LM940 HW Design Guide [01.2017] 1VV0301352 Rev. 2 –2017-07-19 Mod.0818 2017-01 Rev.
LM940 HW Design Guide 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.
LM940 HW Design Guide 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.
LM940 HW Design Guide Applicability Table PRODUCTS LM940 1VV0301352 Rev.
LM940 HW Design Guide Contents NOTICE 2 COPYRIGHTS .................................................................................................. 2 COMPUTER SOFTWARE COPYRIGHTS ....................................................... 2 USAGE AND DISCLOSURE RESTRICTIONS ................................................ 3 APPLICABILITY TABLE .................................................................................. 4 CONTENTS ......................................................................
LM940 HW Design Guide 4. POWER SUPPLY ........................................................................ 26 Power Supply Requirements ........................................................ 26 Power Consumption ..................................................................... 26 General Design Rules .................................................................. 27 4.3.1. Electrical Design Guidelines ......................................................... 27 4.3.1.1.
LM940 HW Design Guide Using the Temperature Monitor Function ..................................... 44 7. RF SECTION ................................................................................ 45 Antenna requirements .................................................................. 45 Main Antenna Requirements ........................................................ 45 Antenna Diversity Requirements .................................................. 45 GNSS Receiver ..................................
LM940 HW Design Guide 16. DOCUMENT HISTORY ................................................................ 67 1VV0301352 Rev.
LM940 HW Design Guide 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.
LM940 HW Design Guide 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.
LM940 HW Design Guide 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. 1VV0301352 Rev.
LM940 HW Design Guide 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 1VV0301352 Rev.
LM940 HW Design Guide 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 HW Design Guide Australia B1+B3, B1+B7, B1+B28, B3+B8, B3+B28, B5+B7, B5+B40, B7+B8, B7+B20 LTE 3DL carrier aggregation combinations North America B2+B2+B12/17, B2+B2+B13, B2+B2+B4, B2+B4+B5, B2+B4+B12, B2+B4+B13, B2+B4+B29, B2+B5+B30, B2+B12+B12, B2+B12+B30, B2+B29+B30, B4+B4+B5, B4+B4+B7, B4+B4+B12, B4+B4+B13, B4+B5+B30, B4+B12+B12, B4+B12+B30, B4+B29+B30, B25+B26+B41, B25+B41+B41, B26+B41+B41, B41+B41+B41 Europe B1+B3+B20, B1+B7+B20, B3+B3+B7, B3+B3+B20, B3+B7+B20, B3+B7+B7, B3+B20+B38, B3+B3
LM940 HW Design Guide Function Features Two USIM ports – dual voltage Support for dual SIM Class B and Class C support Clock rates up to 4 MHz Application processor Interfaces Application processor to run customer application code 32 bit ARM Cortex-A7 up to 1.
LM940 HW Design Guide Function Features Environment and quality requirements The entire module is designed and qualified by Telit for satisfying the environment and quality requirements for use in applications1. Single supply module The module generates all its internal supply voltages. RTC The real-time clock is supported. Operating temperature Range -40 °C to +85 °C (conditions as defined in Section 2.9.
LM940 HW Design Guide 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.
LM940 HW Design Guide LM940 LTE FDD B25 -101.0 LTE FDD B26 -102.0 LTE FDD B28 -102.0 LTE FDD B30 -100.5 LTE FDD B66 -101.0 LTE TDD B38 -100.0 LTE TDD B40 -100.0 LTE TDD B41 -99.5 WCDMA FDD B1 -108.5 WCDMA FDD B2 -108.5 WCDMA FDD B4 -108.5 WCDMA FDD B5 -109.5 WCDMA FDD B8 -109.5 * LTE Rx Sensitivity shall be verified by using both (all) antenna ports simultaneously. ** 3.3 Voltage / Room temperature Mechanical specifications 2.8.1.
LM940 HW Design Guide Note –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.
LM940 HW Design Guide 3. PINS ALLOCATION Pin-out LM940 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 superspeed transmit – plus Analog 23 USB_SS_TX_M O USB 3.0 superspeed transmit – minus Analog 33 USB_SS_RX_P I USB 3.0 superspeed receive – plus Analog 31 USB_SS_RX_M I USB 3.
LM940 HW Design Guide SIM Card Interface 2 13 SIMVCC2 O Supply output for an external UIM2 card 1.8 / 2.85V 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 Power Digital I/O (GPIOs) 3 GPIO_01 I/O General purpose I/O, SIMIN1 depending on product 1.8V 5 GPIO_02 I/O General purpose I/O, SIMIN2 depending on product 1.
LM940 HW Design Guide 22 SYSTEM_RESET_N I Reset Input 1.8V Digital Audio Interface 45 DVI _CLK O PCM Clock 1.8V 47 DVI _TX O PCM Data Out 1.8V 49 DVI _RX I PCM Data In 1.8V 51 DVI _WAO O PCM Frame Sync 1.8V 30 I2C_SCL O I2C Clock 1.8V 32 I2C_SDA I/O I2C Data 1.
LM940 HW Design Guide 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 6 Reserved - Reserved (NC) 16 Reserved - Reserved (NC) 28 Reserved - Reserved (NC) 48 Reserved - Reserved (NC) Reserved Information – If the DVI and I2C interface are not used, the signals can
LM940 HW Design Guide Information – Unless otherwise specified, RESERVED pins must be left unconnected (Floating).
LM940 HW Design Guide Pin Layout 1VV0301352 Rev.
LM940 HW Design Guide 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.
LM940 HW Design Guide Information – The electrical design for the power supply must ensure a peak current output of at least 2A. 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.
LM940 HW Design Guide 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 varies significantly.
LM940 HW Design Guide is crucial for the correct operation of the circuitry. 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 drop-less connection even during the 2A current peaks.
LM940 HW Design Guide 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 VGNSS DC bias Voltage of Internal LDO for GNSS bias 2.9 3.1 3.3 [V] IGNSS DC bias Current of Internal LDO for GNSS bias - - 50 [mA] 1VV0301352 Rev.
LM940 HW Design Guide 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 VBATT Parameter Battery supply voltage on pin VBATT Min Max Unit -0.5 +4.
LM940 HW Design Guide 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.
LM940 HW Design Guide Parameter Min Max Unit IIHPD High-level input leakage current 27.5 97.5 [uA] CI/o I/O capacitance -- 5 [pF] 6.1.3. Comment With pull-down 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.
LM940 HW Design Guide 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 W_DISABLE_N pin must not be asserted low. 6.2.1.
LM940 HW Design Guide Information – To check if the LM940 has completely powered on, LM940 and the host must be connected via USB. When USB driver completely loaded, the module has completely powered on and is ready to accept AT commands. Information – During SW initialization of the LM940, the SW configures all pins and interfaces to their desired mode. When VREG_L6_1P8 goes high, this indicates that the initialization of all I/O pins is completed.
LM940 HW Design Guide 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. Shutdown by Software Commnad VPH_PWR Must Be Asserted Low.
LM940 HW Design Guide 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. Communication ports Below table summarizes all the hardware interfaces of the LM940 module. LM940 Hardware Interfaces Interface LM940 USB Super-speed USB3.0 with high-speed USB2.
LM940 HW Design Guide 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. Below table lists the USB interface signals. USB Interface Signals PIN Signal I/O Function Type 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 31 USB_SS_RX_M I 25 USB_SS_TX_P O 23 USB_SS_TX_M O USB 3.
LM940 HW Design Guide Information – Consider placing a low-capacitance ESD protection component to protect LM940 against ESD strikes If an ESD protection should be added, the suggested connectivity is as follows: ESD Protection for USB2.0 ESD Protection for USB3.0 6.5.2. SIM Interface The LM940 supports two external SIM interfaces (1.8V or 2.85V). Below table lists the SIM interface signals. SIM Interface Signals PIN Signal I/O Function Type Comment SIM Card Interface 1 1VV0301352 Rev.
LM940 HW Design Guide 8 SIMVCC1 O Supply output for an external UIM1 card 1.8V / 2.85V 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 Power SIM Card Interface 2 13 SIMVCC2 O Supply output for an external UIM2 card 1.8 / 2.85V 19 SIMIO2 I/O Data connection with an external UIM2 card 1.8 / 2.
LM940 HW Design Guide Information – LM940 contains an internal pull-up resistor on SIMIO. It is not necessary to install external pull – up resistor. 6.5.3. Control Signals The LM940 supports the following control signals: W_DISABLE_N WAKE_N WAN_LED_N Below table lists the control signals of LM940. Module Control Signal PIN Signal I/O 20 1 42 W_DISABLE_N WAKE_N WAN_LED_N I O O 6.5.3.1. Function RF disable (airplane mode) Host wake-up LED control Type Comment 1.8V 1.8V 1.
LM940 HW Design Guide 6.5.3.3. WAN_LED_N The WAN_LED_N signal drives the LED output. The recommended WAN_LED_N connection is the following: Recommended WAN_LED_N connection 6.5.4. 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.
LM940 HW Design Guide 6.5.4.1. 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. 6.5.4.2.
LM940 HW Design Guide Information – I2C is supported only on from Modem side as SW emulation of I2C on GPIO lines. Please contact us 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.
LM940 HW Design Guide 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 read carefully and follow the requirements and the guidelines for a proper design. The LM940 is provided with three RF connectors.
LM940 HW Design Guide 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.
LM940 HW Design Guide 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-SMT1(10).
LM940 HW Design Guide For more information about mating connectors visit the website http://www.hiroseconnectors.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.
LM940 HW Design Guide 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. 1VV0301352 Rev.
LM940 HW Design Guide 8. AUDIO SECTION Audio Interface The LM940 module supports digital audio interfaces. Digital Audio The LM940 module can be connected to an external codec through the digital interface. The product provides a single Digital Audio Interface on the following pins: Digital Audio Interface Signals Pin no. Signal I/O Function Type 51 DVI_WAO O PCM Frame Sync B-PD 1.8V 49 DVI_RX I PCM Data In B-PD 1.8V 47 DVI _TX O PCM Data Out B-PD 1.
LM940 HW Design Guide 9. 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 The LM940 module’s overall dimensions are: Length: 50.95 mm Width: 30.00 mm Thickness: 2.70 mm The module complies with the standard dimensions specified in the PCI Express Mini Card Electromechanical Specification Revision 1.
LM940 HW Design Guide 10.
LM940 HW Design Guide 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 superspeed receive – plus Analog 31 USB_SS_RX_M I USB 3.
LM940 HW Design Guide 8 SIMVCC1 O Supply output for an external UIM1 card 1.8 / 2.85V Power SIM Card Interface 2 7 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 13 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.
LM940 HW Design Guide 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. 1VV0301352 Rev.
LM940 HW Design Guide 11. 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. 1VV0301352 Rev.
LM940 HW Design Guide 1VV0301352 Rev.
LM940 HW Design Guide 12. CONFORMITY ASSESSMENT ISSUES Approvals Fully type approved confirming with R&TTE directive 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.
LM940 HW Design Guide 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.
LM940 HW Design Guide WCDMA FDD 1900+ – B25 3.5 FDD 850+ – B26 3.0 FDD 700 APT – B28 3.0 FDD 700d – B29 3.0 FDD 2300 WCS – B30 1.5 FDD AWS-3 – B66 3.5 TDD 2600 – B38 4.0 TDD 2300 – B40 4.0 TDD 2500 – B41 4.0 2100 – B1 3.5 1900 PCS – B2 3.5 1800 AWS-1 – B4 3.5 850 – B5 3.0 900 – B8 3.0 This transmitter must not be co-located or operating in conjunction with any other antenna or transmitter.
LM940 HW Design Guide 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.
LM940 HW Design Guide 13. 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.
LM940 HW Design Guide 14. REFERENCE TABLE OF RF BANDS CHARACTERISTICS RF Bands Characteristics Mode Freq. Tx (MHz) WCDMA 2100 – B1 1920 ~ 1980 WCDMA 1900 – B2 1850 ~ 1910 WCDMA AWS – B4 1710 ~ 1755 WCDMA 850 – B5 824 ~ 849 Freq.
LM940 HW Design Guide Mode LTE 700b – B17 Freq. Tx (MHz) 704 ~ 716 Freq.
LM940 HW Design Guide 15. ACRONYMS TTSC USB HS DTE UMTS WCDMA HSDPA HSUPA UART HSIC SIM SPI ADC DAC I/O GPIO CMOS MOSI MISO CLK MRDY 1VV0301352 Rev.
LM940 HW Design Guide SRDY CS RTC PCB ESR VSWR VNA FDD I2C LTE SOC 1VV0301352 Rev.
LM940 HW Design Guide 16. 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 12.5 RF exposure 1VV0301352 Rev.
[01.2017] Mod.0818 2017-01 Rev.
