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Mod.0818 2017-01 Rev.0
LM940
HW Design Guide
1VV0301352 Rev. 15 2020-05-11
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SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE
NOTICE
While reasonable efforts have been made to assure the accuracy of this document, Telit
assumes no liability resulting from any inaccuracies or omissions in this document, or from
use of the information obtained herein. The information in this document has been carefully
checked and is believed to be reliable. However, no responsibility is assumed for
inaccuracies or omissions. Telit reserves the right to make changes to any products
described herein and reserves the right to revise this document and to make changes from
time to time in content hereof with no obligation to notify any person of revisions or changes.
Telit does not assume any liability arising out of the application or use of any product,
software, or circuit described herein; neither does it convey license under its patent rights
or the rights of others.
It is possible that this publication may contain references to, or information about Telit
products (machines and programs), programming, or services that are not announced in
your country. Such references or information must not be construed to mean that Telit
intends to announce such Telit products, programming, or services in your country.
COPYRIGHTS
This instruction manual and the Telit products described in this instruction manual may be,
include or describe copyrighted Telit material, such as computer programs stored in
semiconductor memories or other media. Laws in the Italy and other countries preserve for
Telit and its licensors certain exclusive rights for copyrighted material, including the
exclusive right to copy, reproduce in any form, distribute and make derivative works of the
copyrighted material. Accordingly, any copyrighted material of Telit and its licensors
contained herein or in the Telit products described in this instruction manual may not be
copied, reproduced, distributed, merged or modified in any manner without the express
written permission of Telit. Furthermore, the purchase of Telit products shall not be deemed
to grant either directly or by implication, estoppel, or otherwise, any license under the
copyrights, patents or patent applications of Telit, as arises by operation of law in the sale
of a product.
COMPUTER SOFTWARE COPYRIGHTS
The Telit and 3rd Party supplied Software (SW) products described in this instruction
manual may include copyrighted Telit and other 3rd Party supplied computer programs
stored in semiconductor memories or other media. Laws in the Italy and other countries
preserve for Telit and other 3rd Party supplied SW certain exclusive rights for copyrighted
computer programs, including the exclusive right to copy or reproduce in any form the
copyrighted computer program. Accordingly, any copyrighted Telit or other 3rd Party
supplied SW computer programs contained in the Telit products described in this instruction
manual may not be copied (reverse engineered) or reproduced in any manner without the
express written permission of Telit or the 3rd Party SW supplier. Furthermore, the purchase
of Telit products shall not be deemed to grant either directly or by implication, estoppel, or
otherwise, any license under the copyrights, patents or patent applications of Telit or other
3rd Party supplied SW, except for the normal non-exclusive, royalty free license to use that
arises by operation of law in the sale of a product.
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USAGE AND DISCLOSURE RESTRICTIONS
I. License Agreements
The software described in this document is the property of Telit and its licensors. It is
furnished by express license agreement only and may be used only in accordance with the
terms of such an agreement.
II. Copyrighted Materials
Software and documentation are copyrighted materials. Making unauthorized copies is
prohibited by law. No part of the software or documentation may be reproduced,
transmitted, transcribed, stored in a retrieval system, or translated into any language or
computer language, in any form or by any means, without prior written permission of Telit
III. High Risk Materials
Components, units, or third-party products used in the product described herein are NOT
fault-tolerant and are NOT designed, manufactured, or intended for use as on-line control
equipment in the following hazardous environments requiring fail-safe controls: the
operation of Nuclear Facilities, Aircraft Navigation or Aircraft Communication Systems, Air
Traffic Control, Life Support, or Weapons Systems (High Risk Activities"). Telit and its
supplier(s) specifically disclaim any expressed or implied warranty of fitness for such High
Risk Activities.
IV. Trademarks
TELIT and the Stylized T Logo are registered in Trademark Office. All other product or
service names are the property of their respective owners.
V. Third Party Rights
The software may include Third Party Right software. In this case you agree to comply with
all terms and conditions imposed on you in respect of such separate software. In addition
to Third Party Terms, the disclaimer of warranty and limitation of liability provisions in this
License shall apply to the Third Party Right software.
TELIT HEREBY DISCLAIMS ANY AND ALL WARRANTIES EXPRESS OR IMPLIED
FROM ANY THIRD PARTIES REGARDING ANY SEPARATE FILES, ANY THIRD PARTY
MATERIALS INCLUDED IN THE SOFTWARE, ANY THIRD PARTY MATERIALS FROM
WHICH THE SOFTWARE IS DERIVED (COLLECTIVELY “OTHER CODE”), AND THE
USE OF ANY OR ALL THE OTHER CODE IN CONNECTION WITH THE SOFTWARE,
INCLUDING (WITHOUT LIMITATION) ANY WARRANTIES OF SATISFACTORY
QUALITY OR FITNESS FOR A PARTICULAR PURPOSE.
NO THIRD PARTY LICENSORS OF OTHER CODE SHALL HAVE ANY LIABILITY FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING WITHOUT LIMITATION LOST PROFITS), HOWEVER CAUSED
AND WHETHER MADE UNDER CONTRACT, TORT OR OTHER LEGAL THEORY,
ARISING IN ANY WAY OUT OF THE USE OR DISTRIBUTION OF THE OTHER CODE
OR THE EXERCISE OF ANY RIGHTS GRANTED UNDER EITHER OR BOTH THIS
LICENSE AND THE LEGAL TERMS APPLICABLE TO ANY SEPARATE FILES, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
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Applicability Table
PRODUCTS
LM940 1.0
LM940 2.0
Information –LM940 HW Versions 1.0 and 2.0 only differ in the pinout. Both variants support the very same features and functions.
Please refert to the section 3. PINS ALLOCATION for more details.
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Contents
NOTICE 2
COPYRIGHTS ................................................................................................ 2
COMPUTER SOFTWARE COPYRIGHTS ...................................................... 2
USAGE AND DISCLOSURE RESTRICTIONS ............................................... 3
I. License Agreements ..................................................................... 3
II. Copyrighted Materials ................................................................... 3
III. High Risk Materials ....................................................................... 3
IV. Trademarks .................................................................................. 3
V. Third Party Rights ......................................................................... 3
APPLICABILITY TABLE ................................................................................ 4
CONTENTS .................................................................................................... 5
1. INTRODUCTION .......................................................................... 9
Scope ................................ ........................................................... 9
Audience....................................................................................... 9
Contact Information, Support ........................................................ 9
Text Conventions ........................................................................ 11
Related Documents .................................................................... 12
2. GENERAL PRODUCT DESCRIPTION ...................................... 13
Overview..................................................................................... 13
Product Variants and Frequency Bands ...................................... 13
2.2.1. RF Bands per Regional Variant .................................................. 13
2.2.1.1. Generic Image Frequency Bands and CA Combinations ............ 13
2.2.1.2. AT&T Image Frequency Bands and CA Combinations................ 14
2.2.1.3. Verizon Image Frequency Bands and CA Combinations ............. 14
2.2.1.4. Sprint Image Frequency Bands and CA Combinations ............... 14
Target market ................................ ............................................. 15
Main features .............................................................................. 15
Block Diagram ............................................................................ 16
TX Output Power ........................................................................ 17
RX Sensitivity ............................................................................. 17
GNSS Receiver Specifications .................................................... 18
Mechanical Specifications ........................................................... 19
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2.9.1. Dimensions ................................................................................. 19
2.9.2. Weight ........................................................................................ 19
Environmental Requirements ...................................................... 19
2.10.1. Temperature Range .................................................................... 19
2.10.2. RoHS Compliance ...................................................................... 20
3. PINS ALLOCATION ................................................................... 21
Pin-out ........................................................................................ 21
LM940 Signals That Must Be Connected .................................... 29
Pin Layout ................................................................................... 29
4. POWER SUPPLY ....................................................................... 32
Power Supply Requirements ....................................................... 32
Power Consumption ................................................................... 32
General Design Rules ................................................................. 33
4.3.1. Electrical Design Guidelines ....................................................... 33
4.3.1.1. + 5V Input Source Power Supply – Design Guidelines ................ 33
4.3.2. Thermal Design Guidelines ......................................................... 33
4.3.3. Power Supply PCB layout Guidelines ......................................... 34
RTC ................................................................ ............................ 35
Reference Voltage ...................................................................... 35
Internal LDO for GNSS bias ........................................................ 35
5. ELECTRICAL SPECIFICATIONS .............................................. 36
Absolute Maximum Ratings – Not Operational ............................ 36
Recommended Operating Conditions ......................................... 36
6. DIGITAL SECTION .................................................................... 37
Logic Levels ................................................................................ 37
6.1.1. 1.8V Pins – Absolute Maximum Ratings ..................................... 37
6.1.2. 1.8V Standard GPIOs ................................................................. 37
6.1.3. 1.8V SIM Card Pins .................................................................... 38
6.1.4. 2.85V Pins – Absolute Maximum Ratings ................................... 38
6.1.5. SIM Card Pins @2.85V ............................................................... 38
Power On.................................................................................... 39
6.2.1. Initialization and Activation State ................................................ 39
Power Off.................................................................................... 40
6.3.1. Graceful Shutdown ..................................................................... 40
6.3.1.1. Graceful Shutdown by AT command ........................................... 41
6.3.2. Fast Shutdown ............................................................................ 41
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6.3.2.1. Fast Shutdown by AT command ................................................. 41
6.3.2.2. Fast Shutdown by GPIO ............................................................. 42
6.3.3. Unconditional Shutdown ............................................................. 43
Reset .......................................................................................... 44
6.4.1. Graceful Reset ............................................................................ 45
6.4.2. Unconditional Hardware Reset ................................................... 45
Dying Gasp ................................................................................. 46
Communication ports .................................................................. 46
6.6.1. USB Interface ................................ ............................................. 47
6.6.2. SIM Interface .............................................................................. 49
6.6.2.1. SIM Schematic Example ............................................................. 51
6.6.3. Control Signals ........................................................................... 51
6.6.3.1. W_DISABLE_N........................................................................... 51
6.6.3.2. WAN_LED_N .............................................................................. 51
6.6.4. General Purpose I/O ................................................................... 52
6.6.4.1. Using a GPIO Pin as Input .......................................................... 53
6.6.4.2. Using a GPIO Pin as Output ....................................................... 53
6.6.4.3. Dedicated I/O .............................................................................. 54
6.6.5. I2C – Inter-integrated circuit ........................................................ 54
Using the Temperature Monitor Function .................................... 55
7. RF SECTION .............................................................................. 56
Antenna requirements................................................................. 56
Main Antenna Requirements....................................................... 56
Antenna Diversity Requirements ................................................. 56
GNSS Receiver .......................................................................... 57
7.4.1. GNSS RF Front End Design ....................................................... 57
Antenna connection .................................................................... 58
7.5.1. Antenna Connector ..................................................................... 58
7.5.2. Antenna Cable ............................................................................ 59
7.5.3. Antenna Installation Guidelines ................................................... 59
8. MECHANICAL DESIGN ............................................................. 61
General ....................................................................................... 61
Finishing & Dimensions .............................................................. 61
Drawing ...................................................................................... 61
9. APPLICATION GUIDE ............................................................... 62
Debug of the LM940 Module in Production ................................. 62
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Bypass Capacitor on Power Supplies ......................................... 62
EMC Recommendations ............................................................. 63
10. PACKAGING .............................................................................. 66
Tray ............................................................................................ 66
11. CONFORMITY ASSESSMENT ISSUES .................................... 68
Approvals.................................................................................... 68
Declaration of Conformity ........................................................... 68
FCC certificates .......................................................................... 68
IC certificates .............................................................................. 68
FCC/IC Regulatory notices ......................................................... 68
RED Regulatory notices .............................................................. 71
12. SAFETY RECOMMENDATIONS................................................ 73
READ CAREFULLY .................................................................... 73
13. REFERENCE TABLE OF RF BANDS CHARACTERISTICS ..... 74
14. ACRONYMS ............................................................................... 76
15. DOCUMENT HISTORY .............................................................. 78
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1. INTRODUCTION
Scope
This document introduces the Telit LM940 module and presents possible and
recommended hardware solutions for developing a product based on the LM940 module.
All the features and solutions detailed in this document are applicable to all LM940 variants,
where “LM940” refers to the variants listed in the Applicability Table.
If a specific feature is applicable to a specific product only, it will be clearly marked.
Information – LM940 refers to all modules listed in the Applicability
Table.
This document takes into account all the basic functions of a wireless module; a valid
hardware solution is suggested for each function, and incorrect solutions and common
errors to be avoided are pointed out.
Obviously, this document cannot embrace every hardware solution or every product that
can be designed. Where the suggested hardware configurations need not be considered
mandatory, the information given should be used as a guide and a starting point for properly
developing a product using the Telit LM940 module.
Information – The integration of the WCDMA/HSPA+/LTE LM940
cellular module within a user application must be carried out according
to the design rules described in this manual.
Audience
This document is intended for Telit customers, especially system integrators, about to
implement their applications using the Telit LM940 module.
Contact Information, Support
For general contact, technical support services, technical questions and report
documentation errors contact Telit Technical Support at:
TS-EMEA@telit.com
TS-AMERICAS@telit.com
TS-APAC@telit.com
TS-SRD@telit.com
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Alternatively, use:
http://www.telit.com/en/products/technical-support-center/contact.php
For detailed information about where you can buy the Telit modules or for recommendations
on accessories and components visit:
http://www.telit.com
To register for product news and announcements or for product questions contact Telit’s
Technical Support Center (TTSC).
Our aim is to make this guide as helpful as possible. Keep us informed of your comments
and suggestions for improvements.
Telit appreciates feedback from the users of our information.
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Text Conventions
Danger – This information MUST be followed or catastrophic
equipment failure or bodily injury may occur.
Caution or Warning – Alerts the user to important points about
integrating the module, if these points are not followed, the module and
end user equipment may fail or malfunction.
Tip or Information – Provides advice and suggestions that may be
useful when integrating the module.
All dates are in ISO 8601 format, i.e. YYYY-MM-DD.
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Related Documents
LM940 SW User Guide, 1VV0301343
LM940 AT Commands Reference Guide, 80545ST10791A
Generic EVB HW User Guide, 1VV0301249
LM940 Interface Board HW User Guide, 1VV0301384
SIM Integration Design Guide Application Note Rev10, 80000NT10001A
Antenna Detection Application Note, 80000NT10002A
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2. GENERAL PRODUCT DESCRIPTION
Overview
The aim of this document is to present possible and recommended hardware solutions
useful for developing a product with the Telit LM940 Mini PCIe module.
LM940 is Telit’s platform for Mini PCIe module for applications, such as M2M applications
and industrial IoT device platforms, based on the following technologies:
• LTE / WCDMA networks for data communication
• Designed for industrial grade quality
In its most basic use case, LM940 can be applied as a wireless communication front-end
for mobile products, offering mobile communication features to an external host CPU
through its rich interfaces.
LM940 is available in hardware variants as listed in Applicability Table
The designated RF band sets per each variant are detailed in Section 2.2, Product
Variants and Frequency Bands.
Product Variants and Frequency Bands
The operating frequencies in LTE & WCDMA modes conform to the 3GPP specifications.
2.2.1. RF Bands per Regional Variant
This table summarizes the LM940, showing the supported band sets and the supported
band pairs and triple for carrier aggregation.
RF Bands and Carrier Aggregation
2.2.1.1. Generic Image Frequency Bands and CA Combinations
LTE FDD
LTE TDD
HSPA+
Bands
1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 20, 25, 26, 28, 29,
30, 66
38, 40, 41
1, 2, 4, 5, 8
GNSS
GPS, GLONASS, BeiDou, Galileo
LTE 2DL carrier aggregation combinations
2CA
CA_1A_3A, CA_1A_5A, CA_1A_7A, CA_1A_8A, CA_1A_20A,
CA_1A_28A, CA_3A_3A, CA_3A_5A, CA_3A_7A, CA_3A_8A,
CA_3A_20A, CA_3A_28A, CA_5A_7A, CA_5A_40A, CA_7A_7A,
CA_7A_8A, CA_7A_20A, CA_7A_28A, 28A_40A, CA_40A_40A, 3C,
CA_5B, CA_7B, CA_7C, CA_38C, CA_40C
LTE 3DL carrier aggregation combinations
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CA_1A_3A_5A, CA_1A_3A_8A, CA_1A_3A_20A, CA_1A_3A_28A,
CA_1A_5A_7A, CA_1A_7A_20A, CA_1A_7A_28A, CA_3A_3A_8A,
CA_3A_7A_8A, CA_3A_7A_20A, CA_3A_7A_28A, CA_1A_3C, CA_3A_7B,
CA_3A_7C, CA_3C_5A, CA_3C_7A, CA_3C_20A, CA_5A_40C,
CA_7B_28A, CA_7C_28A, CA_28A_40C, CA_40D
2.2.1.2. AT&T Image Frequency Bands and CA Combinations
LTE FDD
LTE TDD
HSPA+
Bands
2, 4, 5, 12, 29, 30, 66
N/A
2, 5
LTE 2DL carrier aggregation combinations
2CA
CA_2A_4A, CA_2A_5A, CA_2A_12A,2A_29A, CA_2A_30A, CA_2A_66A,
CA_4A_5A, CA_4A_12A, CA_4A_29A, CA_4A_30A, CA_5A_30A,
CA_5A_66A, CA_12A_30A, CA_12A_66A, CA_30A_29A, CA_30A_66A,
CA_66A_29A, CA_2A_2A, CA_4A_4A, CA_66A_66A, CA_2C, CA_5B,
CA_12B, CA_66B, CA_66C
3CA
CA_2A_2A_5A, CA_2A_2A_12A, CA_2A_4A_5A, CA_2A_4A_12A,
CA_2A_5A_30A, CA_2A_5A_66A, CA_2A_12A_30A, CA_2A_12A_66A,
CA_ 2A_29A_30A, CA_4A_4A_5A, CA_4A_4A_12A,
CA_4A_5A_30A,4A_12B, CA_4A_12A_30A, CA_4A_29A_30A,
CA_5A_30A_66A, CA_5A_66A_66A, CA_5A_66C, CA_12A_30A_66A,
CA_12A_66A_66A
2.2.1.3. Verizon Image Frequency Bands and CA Combinations
LTE FDD
LTE TDD
HSPA+
Bands
2, 4, 5, 13, 66
N/A
N/A
2CA
CA_2A_4A, CA_2A_5A, CA_2A_13A, CA_2A_66A, CA_4A_5A,4A_13A,
CA_5A_66A, CA_13A_66A, CA_2A_2A, CA_4A_4A, CA_66A_66A, CA_5B,
CA_66B, CA_66C
3CA
2A_2A_5A, CA_2A_2A_13A, CA_2A_4A_5A, CA_2A_4A_13A,
CA_2A_5A_66A, CA_2A_13A_66A, CA_4A_4A_5A, CA_4A_4A_13A,
CA_5A_66A_66A, CA_13A_66A_66A, CA_66A_66C, CA_2A_66C,
CA_5A_66C, CA_13A_66C
2.2.1.4. Sprint Image Frequency Bands and CA Combinations
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LTE FDD
LTE TDD
HSPA+
Bands
2, 4, 5, 12, 25, 26
41
N/A
2CA
CA_25A_25A, CA_25A_26A, CA_26A_41A, CA_41A_41A, CA_41C
3CA
CA_26A_41C, CA_41A_41C, CA_41D
Refer to Chapter 13 for details information about frequencies and bands.
Target market
LM940 can be used for applications where very high bandwidth, extensive band coverage
and multiple network carriers certifications in a single SKU are required, such as:
• Industrial equipment
• Internet connectivity devices (mobile reuters, access points)
Main features
The LM940 family of industrial grade cellular modules features LTE and multi-RAT module
together with an on-chip powerful application processor and a rich set of interfaces.
The major functions and features are listed below.
Main Features
Function
Features
Module
• Multi-RAT cellular module for data communication
o LTE FDD/TDD Cat11(600/75 Mbps DL/UL)
o WCDMA up to DC HSPA+, Rel.9
• Support for GPS, GLONASS, BeiDou, Galileo
Two USIM
ports – dual
voltage
• Support of two SIM interfaces
• Class B and Class C support
• Clock rates up to 4 MHz
Interfaces
Rich set of interfaces, including:
• USB2.0 / USB3.0 – USB port is typically used for:
o Flashing of firmware and module configuration
o Production testing
o Accessing the Application Processor’s file system
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Function
Features
o AT command access
o High-speed WWAN access to external host
o Diagnostic monitoring and debugging
o Communication between Java application environment and
an external host CPU
o NMEA data to an external host CPU
• Peripheral Ports – GPIOs
Major software
features
• Advanced security features
o Boot integrity of firmware up to customer applications
o Embedded security
• FOTA (optional)
• Telit Unified AT command set
Form factor
Mini PCIe Form factor (50.95x30x2.7mm), accommodating multiple
RF bands
Environment
and quality
requirements
The entire module is designed and qualified by Telit to satisfy
environment and quality requirements for use in applications.
Single supply
module
The module generates all its internal supply voltages.
RTC
Real-time clock is supported.
Operating
temperature
Range -40 °C to +85 °C
(conditions as defined in Section 2.10.1, Temperature Range)
Block Diagram
Below figure shows an overview of the internal architecture of the LM940 module.
LM940 Block Diagram
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It includes the following sub-functions:
• Application processor, Module subsystem and Location processing with their
external interfaces. These three functions are contained in a single SOC.
• RF front end
• Rich IO interfaces. Depending on which LM940 software features are enabled,
some of its interfaces that are exported through multiplexing may be used
internally and thus may not be usable by the application.
• PMIC with the RTC function inside
TX Output Power
Band
Power class
3G WCDMA
Class 3 (0.2W)
LTE All Bands
Class 3 (0.2W)
RX Sensitivity
Below the 3GPP measurement conditions used to define the RX sensitivity:
Technology
3GPP Compliance
4G LTE
Throughput >95% 10MHz Dual Receiver
3G WCDMA
BER <0.1% 12.2 Kbps Dual Receiver
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Product
Band
Typical Rx Sensitivity (dBm) * / **
(LTE BW = 10 MHz)
LM940
LTE FDD B1
LTE FDD B2
LTE FDD B3
LTE FDD B4
LTE FDD B5
LTE FDD B7
LTE FDD B8
LTE FDD B12
LTE FDD B13
LTE FDD B17
LTE FDD B20
LTE FDD B25
LTE FDD B26
LTE FDD B28
LTE FDD B66
LTE TDD B38
LTE TDD B40
LTE TDD B41
-101.5
-101.0
-101.5
-101.0
-102.5
-99.5
-102.5
-102.0
-102.0
-102.0
-102.0
-101.0
-102.0
-102.0
-101.0
-100.0
-100.0
-99.5
LM940
WCDMA FDD B1
WCDMA FDD B2
WCDMA FDD B4
WCDMA FDD B5
WCDMA FDD B8
-108.5
-108.5
-108.5
-109.5
-109.5
* LTE Rx Sensitivity shall be verified by using both (all) antenna ports simultaneously.
** 3.3 Voltage / Room temperature
GNSS Receiver Specifications
GNSS receiver is a Qualcomm Gen 8c device.
Parameters
Range
Notes
GNSS systems
standalone GPS,
GLONASS, BeiDou and
Galileo
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GPS Protocols
NMEA 0183 V3.0
Acquisition sensitivity
(dBm) - Cold-start
-145
• Qualcomm GPS RF
conducted sensitivity is
defined at the measurement
level: the lowest GPS signal
level (S, in dBm) at the
antenna port for which the
device can still detect an inview satellite 50% of the
time.
• Acquisition/tracking
sensitivity performance
figures assume an open sky
with an active-patch GPS
antenna and a 2.5 dB noise
figure.
Tracking sensitivity
(dBm)
-160
Accuracy in open sky
< 2m CEP-50
Open sky, 1Hz tracking
Standalone time to first fix
(TTFF)
(hot/warm/cold)
1s/29s/32s
Total number of SVs
available
~ 55 SVs
Mechanical Specifications
2.9.1. Dimensions
The LM940 module’s overall dimensions are:
• Length: 50.95 mm, +/- 0.15 mm tolerance
• Width: 30.00 mm, +/- 0.15 mm tolerance
• Thickness: 2.70 mm, +/- 0.15 mm tolerance
2.9.2. Weight
The nominal weight of the LM940 module is 9.6 gram.
Environmental Requirements
2.10.1. Temperature Range
Note
Operating
Temperature Range
–20°C ~ +55°C
This range is defined by 3GPP (the global
standard for wireless mobile communication).
Telit guarantees its modules to comply with all
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Note
the 3GPP requirements and to have full
functionality of the module with in this range.
–40°C ~ +85°C
Telit guarantees full functionality within this
range as well. However, there may possibly
be some performance deviations in this
extended range relative to 3GPP
requirements, which means that some RF
parameters may deviate from the 3GPP
specification in the order of a few dB. For
example: receiver sensitivity or maximum
output power may be slightly degraded.
Even so, all the functionalities, such as call
connection, SMS, USB communication,
UART activation etc., will be maintained, and
the effect of such degradations will not lead to
malfunction.
Storage and non-
operating
Temperature Range
–40°C ~ +85°C
2.10.2. RoHS Compliance
As a part of the Telit corporate policy of environmental protection, the LM940 complies
with the RoHS (Restriction of Hazardous Substances) directive of the European Union
(EU directive 2011/65/EU).
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3. PINS ALLOCATION
Pin-out
Information – The only difference between LM940 1.0 and LM940 2.0
is the pin-out.
Pins highlighted in Blue show that these pins are assigned differently
to LM940 1.0 and LM940 2.0.
Otherwise they support same features and functions.
LM940 1.0 Pin-out
Pin
Signal
I/O
Function
Type
Comment
USB HS 2.0 Communication Port
38
USB_D+
I/O
USB 2.0 Data Plus
Analog
36
USB_D-
I/O
USB 2.0 Data Minus
Analog
USB SS 3.0 Communication Port
25
USB_SS_TX_P
O
USB 3.0 super-
speed transmit –
plus
Analog
23
USB_SS_TX_M
O
USB 3.0 super-
speed transmit –
minus
Analog
33
USB_SS_RX_P
I
USB 3.0 super-
speed receive – plus
Analog
31
USB_SS_RX_M
I
USB 3.0 super-
speed receive –
minus
Analog
SIM Card Interface 1
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8
SIMVCC1
O
Supply output for an
external UIM1 card
1.8V /
2.85V
Power
10
SIMIO1
I/O
Data connection with
an external UIM1
card
1.8V /
2.85V
12
SIMCLK1
O
Clock output to an
external UIM1 card
1.8V /
2.85V
14
SIMRST1
O
Reset output to an
external UIM1 card
1.8V /
2.85V
SIM Card Interface 2
13
SIMVCC2
O
Supply output for an
external UIM2 card
1.8 / 2.85V
Power
19
SIMIO2
I/O
Data connection with
an external UIM2
card
1.8 / 2.85V
17
SIMCLK2
O
Clock output to an
external UIM2 card
1.8 / 2.85V
7 SIMRST2
O
Reset output to an
external UIM2 card
1.8 / 2.85V
Digital I/O (GPIOs)
3
GPIO_01
I/O
General purpose I/O
Can be used as
SIMIN1
1.8V
5
GPIO_02
I/O
General purpose I/O
Can be used as
SIMIN2
1.8V
44
GPIO_03
I/O
General purpose I/O
1.8V
46
GPIO_04
I/O
General purpose I/O
1.8V
Internal 1.8V
Pull-up
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45
GPIO_05
I/O
General purpose I/O
1.8V
47
GPIO_06
I/O
General purpose I/O
1.8V
49
GPIO_07
I/O
General purpose I/O
1.8V
51
GPIO_08
I/O
General purpose I/O
1.8V
Control Signal
1
PCIE_WAKE_N
O
PCIe wake-up
1.8V
20
W_DISABLE_N
I
RF disable
Open-drain
Internal
VBATT Pull-up
42
WAN_LED_N
O
LED control
Open-drain
Miscellaneous Functions
11
VREG_L6_1P8
O
Reference Voltage
1.8V
Power
22
SYSTEM_RESET_N
I
Reset Input
1.8V
I2C Interface
30
I2C_SCL
O
I2C Clock
1.8V
32
I2C_SDA
I/O
I2C Data
1.8V
Power Supply
2
VBATT
I
Power supply
Power
24
VBATT
I
Power supply
Power
39
VBATT
I
Power supply
Power
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41
VBATT
I
Power supply
Power
52
VBATT
I
Power supply
Power
GROUND
4
GND
-
Ground
Ground
9 GND
-
Ground
Ground
15
GND
-
Ground
Ground
18
GND
-
Ground
Ground
21
GND
-
Ground
Ground
26
GND
-
Ground
Ground
27
GND
-
Ground
Ground
29
GND
-
Ground
Ground
34
GND
-
Ground
Ground
35
GND
-
Ground
Ground
37
GND
-
Ground
Ground
40
GND
-
Ground
Ground
43
GND
-
Ground
Ground
50
GND
-
Ground
Ground
Reserved
6
Reserved
-
Reserved (NC)
16
Reserved
-
Reserved (NC)
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LM940 2.0 Pin-out
28
Reserved
-
Reserved (NC)
48
Reserved
-
Reserved (NC)
Pin
Signal
I/O
Function
Type
Comment
USB HS 2.0 Communication Port
38
USB_D+
I/O
USB 2.0 Data Plus
Analog
36
USB_D-
I/O
USB 2.0 Data Minus
Analog
USB SS 3.0 Communication Port
25
USB_SS_TX_P
O
USB 3.0 super-
speed transmit –
plus
Analog
23
USB_SS_TX_M
O
USB 3.0 super-
speed transmit –
minus
Analog
33
USB_SS_RX_P
I
USB 3.0 super-
speed receive – plus
Analog
31
USB_SS_RX_M
I
USB 3.0 super-
speed receive –
minus
Analog
SIM Card Interface 1
8
SIMVCC1
O
Supply output for an
external UIM1 card
1.8V /
2.85V
Power
10
SIMIO1
I/O
Data connection with
an external UIM1
card
1.8V /
2.85V
12
SIMCLK1
O
Clock output to an
external UIM1 card
1.8V /
2.85V
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14
SIMRST1
O
Reset output to an
external UIM1 card
1.8V /
2.85V
SIM Card Interface 2
16
SIMVCC2
O
Supply output for an
external UIM2 card
1.8 / 2.85V
Power
19
SIMIO2
I/O
Data connection with
an external UIM2
card
1.8 / 2.85V
17
SIMCLK2
O
Clock output to an
external UIM2 card
1.8 / 2.85V
6
SIMRST2
O
Reset output to an
external UIM2 card
1.8 / 2.85V
Digital I/O (GPIOs)
3
GPIO_01
I/O
General purpose I/O
Can be used as
SIMIN1
1.8V
5 GPIO_02
I/O
General purpose I/O
Can be used as
SIMIN2
1.8V
44
GPIO_03
I/O
General purpose I/O
1.8V
46
GPIO_04
I/O
General purpose I/O
1.8V
Internal 1.8V
Pull-up
45
GPIO_05
I/O
General purpose I/O
1.8V
47
GPIO_06
I/O
General purpose I/O
1.8V
49
GPIO_07
I/O
General purpose I/O
1.8V
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51
GPIO_08
I/O
General purpose I/O
1.8V
Control Signal
1
PCIE_WAKE_N
O
PCIe wake-up
1.8V
20
W_DISABLE_N
I
RF disable
Open-drain
Internal
VBATT Pull-up
42
WAN_LED_N
O
LED control
Open-drain
Miscellaneous Functions
28
VREG_L6_1P8
O
Reference Voltage
1.8V
Power
48
SYSTEM_RESET_N
I
Reset Input
1.8V
I2C Interface
30
I2C_SCL
O
I2C Clock
1.8V
32
I2C_SDA
I/O
I2C Data
1.8V
Power Supply
2
VBATT
I
Power supply
Power
24
VBATT
I
Power supply
Power
39
VBATT
I
Power supply
Power
41
VBATT
I
Power supply
Power
52
VBATT
I
Power supply
Power
GROUND
4
GND
-
Ground
Ground
9
GND
-
Ground
Ground
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Information – If the I2C interface is not used, the signals can be left
floating.
15
GND
-
Ground
Ground
18
GND
-
Ground
Ground
21
GND
-
Ground
Ground
26
GND
-
Ground
Ground
27
GND
-
Ground
Ground
29
GND
-
Ground
Ground
34
GND
-
Ground
Ground
35
GND
-
Ground
Ground
37
GND
-
Ground
Ground
40
GND
-
Ground
Ground
43
GND
-
Ground
Ground
50
GND
-
Ground
Ground
Reserved
7
Reserved
-
Reserved (NC)
11
Reserved
-
Reserved (NC)
13
Reserved
-
Reserved (NC)
22
Reserved
-
Reserved (NC)
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Information – Unless otherwise specified, RESERVED pins must be
left unconnected (Floating).
LM940 Signals That Must Be Connected
Below table specifies the LM940 signals that must be connected for debugging purposes
even if not used by the end application:
Mandatory Signals
Pin
Signal
Notes
2, 24, 39, 41, 52
VBATT
4, 9, 15, 18, 21, 26, 27, 29, 34, 35, 37, 40, 43,
50
GND
38
USB_D+
If not used, connect to a test
point or an USB connector
36
USB_D-
If not used, connect to a test
point or an USB connector
Pin Layout
Information – The only difference between LM940 1.0 and LM940 2.0
is the pin-out.
Pins highlighted in Blue show that these pins are assigned differently
to LM940 1.0 and LM940 2.0.
Otherwise they support same features and functions.
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4. POWER SUPPLY
The power supply circuitry and board layout are very important parts of the full product
design, with critical impact on the overall product performance. Read the following
requirements and guidelines carefully to ensure a good and proper design.
Power Supply Requirements
The LM940 power requirements are as follows:
Power Supply Requirements
Nominal supply voltage
3.3V
Supply voltage range
3.10V – 3.60V
Maximum ripple on module input supply
30 mV
Power Consumption
Below table provides typical current consumption values of LM940 for various operation
modes.
LM940 Current Consumption
Mode
Average [Typ.]
Mode Description
IDLE Mode
IDLE Mode
60.0 mA
No call connection
USB3.0 is connected to a host
Operative Mode (LTE)
LTE (22 dBm)
750 mA
LTE data call (Non-CA BW 5MHz, RB=1)
1250 mA
LTE data call (CA_3A+7A+20A,
20MHz+20MHz+20MHz, Full RB, 256QAM
DL / 64QAM UL, FDD 600Mbps DL /
75Mbps UL)
Operative Mode (WCDMA)
WCDMA Voice
650 mA
WCDMA voice call (Tx = 23 dBm)
WCDMA HSPA
(22 dBm)
650 mA
WCDMA data call (DC-HSDPA up to 42
Mbps, Max Throughput)
* Worst/best case current values depend on network configuration - not under module
control.
** Applied MPR –2dB 16-QAM full RB
*** 3.3 voltage / room temperature
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Information – The electrical design for the power supply must ensure
a peak current output of at least 2A.
I
General Design Rules
The principal guidelines for the Power Supply Design embrace three different design
steps:
• Electrical design
• Thermal design
• PCB layout
4.3.1. Electrical Design Guidelines
The electrical design of the power supply depends strongly on the power source where
this power is drained.
4.3.1.1. + 5V Input Source Power Supply – Design Guidelines
• The desired output for the power supply is 3.3V. So, being the difference between
the input and desired output voltage not large, a linear regulator can be used. A
switching power supply is preferred to reduce power consumption.
• When using a linear regulator, a proper heat sink must be provided to dissipate the
heat generated.
• A bypass low ESR capacitor of adequate capacity must be provided to cut the
current absorption peaks close to the LM940 module. A 100 μF tantalum capacitor
is usually suitable on VBATT.
• Verify the low ESR capacitor on the power supply output (usually a tantalium one)
is rated at least 10V.
• A protection diode must be inserted close to the power input to protect the LM940
module from power polarity inversion.
4.3.2. Thermal Design Guidelines
The thermal design for the power supply heat sink must be done with the following
specifications:
• Average current consumption during RF transmission @PWR level max in LM940
as shown in Section 4.2, Power Consumption table.
Information – The average consumption during transmission depends
on the power level at which the device is requested to transmit via the
network.
Therefore, the average current consumption can vary significantly.
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Information – The thermal design for the power supply must be made
keeping an average consumption at the maximum transmitting level
during LTE/HSPA data transfer sessions.
Considering the very low current in Idle mode, especially if the Power Saving function is
enabled, it can be assumed that - from the thermal point of view - the device absorbs
significant current only during Data sessions.
In LTE/WCDMA/HSPA mode, the LM940 emits RF signals continuously during
transmission. Therefore, special attention must be paid to dissipate the generated heat.
While designing the application board, the designer must make sure that the LM940
module is located on a large ground area of the application board for effective heat
dissipation.
Information – The LM940 must be connected to the ground and metal
chassis of the host board for best RF performance and thermal
dispersion as well as to have module fixed.
• The two holes at the top of the module and the main ground
of the host board must be fastened together.
• The shield cover of the module and the main board of the host
board or the metal chassis of the host device should be
connected with conductive materials.
4.3.3. Power Supply PCB layout Guidelines
As seen in the electrical design guidelines, the power supply must have a low ESR
capacitor connected to the output to snub current peaks and a protection diode on the
input to protect the supply from spikes and polarity inversion. The placement of these
components is crucial for correct circuitry operation. A misplaced component can be
useless or can even decrease the power supply performances.
• The bypass low ESR capacitor must be placed close to the LM940 power input
pins, or if the power supply is of a switching type, it can be placed close to the
inductor to cut the ripple, as long as the PCB trace from the capacitor to LM940 is
wide enough to ensure a low voltage drop connection even during the 2A current
peaks.
• The protection diode must be placed close to the input connector where the power
source is drained.
• The PCB traces from the input connector to the power regulator IC must be wide
enough to ensure that no significant voltage drops occur during the 2A current
peaks.
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• The PCB traces to LM940 and the bypass capacitor must be wide enough to
ensure that no significant voltage drops occur when the 2A current peaks are
absorbed. This is needed for the same above-mentioned reasons. Try to keep
these traces as short as possible.
• The PCB traces connecting the switching output to the inductor and the switching
diode must be kept as short as possible by placing the inductor and the diode very
close to the power switching IC (only for the switching power supply). This is done
to reduce the radiated field (noise) at the switching frequency (usually 100500 kHz).
• Use a good common ground plane.
• Place the power supply on the board in a way to guarantee that the high current
return paths in the ground plane do not overlap any noise sensitive circuitry, such
as the microphone amplifier/buffer or earphone amplifier.
• The power supply input cables must be kept separate from noise sensitive lines,
such as microphone/earphone cables.
RTC
The RTC within the LM940 module does not have a dedicated RTC supply pin. The RTC
block is supplied by the VBATT supply.
If VBATT power is removed, RTC is not maintained so if maintaining an internal RTC is
needed, VBATT must be supplied continuously.
Reference Voltage
1.8V regulated power supply output is provided as the reference voltage to a host board.
This output is active when the module is ON and goes OFF when the module is shut
down.
This table lists the VREG_L6_IP8 signal of LM940.
LM940 Reference Voltage
PIN
Signal
I/O
Function
Type
Comment
11
VREG_L6_1P8
O
Reference Voltage
power
1.8V
Internal LDO for GNSS bias
The LDO for GNSS bias is applied inside the LM940 model.
The voltage supply come from LM940’s LDO to GNSS active antenna.
This table lists the LDO for GNSS bias of LM940.
LM940 Reference Voltage
Symbol
Parameter
Min
Typ
Max
Unit
V
GNSS DC bias
Voltage of Internal LDO for GNSS bias
2.9
3.1
3.3
[V]
I
GNSS DC bias
Current of Internal LDO for GNSS bias
- - 50
[mA]
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5. ELECTRICAL SPECIFICATIONS
Absolute Maximum Ratings – Not Operational
Caution – A deviation from the value ranges listed below may
harm the LM940 module.
Absolute Maximum Ratings – Not Operational
Symbol
Parameter
Min
Max
Unit
VBATT
Battery supply voltage on pin VBATT
-0.5
+4.0
[V]
Recommended Operating Conditions
Recommended Operating Conditions
Symbol
Parameter
Min
Typ
Max
Unit
T
amb
Ambient temperature
-40
+25
+85
[°C]
VBATT
Battery supply voltage on pin VBATT
3.1
3.3
3.6
[V]
I
VBATT +
I
VBATT_PA
Peak current to be used to dimension
decoupling capacitors on pin VBATT
-
80
2500
[mA]
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6. DIGITAL SECTION
Logic Levels
Unless otherwise specified, all the interface circuits of the LM940 are 1.8V CMOS logic.
Only USIM interfaces are capable of dual voltage I/O.
The following tables show the logic level specifications used in the LM940 interface
circuits. The data specified in the tables below is valid throughout all drive strengths and
the entire temperature ranges.
Caution – Do not connect LM940’s digital logic signal directly to
OEM’s digital logic signal with a level higher than 2.3V for 1.8V
CMOS signals.
6.1.1. 1.8V Pins – Absolute Maximum Ratings
Absolute Maximum Ratings – Not Functional
Parameter
Min
Max
Input level on any digital pin when on
--
+2.16V
Input voltage on analog pins when on
--
+2.16 V
6.1.2. 1.8V Standard GPIOs
Operating Range – Interface Levels (1.8V CMOS)
Parameter
Min
Max
Unit
Comment
VIH
Input high level
1.17V
2.1V
[V]
VIL
Input low level
-0.3V
0.63V
[V] VOH
Output high level
1.35V
1.8V
[V]
VOL
Output low level
0V
0.45V
[V]
IIL
Low-level input leakage
current
-1
--
[uA]
No pull-up
IIH
High-level input leakage
current
-- 1 [uA]
No pull-down
IILPU
Low-level input leakage
current
-97.5
-27.5
[uA]
With pull-up
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Parameter
Min
Max
Unit
Comment
IIHPD
High-level input leakage
current
27.5
97.5
[uA]
With pull-down
CI/o
I/O capacitance
-- 5 [pF]
6.1.3. 1.8V SIM Card Pins
Operating Range – SIM Pins Working at 1.8V
Parameter
Min
Max
Unit
Comment
VIH
Input high level
1.26V
2.1V
[V]
VIL
Input low level
-0.3V
0.36V
[V]
VOH
Output high level
1.44V
1.8V
[V]
VOL
Output low level
0V
0.4V
[V]
IIL
Low-level input leakage
current
--
1000
[uA]
No pull-up
IIH
High-level input leakage
current
-20
20
[uA]
No pull-down
6.1.4. 2.85V Pins – Absolute Maximum Ratings
Absolute Maximum Ratings – Not Functional
Parameter
Min
Max
Input level on any digital pin when on
--
+3.42V
Input voltage on analog pins when on
--
+3.42 V
6.1.5. SIM Card Pins @2.85V
Operating Range – For SIM Pins Operating at 2.85V
Parameter
Min
Max
Unit
Comment
VIH
Input high level
1.995V
3.15V
[V]
VIL
Input low level
-0.3V
0.57V
[V]
VOH
Output high level
2.28V
2.85V
[V]
VOL
Output low level
0V
0.4V
[V]
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Parameter
Min
Max
Unit
Comment
IIL
Low-level input leakage
current
--
1000
[uA]
No pull-up
IIH
High-level input leakage
current
-20
20
[uA]
No pull-down
Power On
The LM940 is automatically turning on when the VBATT is supplied.
Information – To turn on the LM940 module, the SYSTEM_RESET_N
pin must not be asserted low.
6.2.1. Initialization and Activation State
After turning on the LM940 module, the LM940 is not instantly activated because the SW
initialization process takes some time to complete.
For this reason, it is recommended not to communicate with the LM940 during the
Initialization phase.
Boot OK(Shutdown Indicator) goes high at the time of AT command is available via USB.
But this does not mean that it works fully.
As soon as the AT command interface is accessible via USB port, Boot OK line transitions
to high but this does not imply that the device is fully operational yet.
One of GPIO pins can be configured as Shutdown indicator by means of AT#SHDNIND
command: in that case, that GPIO will also work as Boot OK line when the module is
booting.
Please refer to AT Commands Reference Guide for additional details.
In general, as shown in below figure, the LM940 becomes fully operational (in the
Activation state) at least 35 seconds after the VBATT is supplied.
LM940 Initialization and Activation
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Information – To verify if the LM940 has powered up properly, please
check through one of two conditions below:
(1) LM940 and the host should be connected via USB. When USB
driver is completely loaded, the module has powered on
without problems and is ready to accept AT commands.
(2) Monitoring Boot OK (Shutdown Indicator). To use Boot OK
(Shutdown Indicator), Boot OK(Shutdown Indicator) function
must be enabled through AT#SHDNIND. (Refer to the AT
User Guide document)
Information – Active low signals are labeled with a name that ends with
“_N”
Information – To avoid a back-powering effect, it is recommended to
avoid having any HIGH logic level signal applied to the digital pins of
the module when it is powered OFF or during an ON/OFF transition.
Power Off
Power off the device can be done in three different ways:
• Graceful Shutdown by USB AT command AT#SHDN
• Fast Shutdown by GPIO triggered or USB AT command AT#FASTSHDN
• Unconditional Shutdown using the SYSTEM_RESET_N
6.3.1. Graceful Shutdown
To shutdown the LM940 module more safely, host can use the graceful shutdown
function.
The graceful shutdown can be triggered by:
AT command via USB
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6.3.1.1. Graceful Shutdown by AT command
To gracefully shutdown the LM940 module,
First, shutdown AT command must be sent via a USB communication.
Once the shutdown command is sent, the LM940 module enters finalization state,
terminates active processes and prepares to turn off safely.
As shown in below figure, when the module is ready to be turned off, it will be indicated
via Shutdown Indicator.
As shown in the diagram below, Shutdown indicator will indicate when the module is
ready to be turned off.
Please refer to the AT User Guide for more detail about AT#SHDN and AT#SHDNIND.
Graceful Shutdown by AT Command
The DTE should monitor the status of Shutdown Indicator to proceed graceful power-off.
Information – VBATT must not be removed before Shutdown
Indicator goes LOW.
Warning – Not following the recommended shut-down procedures
might damage the device and consequently void the warranty.
6.3.2. Fast Shutdown
For a quicker shutdown of the LM940 module, the host can use the fast shutdown
functionFast shutdown can be triggered by:
AT command via USB
GPIO
6.3.2.1. Fast Shutdown by AT command
Once AT#FASTSHDN command is sent through the USB port, the LM960 enters
finalization state, terminates active processes and preparing to safely turn off.
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As shown in the diagram below, when the module is ready to be turned off, it will be
indicated via Shutdown Indicator.
One of GPIO lines can be configured as Shutdown Indicators function by means of AT
commands: please refer to the AT User Guide for more details about AT#FASTSHDN and
AT#SHDNIND.
Fast Shutdown by AT command
The DTE should monitor the status of Shutdown Indicator to proceed fast power-off.
Information – VBATT must not be removed before Shutdown
Indicator goes LOW.
Warning – Not following the recommended shut-down procedures
might damage the device and consequently void the warranty.
6.3.2.2. Fast Shutdown by GPIO
If properly configured, one of GPIO lines can be used as Fast Shutdown Trigger.
Once the Fast Shutdown Trigger senses a HIGH to LOW transition, fast shutdown is
initiated.
Then the LM940 module enters finalization state, terminates active processes and
prepares to turn off safely. As shown in below figure, when the module is ready to be
turned off, it will be indicated via Shutdown Indicator.
Please refer to the AT User Guide for more detail about enable Shutdown Indicator and
Fast Shutdown Trigger.
Fast Shutdown by GPIO
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The DTE should monitor the status of Shutdown Indicator to proceed fast power-off.
Information – VBATT must not be removed before Shutdown
Indicator goes LOW.
Warning – Not following the recommended shut-down procedures
might damage the device and consequently void the warranty.
6.3.3. Unconditional Shutdown
To turn off the LM940, SYSTEM_RESET_N pad must be asserted low more than 1
seconds and then it should be kept low.
When the SYSTEM_RESET_N is asserted low more than 1 second, the LM940 enters
finalization state and after the end of the shutdown process Shutdown Indicator will go to
low.
Usually, it takes the LM940 less than 100 milliseconds from asserting
SYSTEM_RESET_N until reaching a complete shutdown. The DTE should monitor the
status of Shutdown Indicator to observe the actual power-off.
Information – To completely shut down the LM940 module, the
SYSTEM_RESET_N pin must be asserted and kept low.
Otherwise, the LM940 will turn on again after shut down.
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Information – To avoid a back-powering effect, it is recommended to
avoid having any HIGH logic level signal applied to the digital pins of
the module when it is powered OFF or during an ON/OFF transition.
Warning – Not following the recommended shut-down procedures
might damage the device and consequently void the warranty.
Shutdown by SYSTEM_RESET_N Pad
Below figure shows a simple circuit for this action.
Circuit for Shutdown by SYSTEM_RESET_N
Reset
Reset the device can be done in two different ways:
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• Graceful Reset by USB AT command AT#REBOOT
• Unconditional Reset using the SYSTEM_RESET_N
6.4.1. Graceful Reset
To gracefully restart the LM940 module, AT#REBOOT AT command must be sent via a
USB communication.
Graceful Reset by AT#REBOOT
6.4.2. Unconditional Hardware Reset
To unconditionally restart the LM940 module, the SYSTEM_RESET_N pin must be
asserted low more than 1 seconds and then released.
Unconditional Hardware Reset by SYSTEM_RESET_N Pad
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Information – The Unconditional Hardware Reset must be used only
as an emergency exit procedure, and not as a normal power-off
operation.
Information – Do not use any pull-up resistor on the RESET_N line or
any totem pole digital output. Using a pull-up resistor may cause latchup problems on the LM940 power regulator and improper functioning
of the module. The RESET_N line must be connected only in an opencollector configuration.
Dying Gasp
If any major issue occurs within the Host System, the host itself can use the dying gasp
function by notifying the LM940 module.
One of GPIOs can be configured as Dying Gasp Trigger by means of AT commands.
Once the Dying Gasp Trigger receives a HIGH to LOW transition, the dying gasp
procedure is triggered: the LM460 will send the specified SMS and then initiate fast
shutdown.
Dying Gasp by GPIO, Max Power Non-CA , Current :500mA, 3.3V
Usually dying gasp feature is completed less than 1 second after triggered.
This may take longer depending on network conditions.
Communication ports
Below table summarizes all the hardware interfaces of the LM940 module.
LM940 Hardware Interfaces
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6.6.1. USB Interface
The LM940 module includes super-speed USB3.0 with high-speed USB2.0 backward
compatibility. It is compliant with Universal Serial Bus Specification, Revision 3.0 and can
be used for control and data transfers as well as for diagnostic monitoring and firmware
update.
The USB port is typically the main interface between the LM940 module and OEM
hardware.
USB 3.0 needs capacitors on the TX lines in both directions for AC coupling. In order to
interface USB3.0 with an application board of customer, 0.1uF capacitors should be
installed on USB_SS_RX_P/M lines of the LM940. There are already capacitors on
USB_SS_TX_P/M lines inside LM940 module.
The suggested USB interface connection is the following:
Connection for USB Interface
Interface
LM940
USB
Super-speed USB3.0 with high-speed USB2.0
USIM
x2, dual voltage each (1.8V/2.85V)
Control Signals
W_DISABLE_N
GPIO
X8, GPIO
I2C
I2C (optional)
Antenna ports
2 for Cellular, 1 for GNSS
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Information – The USB signal traces must be routed carefully.
Minimize trace lengths, number of vias, and capacitive loading. The
impedance value should be as close as possible to 90 Ohms
differential.
Warning – At power-up, LM940 success to enumerate SS_USB
interface. But if a hot-plug is attempted in case of SS_USB, then
LM940 may fail to enumerate SS_USB.
Below table lists the USB interface signals.
USB Interface Signals
PIN
Signal
I/O
Function
Type
Comment
38
USB_D+
I/O
USB 2.0 Data Plus
Analog
36
USB_D-
I/O
USB 2.0 Data Minus
Analog
33
USB_SS_RX_P
I
USB 3.0 super-speed
receive – plus
Analog
31
USB_SS_RX_M
I
USB 3.0 super-speed
receive – minus
Analog
25
USB_SS_TX_P
O
USB 3.0 super-speed
transmit – plus
Analog
23
USB_SS_TX_M
O
USB 3.0 super-speed
transmit – minus
Analog
Information – Even if USB communication is not used, it is still highly
recommended to place an optional USB connector on the application
board.
At least test points of the USB signals are required since the USB
physical communication is needed in the case of SW update.
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Information – Consider placing a low-capacitance ESD protection
component to protect LM940 against ESD strikes
If an ESD protection should be added, it is suggested to connect it as follows:
ESD Protection for USB2.0
ESD Protection for USB3.0
6.6.2. SIM Interface
The LM940 supports two external SIM interfaces (1.8V or 2.85V).
Information – LM940 HW versions 1.0 and 2.0 have a different SIM2
pinout.
Below table lists the SIM interface signals.
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SIM Interface Signals
PIN
Signal
I/O
Function
Type
Comment
SIM Card Interface 1
8
SIMVCC1
O
Supply output for an
external UIM1 card
1.8V / 2.85V
Power
10
SIMIO1
I/O
Data connection with an
external UIM1 card
1.8V / 2.85V
12
SIMCLK1
O
Clock output to an
external UIM1 card
1.8V / 2.85V
14
SIMRST1
O
Reset output to an
external UIM1 card
1.8V / 2.85V
SIM Card Interface 2 – LM940 1.0
13
SIMVCC2
O
Supply output for an
external UIM2 card
1.8 / 2.85V
Power
19
SIMIO2
I/O
Data connection with an
external UIM2 card
1.8 / 2.85V
17
SIMCLK2
O
Clock output to an
external UIM2 card
1.8 / 2.85V
7
SIMRST2
O
Reset output to an
external UIM2 card
1.8 / 2.85V
SIM Card Interface 2 – LM940 2.0
6
SIMVCC2
O
Supply output for an
external UIM2 card
1.8 / 2.85V
Power
19
SIMIO2
I/O
Data connection with an
external UIM2 card
1.8 / 2.85V
17
SIMCLK2
O
Clock output to an
external UIM2 card
1.8 / 2.85V
16
SIMRST2
O
Reset output to an
external UIM2 card
1.8 / 2.85V
Digital I/O (GPIOs)
3
GPIO_01
I
UIM1 Card Present
Detect
1.8V
GPIO_01 can be
used as SIMIN1
5
GPIO_02
I
UIM2 Card Present
Detect
1.8V
GPIO_02 can be
used as SIMIN2
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6.6.2.1. SIM Schematic Example
The following Figures illustrate in particular how the application interface should be
designed.
SIM Schematics
SIM_CARD
LM940
SIMIO
SIMCLK
SIMRST
SIMVCC
C1
C2
C3
C5
C6
C7
1
2
3
4
5
6
7
8
C1
C2
C3
C4
.
.
.
33pF
(DNI)
33pF
(DNI)
33pF
(DNI)
100nF
.
SIMIN
Information – LM940 contains an internal pull-up resistor on SIMIO. It
is not necessary to install external pull – up resistor.
6.6.3. Control Signals
The LM940 supports the following control signals:
• W_DISABLE_N
Below table lists the control signals of LM940.
Module Control Signal
PIN
Signal
I/O
Function
Type
Comment
20
W_DISABLE_N
I
RF disable (airplane mode)
1.8V
6.6.3.1. W_DISABLE_N
The W_DISABLE_N signal is provided to make the LM940 goes into the airplane mode:
• Enter into the airplane mode: Low
• Normal operating mode: High or Leave the W_DISABLE_N not connected
LM940 contains an internal VBATT(Nominal 3.3V) pull-up resistor on W_DISABLE_N.
6.6.3.2. WAN_LED_N
The WAN_LED_N signal drives the LED output.
The recommended WAN_LED_N connection is the following:
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Recommended WAN_LED_N connection
R1 and VDD determine the brightness of LED and forward current.
When VDD is 3.3V and LED’s forward voltage is 2.0V, it is recommended to use the value
of R1 from 66 ohm to 250 ohm.
But please determine it in considering the specification of the LED to use.
Information – If enable the LED function and connect the LED to the
WAN_LED_N pin, current consumption may be increased.
6.6.4. General Purpose I/O
The general-purpose I/O pins can be configured to act in three different ways:
• Input
• Output
• Dedicate Function (Customer Requirement)
Input pins can only be read and report digital values (high or low) present on the pin at the
read time. Output pins can only be written or queried and set the value of the pin output.
The following GPIOs are always available as a primary function on the LM940.
Below table lists the GPIO signals of LM940.
GPIOs
Pin no.
Signal
I/O
Function
Type
Drive
Strength
3
GPIO_01
I/O
Configurable
GPIO
Pull-Down
1.8V
2-16 mA
5
GPIO_02
I/O
Configurable
GPIO
Pull-Down
1.8V
2-16 mA
44
GPIO_03
I/O
Configurable
GPIO
Pull-Down
1.8V
2-16 mA
46
GPIO_04
I/O
Configurable
GPIO
Pull-Up
1.8V
2-16 mA
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Pin no.
Signal
I/O
Function
Type
Drive
Strength
45
GPIO_05
I/O
Configurable
GPIO
Pull-Down
1.8V
2-16 mA
47
GPIO_06
I/O
Configurable
GPIO
Pull-Down
1.8V
2-16 mA
49
GPIO_07
I/O
Configurable
GPIO
Pull-Down
1.8V
2-16 mA
51
GPIO_08
I/O
Configurable
GPIO
Pull-Down
1.8V
2-16 mA
6.6.4.1. Using a GPIO Pin as Input
GPIO pins, when used as inputs, can be tied to a digital output of another device and
report its status, provided the device interface levels are compatible with the GPIO 1.8V
CMOS levels.
If a digital output of a device is tied to GPIO input, the pin has interface levels different
than 1.8V CMOS. It can be buffered with an open collector transistor with a 47 kΩ pull-up
resistor to 1.8V.
6.6.4.2. Using a GPIO Pin as Output
GPIO pins, when used as outputs, can drive 1.8V CMOS digital devices or compatible
hardware. When set as outputs, the pins have a push-pull output, and therefore the pullup resistor can be omitted.
GPIO Output Pin Equivalent Circuit
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6.6.4.3. Dedicated I/O
In order to use SIMIN functions, host must use GPIO_01/GPIO_02.
Dedicated I/O
Pin
no.
Signal
IO/Level
Dedicated Function
3
GPIO_01
Input/1.8V
Can be used as SIMIN1 function
5
GPIO_02
Input/1.8V
Can be used as SIMIN2 function
Below functions are not dedicated to specific GPIO.
Custormer use one of GPIOs (GPIO_03 to GPIO_08) as these functions by AT command.
• Boot OK
• Shutdown Indicator
• Shutdown Trigger
• Dying Gasp Trigger
Not Dedicated I/O
Pin
no.
Signal
IO/Level
Dedicated Function
44
GPIO_03
I/O, 1.8V
Can be used as specific functions.
46
GPIO_04
I/O, 1.8V
Can be used as specific functions.
45
GPIO_05
I/O, 1.8V
Can be used as specific functions.
47
GPIO_06
I/O, 1.8V
Can be used as specific functions.
49
GPIO_07
I/O, 1.8V
Can be used as specific functions.
51
GPIO_08
I/O, 1.8V
Can be used as specific functions.
6.6.5. I2C – Inter-integrated circuit
The LM940 supports an I2C interface. The table below lists the LM940 I2C signals.
Module I2C Signal
PIN
Signal
I/O
Function
Type
Comment
30
I2C_SCL
O
I2C Clock
CMOS 1.8V
32
I2C_SDA
I/O
I2C Data
CMOS 1.8V
The I2C interface is used for controlling peripherals inside the module (such as codec,
etc.).
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Information – I2C is supported only on from Modem side as SW
emulation of I2C on GPIO lines.
Please contact Telit Customer support if you use it.
Information – If the I2C interface is not used, the signals can be left
floating.
Using the Temperature Monitor Function
The Temperature Monitor permits to monitor the module’s internal temperature and, if
properly set (see the #TEMPSENS command in LM940 AT Commands Reference Guide
), raises a GPIO to High Logic level when the maximum temperature is reached.
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7. RF SECTION
Antenna requirements
The antenna connection is one of the most important aspect in the full product design as it
strongly affects the product overall performance. Hence please read carefully and follow the
requirements and the guidelines for a proper design.
The LM940 is provided with three RF connectors.
The available connectors are:
• Main RF antenna: TX/RX path
• Auxiliary RF antenna: Combined Diversity and GNSS
• GNSS RF antenna: Dedicated GNSS
Main Antenna Requirements
The antenna for the LM940 device must meet the following requirements:
WCDMA / LTE Antenna Requirements
Frequency range
Depending on frequency band(s) supported by the network
operator, the customer shall use the most suitable antenna for
that/those band(s)
The bands supported by the LM940 is provided in Section 2.2,
Product Variants and Frequency Bands.
Impedance
50 Ohm
Input power
> 24 dBm average power in WCDMA & LTE
VSWR absolute max
<= 10:1
VSWR recommended
<= 2:1
Antenna Diversity Requirements
This product includes an input for a second Rx antenna to improve radio sensitivity. The
function is called Antenna Diversity.
Antenna Diversity Requirements
Frequency range
Depending on frequency band(s) supported by the network
operator, the customer shall use the most suitable antenna for
that/those band(s)
The bands supported by the LM940 is provided in Section 2.2,
Product Variants and Frequency Bands.
Impedance
50Ω
VSWR recommended
≤ 2:1
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The second Rx antenna should not be located in the close vicinity of main antenna. In
order to improve Diversity Gain, Isolation and reduce mutual interaction, the two antennas
should be located at the maximum reciprocal distance possible, taking into consideration
the available space into the application. For the same reason, the Rx antenna should also
be cross-polarized with respect to the main antenna.
Isolation between main antenna and Rx antenna must be at least 10 dB in all uplink
frequency bands.
Envelope Correlation Coefficient (ECC) value should be as close as possible to zero, for
best diversity performance. ECC values below 0.5 on all frequency bands are
recommended.
GNSS Receiver
The LM940 integrates a GNSS receiver that could be used in Standalone mode and in AGPS (assisted GPS), according to the different configurations.
LM940 supports an active antenna.
Frequency range
• Wide-band GNSS:
1560–1606 MHz recommended
• Narrow-band GPS:
1575.42 MHz ± 2 MHz minimum
• Narrow-band Galileo:
1575.42 MHz ± 2 MHz minimum
• Narrow-band BeiDou:
1561.098 MHz ± 2 MHz minimum
• Narrow-band GLONASS:
1601.72 MHz ± 4.2 MHz minimum.
Gain
1.5 dBi < Gain < 3 dBi
Impedance
50 Ohm
Amplification
18 dB < Gain < 21 dB
Supply Voltage
3.1 V
Current consumption
20 mA Typical
7.4.1. GNSS RF Front End Design
The LM940 contains an integrated LNA and pre-select SAW filter.
This allows the module to work well with a passive GNSS antenna. If the antenna cannot
be located near the LM940, then an active antenna (that is, an antenna with a low noise
amplifier built in) can be used with an external dedicated power supply circuit.
GNSS receive path uses either the dedicated GNSS connector or the shared AUX
connector.
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NOTE – Please refer to the LM940 AT Commands Reference Guide,
80545ST10791A for detailed information about GNSS operating
modes and GNSS Antenna selection.
Antenna connection
7.5.1. Antenna Connector
The LM940 is equipped with a set of 50 Ω RF U.FL. connectors from Hirose U.FL-R-SMT-
1(10).
The available connectors are:
• Main RF antenna: TX/RX path
• Auxiliary RF antenna: Combined Diversity and GNSS
• GNSS RF antenna: Dedicated GNSS
See the picture on the below for their position on the interface.
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For more information about mating connectors visit the website http://www.hirose-
connectors.com/
7.5.2. Antenna Cable
Connecting cables between the module and the antenna must have 50 Ω impedance.
If the impedance of the module is mismatched, RF performance is reduced significantly.
If the host device is not designed to use the module’s diversity or GNSS antenna,
terminate the interface with a 50Ω load.
Minimize Antenna Cable Requirements
Impedance
50 Ohm
Max cable loss
0.5 dB
Avoid coupling with other signals.
7.5.3. Antenna Installation Guidelines
• Install the antenna in a location with access to the network radio signal.
• The antenna must be installed such that it provides a separation distance of at
least 20 cm from all persons and must not be co-located or operating in
conjunction with any other antenna or transmitter.
• The antenna must not be installed inside metal cases.
• The antenna must be installed according to the antenna manufacturer’s
instructions.
Furthermore, if the device is developed for the US and/or Canada market, it must comply
with the FCC and/or IC approval requirements.
Information
This device is to be used only for mobile and fixed application. The
antenna(s) used for this transmitter must be installed to provide a
separation distance of at least 20 cm from all persons and must not be
co-located or operating in conjunction with any other antenna or
transmitter. End-Users must be provided with transmitter operation
conditions for satisfying RF exposure compliance. OEM integrators
must ensure that the end user has no manual instructions to remove
or install the LM940 module. Antennas used for this OEM module must
not exceed gain of below table for mobile and fixed operating
configurations.
In the event that these conditions cannot be met (for example certain
laptop configurations or co-location with another transmitter), then the
FCC/IC authorization is no longer considered valid and the FCC/IC ID
cannot be used on the final product. In these circumstances, the OEM
integrator will be responsible for re-evaluating the end product
(including the transmitter) and obtaining a separate FCC/IC
authorization.
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Manual Information to the End User
The OEM integrator has to be aware not to provide information to the
end user regarding how to install or remove this RF module in the
user’s manual of the end product which integrates this module. The
end user manual shall include all required regulatory
information/warning as show in this manual.
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8. MECHANICAL DESIGN
General
The LM940 module was designed to be compliant with a standard lead-free SMT process.
Moreover, it is compatible with the Mini PCIe card 52-pin card edge-type connector.
Finishing & Dimensions
Drawing
This figure shows the mechanical dimensions of the LM940 module.
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9. APPLICATION GUIDE
Debug of the LM940 Module in Production
To test and debug the mounting of the LM940 module, we strongly recommend to add
several test points on the host PCB for the following purposes:
• Checking the connection between the LM940 itself and the application
• Testing the performance of the module by connecting it with an external computer
Depending on the customer application, these test pins include, but are not limited to the
following signals:
• SYSTEM_RESET_N, W_DISABLE_N
• VBATT, GND
• VREG_L6_1P8
• USB_D-, USB_D+
• USB_SS_TX_M, USB_SS_TX_P, USB_SS_RX_M, USB_SS_RX_P
In addition, the following signals are also recommended (but not mandatory):
• GPIO_01, GPIO_02, GPIO_03, GPIO_04, GPIO_05, GPIO_06, GPIO_07,
GPIO_08
Bypass Capacitor on Power Supplies
When a sudden voltage step is asserted to or a cut from the power supplies, the steep
transition causes some reactions such as overshoot and undershoot. This abrupt voltage
transition can affect the device causing it to not operate or to malfunction.
Bypass capacitors are needed to alleviate this behavior. The behavior can appear
differently depending on the various applications. Customers must pay special attention to
this issue when they design their application board.
The length and width of the power lines must be considered carefully, and the capacitance
of the capacitors must be selected accordingly.
The capacitor will also prevent ripple of the power supplies and the switching noise
caused in TDMA systems such as GSM.
Especially, a suitable bypass capacitor must be mounted on the following lines on the
application board:
• VBATT
Recommended values are:
• 100uF for VBATT
Please note that capacitance mainly depends on the conditions of their application board.
Generally, additional capacitance is required when the power line is longer.
And if customers use the fast power down function, then more bypass capacitors should be
mounted on the application board.
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EMC Recommendations
EMC protection on the pins in the table below should be designed by application side
according to the customer’s requirement.
EMC Recommendations
Pin
Signal
I/O
Function
Type
Comment
USB HS 2.0 Communication Port
38
USB_D+
I/O
USB 2.0 Data Plus
Analog
36
USB_D-
I/O
USB 2.0 Data Minus
Analog
USB SS 3.0 Communication Port
33
USB_SS_RX_P
I
USB 3.0 super-
speed receive – plus
Analog
31
USB_SS_RX_M
I
USB 3.0 super-
speed receive –
minus
Analog
25
USB_SS_TX_P
O
USB 3.0 super-
speed transmit –
plus
Analog
23
USB_SS_TX_M
O
USB 3.0 super-
speed transmit –
minus
Analog
SIM Card Interface 1
14
SIMRST1
O
Reset output to an
external UIM1 card
1.8 / 2.85V
12
SIMCLK1
O
Clock output to an
external UIM1 card
1.8 / 2.85V
10
SIMIO1
I/O
Data connection with
an external UIM1
card
1.8 / 2.85V
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8
SIMVCC1
O
Supply output for an
external UIM1 card
1.8 / 2.85V
Power
SIM Card Interface 2
*
See
note
SIMRST2
O
Reset output to an
external UIM2 card
1.8 / 2.85V
17
SIMCLK2
O
Clock output to an
external UIM2 card
1.8 / 2.85V
19
SIMIO2
I/O
Data connection with
an external UIM2
card
1.8 / 2.85V
*
See
note
SIMVCC2
O
Supply output for an
external UIM2 card
1.8 / 2.85V
Power
Digital I/O (GPIOs)
3
GPIO_01
I/O
General purpose I/O
1.8V
5
GPIO_02
I/O
General purpose I/O
1.8V
44
GPIO_03
I/O
General purpose I/O
1.8V
46
GPIO_04
I/O
General purpose I/O
1.8V
45
GPIO_05
I/O
General purpose I/O
1.8V
47
GPIO_06
I/O
General purpose I/O
1.8V
49
GPIO_07
I/O
General purpose I/O
1.8V
51
GPIO_08
I/O
General purpose I/O
1.8V
Power ON/OFF Reset IN/OUT
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* SIMRST2, SIMVCC2, SYSTEM_RESET_N, VREG_L6_1P8 are assigned differently to
LM940 1.0 and 2.0. Please refer to the section 3 PINS ALLOCATION for more details.
All other pins have the following characteristics:
Human Body Model (HBM): ± 1000 V
Charged Device Model (CDM) JESD22-C101-C: ± 250 V
All Antenna pins up to ± 4 kV
Warning – Do not touch without proper electrostatic protective
equipment. The product must be handled with care, avoiding any
contact with the pins because electrostatic discharge may damage the
product itself.
20
W_DISABLE_N
I
Module & RF
ON/OFF Control
1.8V
Active Low
*
See
note
SYSTEM_RESET_N
I
Reset Input
1.8V
Active Low
1.8V Voltage Regulator
*
See
note
VREG_L6_1P8
O
LDO out for 1.8V
Power
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10. PACKAGING
Tray
The LM940 modules are packaged on trays of 20 pieces each. These trays can be used
in SMT processes for pick & place handling.
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11. CONFORMITY ASSESSMENT ISSUES
Approvals
Fully type approved confirming with RE Directive (Directive 2014/53/EU)
CE, GCF
FCC, IC, PTCRB
RoHS and REACH
Approvals for major Mobile Network Operators
Declaration of Conformity
The DoC is available here: www.telit.com/RED/
FCC certificates
The FCC Certifcate is available here: www.fcc.gov/oet/ea/fccid
IC certificates
The IC Certifcate is available here:
https://sms-sgs.ic.gc.ca/equipmentSearch/searchRadioEquipments?execution=e1s1&lang=en
FCC/IC Regulatory notices
Modification statement
Telit has not approved any changes or modifications to this device by the user. Any changes
or modifications could void the user’s authority to operate the equipment.
Telit n’approuve aucune modification apportée à l’appareil par l’utilisateur, quelle qu’en soit
la nature. Tout changement ou modification peuvent annuler le droit d’utilisation de
l’appareil par l’utilisateur.
Interference statement
This device complies with Part 15 of the FCC Rules and Industry Canada licence-exempt
RSS standard(s). Operation is subject to the following two conditions: (1) this device may
not cause interference, and (2) this device must accept any interference, including
interference that may cause undesired operation of the device.
Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils
radio exempts de licence. L'exploitation est autorisée aux deux conditions suivantes : (1)
l'appareil ne doit pas produire de brouillage, et (2) l'utilisateur de l'appareil doit accepter tout
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brouillage radioélectrique subi, même si le brouillage est susceptible d'en compromettre le
fonctionnement.
RF exposure
This equipment complies with FCC and ISED radiation exposure limits set forth for an
uncontrolled environment. The antenna should be installed and operated with minimum
distance of 20 cm between the radiator and your body. Antenna gain must be below:
Cet appareil est conforme aux limites d'exposition aux rayonnements de l’ISED pour un
environnement non contrôlé. L'antenne doit être installé de façon à garder une distance
minimale de 20 centimètres entre la source de rayonnements et votre corps. Gain de
l'antenne doit être ci-dessous:
WCDMA / LTE Antenna (except Band 30)
• Brand : HNS (HANKOOK Network Solution)
• Model Number : WE14-LF-07
• Type : Dipole Antenna
LTE Antenna for Band 30
• Brand : SAE HAN ANTENNA CO.,LTD
• Model Number : DH-23T-ANT
• Type : Dipole Antenna
Mode
Band
Antenna Gain (dBi)
LTE
FDD 1900 PCS – B2
FDD 1800 AWS-1 – B4
FDD 850 – B5
FDD 2600 – B7
FDD 700a – B12
FDD 700c – B13
FDD 700b – B17
FDD 1900+ – B25
FDD 850+ – B26
FDD 700d – B29
FDD 2300 WCS – B30
3.5
3.5
3.0
4.0
3.0
3.0
3.0
3.5
3.0
3.0
1.5
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FDD AWS-3 – B66
TDD 2600 – B38
TDD 2500 – B41
3.5
4.0
4.0
WCDMA
1900 PCS – B2
1800 AWS-1 – B4
850 – B5
3.5
3.5
3.0
This transmitter must not be co-located or operating in conjunction with any other antenna
or transmitter.
L'émetteur ne doit pas être colocalisé ni fonctionner conjointement avec à autre antenne
ou autre émetteur.
FCC Class B digital device notice
This equipment has been tested and found to comply with the limits for a Class B digital
device, pursuant to part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This
equipment generates, uses and can radiate radio frequency energy and, if not installed and
used in accordance with the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off and on, the user
is encouraged to try to correct the interference by one or more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.
Labelling Requirements for the Host device
The host device shall be properly labelled to identify the modules within the host device.
The certification label of the module shall be clearly visible at all times when installed in the
host device, otherwise the host device must be labelled to display the FCC ID and ISED of
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the module, preceded by the words "Contains transmitter module", or the word "Contains",
or similar wording expressing the same meaning, as follows:
L'appareil hôte doit être étiqueté comme il faut pour permettre l'identification des modules
qui s'y trouvent. L'étiquette de certification du module donné doit être posée sur l'appareil
hôte à un endroit bien en vue en tout temps. En l'absence d'étiquette, l'appareil hôte doit
porter une étiquette donnant le FCC ID et l’ISED du module, précédé des mots « Contient
un module d'émission », du mot « Contient » ou d'une formulation similaire exprimant le
même sens, comme suit :
LM940
Contains FCC ID: RI7LM940
Contains IC: 5131A-LM940
CAN ICES-3 (B) / NMB-3 (B)
This Class B digital apparatus complies with Canadian ICES-003.
Cet appareil numérique de classe B est conforme à la norme canadienne ICES-003.
RED Regulatory notices
RF Exposure Information (MPE)
This device has been tested and meets applicable limits for Radio Frequency (RF) exposure.
To comply with the RF exposure requirements, this module must be installed in a host
platform that is intended to be operated in a minimum of 20 cm separation distance to the
user.
OEM/Host manufacturer responsibilities
OEM/Host manufacturers are ultimately responsible for the compliance of the Host and
Module. The final product must be reassessed against all the essential requirements of the
RED before it can be placed on the EU market. This includes reassessing the transmitter
module for compliance with the Radio and EMF essential requirements of the RED. This
module must not be incorporated into any other device or system without retesting for
compliance as multi-radio and combined equipment.
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Antenna Specipication
In all cases assessment of the final product must be met against the Essential requirements
of the RE Directive Articles 3.1(a) and (b), safety and EMC respectively, as well as any
relevant Article 3.3 requirements.
1. The following antenna was verified in the conformity testing, and for compliance the
antenna shall not be modified. A separate approval is required for all other operating
configurations, including different antenna configurations.
2. If any other simultaneous transmission radio is installed in the host platform together
with this module, or above restrictions cannot be kept, a separate RF exposure
assessment and CE equipment certification is required.
WCDMA / LTE Antenna
• Brand : HNS (HANKOOK Network Solution)
• Model Number : WE14-LF-07
• Type : Dipole Antenna
Mode
Band
Antenna Gain (dBi)
LTE
FDD 2100 – B1
FDD 1800+ – B3
FDD 2600 – B7
FDD 900 – B8
FDD 800 – B20
FDD 700 APT – B28
TDD 2600 – B38
TDD 2300 – B40
3.5
3.5
4.0
3.0
3.0
3.0
4.0
4.0
WCDMA
2100 – B1
900 – B8
3.5
3.0
Waste Electrical and Electronic Equipment (WEEE)
This symbol means that according to local laws and regulations your product
and/or its battery shall be disposed of separately from household waste. When
this product reaches its end of life, take it to a collection point designated by
local authorities. Proper recycling of your product will protect human health
and the environment.
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12. SAFETY RECOMMENDATIONS
READ CAREFULLY
Be sure the use of this product is allowed in the country and in the environment required.
The use of this product may be dangerous and has to be avoided in the following areas:
Where it can interfere with other electronic devices in environments such as
hospitals, airports, aircrafts, etc.
Where there is risk of explosion such as gasoline stations, oil refineries, etc. It is the
responsibility of the user to enforce the country regulation and the specific
environment regulation.
Do not disassemble the product; any mark of tampering will compromise the warranty
validity. We recommend following the instructions of the hardware user guides for correct
wiring of the product. The product has to be supplied with a stabilized voltage source and
the wiring has to be conformed to the security and fire prevention regulations. The product
has to be handled with care, avoiding any contact with the pins because electrostatic
discharges may damage the product itself. Same cautions have to be taken for the SIM,
checking carefully the instruction for its use. Do not insert or remove the SIM when the
product is in power saving mode.
The system integrator is responsible for the functioning of the final product; therefore, care
has to be taken to the external components of the module, as well as any project or
installation issue, because the risk of disturbing the LTE & WCDMA network or external
devices or having impact on the security. Should there be any doubt, please refer to the
technical documentation and the regulations in force. Every module has to be equipped with
a proper antenna with specific characteristics. The antenna has to be installed with care in
order to avoid any interference with other electronic devices and has to guarantee a
minimum distance from the body (20 cm). In case this requirement cannot be satisfied, the
system integrator has to assess the final product against the SAR regulation.
The European Community provides some Directives for the electronic equipment
introduced on the market. All of the relevant information is available on the European
Community website:
https://ec.europa.eu/commission/index_en
The text of the Directive 2014/35/EU regarding telecommunication equipment is available,
while the applicable Directives (Low Voltage and EMC) are available at:
http://ec.europa.eu/enterprise/sectors/electrical/
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13. REFERENCE TABLE OF RF BANDS CHARACTERISTICS
RF Bands Characteristics
Mode
Freq. Tx
(MHz)
Freq. Rx
(MHz)
Channels
Tx-Rx
Offset
WCDMA 2100 – B1
1920 ~ 1980
2110 ~ 2170
Tx: 9612 ~ 9888
Rx: 10562 ~ 10838
190 MHz
WCDMA 1900 – B2
1850 ~ 1910
1930 ~ 1990
Tx: 9262 ~ 9538
Rx: 9662 ~ 9938
80 MHz
WCDMA AWS – B4
1710 ~ 1755
2110 ~ 2155
Tx: 1312 ~ 1513
Rx: 1537 ~ 1738
400 MHz
WCDMA 850 – B5
824 ~ 849
869 ~ 894
Tx: 4132 ~ 4233
Rx: 4357 ~ 4458
45 MHz
WCDMA 900 – B8
880 ~ 915
925 ~ 960
Tx: 2712 ~ 2863
Rx: 2937 ~ 3088
45 MHz
LTE 2100 – B1
1920 ~ 1980
2110 ~ 2170
Tx: 18000 ~ 18599
Rx: 0 ~ 599
190 MHz
LTE 1900 – B2
1850 ~ 1910
1930 ~ 1990
Tx: 18600 ~ 19199
Rx: 600 ~ 1199
80 MHz
LTE 1800+ – B3
1710 ~ 1785
1805 ~ 1880
Tx: 19200 ~ 19949
Rx: 1200 ~ 1949
95 MHz
LTE AWS-1 – B4
1710 ~ 1755
2110 ~ 2155
Tx: 19950 ~ 20399
Rx: 1950 ~ 2399
400 MHz
LTE 850 – B5
824 ~ 849
869 ~ 894
Tx: 20400 ~ 20649
Rx: 2400 ~ 2649
45 MHz
LTE 2600 – B7
2500 ~ 2570
2620 ~ 2690
Tx: 20750 ~ 21449
Rx: 2750 ~ 3449
120 MHz
LTE 900 – B8
880 ~ 915
925 ~ 960
Tx: 21450 ~ 21799
Rx: 3450 ~ 3799
45 MHz
LTE 700a – B12
699 ~ 716
729 ~ 746
Tx : 23010 ~ 23179
Rx : 5010 ~ 5179
30 MHz
LTE 700c – B13
777 ~ 787
746 ~ 756
Tx : 23180 ~ 23279
Rx : 5180 ~ 5279
-31 MHz
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Mode
Freq. Tx
(MHz)
Freq. Rx
(MHz)
Channels
Tx-Rx
Offset
LTE 700b – B17
704 ~ 716
734 ~ 746
Tx: 23730 ~ 23849
Rx: 5730 ~ 5849
30 MHz
LTE 800 – B20
832 ~ 862
791 ~ 821
Tx: 24150 ~ 24449
Rx: 6150 ~ 6449
-41 MHz
LTE 1900+ – B25
1850 ~ 1915
1930 ~ 1995
Tx: 26040 ~ 26689
Rx: 8040 ~ 8689
80 MHz
LTE 850+ – B26
814 ~ 849
859 ~ 894
Tx: 26690 ~ 27039
Rx: 8690 ~ 9039
45 MHz
LTE 700 APT – B28
703 ~ 748
758 ~ 803
Tx: 27210 ~ 27659
Rx: 9210 ~ 9659
55 MHz
LTE 700 d – B29
Downlink only
717 ~ 728
Rx: 9660 ~ 9769
–
LTE 2300 WCS – B30
Downlink only
2350 ~ 2360
Rx: 9770 ~ 9869
–
LTE AWS-3 – B66
1710 ~ 1780
2110 ~ 2200
Tx: 131972 ~ 132671
Rx: 66436 ~ 67335
400 MHz
LTE TDD 2600 – B38
2570 ~ 2620
2570 ~ 2620
Tx: 37750 ~ 38249
Rx: 37750 ~ 38249
0 MHz
LTE TDD 2300 – B40
2300 ~ 2400
2300 ~ 2400
Tx: 38650 ~ 39649
Rx: 38650 ~ 39649
0 MHz
LTE TDD 2500 – B41
2496 ~ 2690
2496 ~ 2690
Tx: 39650 ~ 41589
Rx: 39650 ~ 41589
0 MHz
NOTE – The channel numbers that designate carrier frequencies so
close to the operating band edges that the carrier extends beyond the
operating band edge shall not be used. This implies that the first 7, 15,
25, 50, 75 and 100 channel numbers at the lower operating band edge
and the last 6, 14, 24, 49, 74 and 99 channel numbers at the upper
operating band edge shall not be used for channel bandwidths of 1.4,
3, 5, 10, 15 and 20 MHz respectively.
NOTE – For more information on bandwidth support, refer to 3GPP TS
36.521-1 V15.0.0, Table 5.4.2.1-1.
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14. ACRONYMS
TTSC
Telit Technical Support Centre
USB
Universal Serial Bus
HS
High Speed
DTE
Data Terminal Equipment
UMTS
Universal Mobile Telecommunication System
WCDMA
Wideband Code Division Multiple Access
HSDPA
High Speed Downlink Packet Access
HSUPA
High Speed Uplink Packet Access
UART
Universal Asynchronous Receiver Transmitter
HSIC
High Speed Inter Chip
SIM
Subscriber Identification Module
SPI
Serial Peripheral Interface
ADC
Analog – Digital Converter
DAC
Digital – Analog Converter
I/O
Input Output
GPIO
General Purpose Input Output
CMOS
Complementary Metal – Oxide Semiconductor
MOSI
Master Output – Slave Input
MISO
Master Input – Slave Output
CLK
Clock
MRDY
Master Ready
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SRDY
Slave Ready
CS
Chip Select
RTC
Real Time Clock
PCB
Printed Circuit Board
ESR
Equivalent Resistance
VSWR
Voltage Standing Wave Radio
VNA
Vector Network Analyzer
FDD
Frequency division duplex
I2C
Inter-integrated circuit
LTE
Long term evolution
SOC
System-on-Chip
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15. DOCUMENT HISTORY
Revision
Date
Changes
0
2017-01-17
First Draft
1
2017-06-23
Changed document form
2
2017-07-19
Updated 7 RF section
Updated 11.5 RF exposure
3
2017-08-17
Updated 11.1 Approvals
Updated 11.5 RF exposure
Added 11.6 RED Regulatory Notices
Updated 12 Safety Recommendations
4
2017-11-01
Added 2.8 GNSS Receiver Specifications
Updated 2.2.1 RF bands per Regional Variant
Updated 8.3 Drawing
Updated 13 RF bands Characteristics
5
2018-02-22
Updated 13 RF bands Characteristics
Added 6.3 Added Warning
6
2018-04-25
Added 6.5.1 Warning
Deleted Audio Section
Dected WWAN_LED_N, WAKE_N Section
7
2018-12-06
Updated 2 General product description
8
2019-03-15
6 Digital Section
Changed description about setting GPIO as
specific function.
Updated 6.2 Power ON
Updated 6.3 Power Off
Fast Shutdown Trigger: Low Edge Trigger
Updated 6.4 Reset
Added 6.5 Dying Gasp
Dying Gasp Trigger: Low Edge Trigger
Added and updated 6.6.4.2 WAN_LED_N
Added 6.6.5.3 Dedicated I/O
According to the merging LM940 1.0 and LM940
Design guide, following sections are changed.
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Applicability Table, Section 3, Section 6.6.2,
Section 9.3
9
2019-05-28
Deleted some sentence in 2.1 Overview
Deleted some words in 2.4 Main features
Updated 6.3.2 Fast Shutdown Timing
10
2019-05-28
Editorial changes
11
2019-06-14
Moisture Sensitivity Level paragraph added
12
2019-07-18
Band and CA combinations tables updated
13
2020-01-21
Moisture Sensitivity Level corrected
14
2020-02-05
Moisture Sensitivity Level Declaration removed
15
2020-05-11
CA combo table header corrected
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