MTi 1-series module generations

Version 1.1 (PCB no. SM141111)

Version 2.0 (PCB no. SM171223)

Figure 14: MTi 1-series v1.1 dimensions and
sensor locations

Figure 15: MTi 1-series v2.0 dimensions and sensor
locations

 All dimensions are in mm.

 General tolerances are ± 0.1 mm

Figure 16: Location PCB number on MTi 1-series module (bottom view)

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6 Handling

6.1 Reflow specification

The moisture sensitivity level of the MTi 1-series modules corresponds to JEDEC MSL Level 3, see also:

 IPC/JEDEC J-STD-020E “Joint Industry Standard: Moisture/Reflow Sensitivity Classification for

non-hermetic Solid State Surface Mount Devices”

 IPC/JEDEC J-STD-033C “Joint Industry Standard: Handling, Packing, Shipping and Use of

Moisture/Reflow Sensitive Surface Mount Devices”.

The sensor fulfils the lead-free soldering requirements of the above-mentioned IPC/JEDEC
standard, i.e. reflow soldering with a peak temperature up to 260 °C. Recommended Preheat Area (ts)
is 80-100 sec. The minimum height of the solder after reflow shall be at least 50 µm. This is required for
good mechanical decoupling between the MTi 1-series module and the printed circuit board (PCB) it is
mounted on.

The number of times that MEMS components may be reflowed is limited to three times. As the IMU is
already reflowed once by Xsens in order to produce the MTi 1-series module, the MTi 1-series module
may only be reflowed two times when placed on the PCB board. If the MTi 1-series is designed-in a
double-sided PCB, it is recommended to reflow the side with the MTi 1-series in the second run in order
to prevent large offsets.

For automated pick and placement of the MTi 1-series module please be aware that the component
placement on the module can differ between generations, see Table 9.

Figure 17: Reflow classification profile (not to scale)

6.2 Ultrasonic processes

The MTi 1-series is sensitive to ultrasonic waves (e.g. ultrasonic cleaning/welding), which will
damage the MTi-1 series module. Xsens will offer no warranty against damaged MTi 1-series modules

caused by any ultrasonic processes.

Do not expose the MTi 1-series to ultrasonic processes!

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6.3 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.