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HE920

Hardware User Guide

1vv0301014 Rev.9 – 2014-01-23

Summary of content (84 pages)

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HE920 Hardware User Guide 1vv0301014 Rev.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 APPLICABILITY TABLE PRODUCT HE920-EU HE920-NA Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 SPECIFICATIONS 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 entirely reliable. However, no responsibility is assumed for inaccuracies or omissions.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 Usage and Disclosure Restrictions 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. Copyrighted Materials Software and documentation are copyrighted materials. Making unauthorized copies is prohibited by law.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 Contents 1. Introduction ................................................. 9 1.1. Scope ..................................................... 9 1.2. Audience .................................................. 9 1.3. Contact Information, Support .............................. 9 1.4. Document Organization .................................... 10 1.5. Text Conventions ......................................... 11 1.6. Related Documents .......
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 5.2.1. Electrical Design Guidelines ............................... 5.2.1.1. + 5V Input Source Power Supply Design Guidelines ........ 5.2.1.2. + 12V Input Source Power Supply Design Guidelines ....... 5.2.1.3. Battery Source Power Supply Design Guidelines ........... 5.2.2. Thermal Design Guidelines .................................. 5.2.3. Power Supply PCB Layout Guidelines ......................... 6. 35 35 36 38 39 40 Antenna(s) ...............
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 11.4.1. Short Description ........................................ 60 11.5. Indication of Network Service Availability ............. 60 11.6. RTC Bypass Out ......................................... 61 11.7. VAUX Power Output ...................................... 61 12. DAC and ADC section ......................................... 62 12.1. DAC Converter .......................................... 62 12.1.1. 12.1.2. 12.1.3. 12.2.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 16.1. 1999/5/EC Directive .................................... 79 16.2. FCC/IC Regulatory notices .............................. 81 17. Safety Recommendations ...................................... 83 18. Document History ............................................ 84 Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 1. Introduction 1.1. Scope The aim of this document is the description of some hardware solutions useful for developing a product with the Telit HE920-EU/NA module. All the features and solutions detailed are applicable to all HE920, whereas “HE920” is intended the modules listed in the applicability table. When a specific feature is applicable to a specific product, it will be clearly highlighted. 1.2.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 1.4. Document Organization This document contains the following chapters: Chapter 1: “Introduction” provides a scope for this document, target audience, contact and support information, and text conventions. Chapter 2: “General Product Description” gives an overview of the features of the product. Chapter 3: “HE920 Module Connections” deals with the pin out configuration and layout.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 1.5. 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.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 2. General Product Description 2.1. Overview The aim of this document is the description of some hardware solutions useful for developing a product with the Telit HE920 module. In this document all the basic functions of a mobile phone will be taken into account; for each one of them a proper hardware solution will be suggested and eventually the wrong solutions and common errors to be avoided will be evidenced.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 2.2. HE920 Mechanical Dimensions The Telit HE920 module overall dimensions are: 2.3. • Length: 34 mm • Width: 40 mm • Thickness: 2.8 mm Weight The module weight of HE920-EU/NA is about 9.0 gram. Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 2.4. Environmental requirements 2.4.1. Temperature range Note Operating Temperature Range Storage and non-operating Temperature Range –20°C ~ +55°C The module is fully functional(*) in all the temperature range, and it fully meets the ETSI specifications. –40°C ~ +85°C The module is fully functional(*) in all the temperature range. Temperatures outside of the range –20°C ÷ +55°C might slightly deviate from ETSI specifications.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 2.5. Operating Frequency The operating frequencies in GSM850, EGSM900, DCS1800, PCS1900, WCDMA modes are conformed to the 3GPP specifications. Mode Freq. TX (MHz) Freq. RX (MHz) Channels TX - RX offset GSM850 824.2 ~ 848.8 869.2 ~ 893.8 128 ~ 251 45 MHz 890.0 ~ 914.8 935.0 ~ 959.8 0 ~ 124 45 MHz 880.2 ~ 889.8 925.2 ~ 934.8 975 ~ 1023 45 MHz DCS1800 1710.2 ~ 1784.8 1805.2 ~ 1879.8 512 ~ 885 95MHz PCS1900 1850.2 ~ 1909.8 1930.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 3. HE920 Module Connections 3.1. PIN-OUT PAD Signal I/O Function USB HS 2.0 Communication Port I/O USB differential Data(+) D19 USB_D+ USB_DI/O USB differential Data(-) F19 Analog input used to sense whether a peripheral device AI is connected, and determine the peripheral type, a host B19 USB_ID(TBD) or a peripheral AI Power sense for the internal USB transceiver A18 USB_VBUS Asynchronous UART – Prog.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 PAD Signal DVI_RX C8 DVI_TX D9 C10 DVI_CLK Digital IO GPIO_01 F9 E10 GPIO_02 GPIO_03 F11 E12 GPIO_04 GPIO_05 F13 E14 GPIO_06 R18 GPIO_07 GPIO_08 S19 U19 GPIO_09 W19 GPIO_10 RF Section AD1 Antenna AU9 ANT_DIV GPS Section ANT_GPS S1 GPS_LNA_EN V2 Miscellaneous Function AP1 RESET* AS1 ON_OFF* I/O Function I/O Digital Voice interface (RX) I/O Digital Voice interface (TX) I/O Digital Voice interface (CLK) Type 1.8V 1.8V 1.
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HE920 Hardware User Guide 1vv0301014 Rev.
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HE920 Hardware User Guide 1vv0301014 Rev.
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HE920 Hardware User Guide 1vv0301014 Rev.
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HE920 Hardware User Guide 1vv0301014 Rev.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 AS1 AP1 D19 F19 A18 AH19 AF19 AA18 AK19 AB19 AD19 ON/OFF* RESET* USB_D+ USB_DUSB_VBUS C103/TXD C104/RXD C105/RTS C106/CTS TXD_AUX RXD_AUX Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 NOTE: The pin defined as RES has to be considered RESERVED and not connected on any pin in the application. The related area on the application has to be kept empty. Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 4. Hardware Commands 4.1. Turning ON the HE920 To turn on HE920, the pad ON_OFF* must be tied low for at least 1 second and then released. The maximum current that can be drained from the ON_OFF* pad is 0.1 mA. A simple circuit to power on the module is illustrated below: 4.2. Initialization and Activation state Upon turning on HE920 module, The HE920 is not activated yet because the boot sequence of HE920 is still going on internally.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 NOTE: To check if the HE920 has powered on, the hardware line PWRMON must be monitored. When PWRMON goes high, the module has powered on. NOTE: Do not use any pull up resistor on the ON_OFF* line, it is internally pulled up. Using pull up resistor may bring to latch up problems on the HE920 power regulator and improper power on/off of the module. The line ON_OFF* must be connected only in open collector configuration.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 4.3. Turning OFF the HE920 Turning off the device can be done in two ways:  by software command (see HE920 Software User Guide)  by Hardware shutdown(pad ON_OFF*) When the device is shut down by software command or by hardware shutdown(pad ON_OFF*), it issues to the network a detach request that informs the network that the device will not be reachable any more.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 4.3.1. Shutdown by Software Command HE920 can be shut down by a software command. When a shut down command is sent, HE920 goes into the finalization state and finally will shut down PWRMON at the end of this state. The period of the finalization state can differ according to the situation in which the HE920 is so it cannot be fixed definitely.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 4.3.2. Hardware Shutdown To turn OFF HE920 the pad ON_OFF* must be tied low for at least 2 seconds and then released. Same circuitry and timing for the power on must be used. When the hold time of ON_OFF* is above 2 seconds, HE920 goes into the finalization state and finally will shut down PWRMON at the end of this state. The period of the finalization state can differ according to the situation in which the HE920 is so it cannot be fixed definitely.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 4.4. Hardware Unconditional Restart (RESET) To unconditionally restart HE920, the pad RESET* must be tied low for at least 200 milliseconds and then released. A simple circuit to do it is: RESET# Unconditional Restart impulse GND NOTE: Do not use any pull up resistor on the RESET* line or any totem pole digital output. Using pull up resistor may bring to latch up problems on the HE920 power regulator and improper functioning of the module.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 For example: 10k 1- Let us assume you need to drive the RESET* pad with a totem pole output of a +1.8/5 V microcontroller (uP_OUT2): +1.8 / 5V 4.5. Hardware Unconditional Shutdown (Power Off) The Unconditional Shutdown of the module could be activated using the SHDN* line (pad AN12). WARNIG: The hardware unconditional Shutdown must not be used during normal operation of the device since it does not detach the device from the network.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 NOTE: Do not use any pull up resistor on the SHDN* line nor any totem pole digital output. Using pull up resistor may bring to latch up problems on the HE920 power regulator and improper functioning of the module. The line SHDN* must be connected only in open collector configuration. The SHDN* is generating an unconditional shutdown(power off) of the module without an automatic restart.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 5. Power Supply The power supply circuitry and board layout are a very important part in the full product design and they strongly reflect on the product overall performances. Read carefully the requirements and the guidelines that will follow for a proper design. 5.1. Power Supply Requirements The HE920 power requirements are: Power Supply Nominal Supply Voltage Max Supply Voltage Supply Voltage Range 3.8V 4.2V 3.4V – 4.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 In GSM/GPRS mode, RF transmission is not continuous and it is packed into bursts at a base frequency of about 216 Hz, and the relative current peaks can be as high as about 2A. Therefore the power supply has to be designed in order to withstand these current peaks without big voltage drops; this means that both the electrical design and the board layout must be designed for this current flow.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 5.2. General Design Rules The principal guidelines for the Power Supply Design embrace three different design steps: 5.2.1.  the electrical design  the thermal design  the PCB layout Electrical Design Guidelines The electrical design of the power supply depends strongly on the power source where this power is drained. We will distinguish them into three categories: 5.2.1.1.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 An example of linear regulator with 5V input is: 5.2.1.2. + 12V Input Source Power Supply Design Guidelines  The desired output for the power supply is 3.8V, hence due to the big difference between the input source and the desired output, a linear regulator is not suited and must not be used. A switching power supply will be preferable because of its better efficiency especially with the 2A peak current load represented by HE920.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 An example of switching regulator with 12V input is in the below schematic (it is split in 2 parts): Switching regulator Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 5.2.1.3. Battery Source Power Supply Design Guidelines  The desired nominal output for the power supply is 3.8V and the maximum allowed voltage is 4.2V, hence a single 3.7V Li-Ion cell battery type is suited for supplying the power to the Telit HE920 module. The three cells Ni/Cd or Ni/MH 3.6 V Nom. battery types or 4V PB types must not be used directly since their maximum voltage can rise over the absolute maximum voltage for HE920 and damage it.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 5.2.2.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 area as large as possible under HE920 which you will mount. You must mount HE920 on the large ground area of your application board and make many ground vias to dissipate the heat. The peak current consumption in the GSM mode is higher than that in WCDMA. However, considering the heat sink is more important in case of WCDMA. As mentioned before, a GSM signal is bursty, thus, the temperature drift is more insensible than WCDMA.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 overlapped to any noise sensitive circuitry as the microphone amplifier/buffer or earphone amplifier.  The power supply input cables must be kept separately from noise sensitive lines such as microphone/earphone cables. Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 6. Antenna(s) The antenna connection and board layout design are the most important parts in the full product design and they strongly reflect on the product’s overall performances. Read carefully and follow the requirements and the guidelines for a proper design. 6.1.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 Furthermore if the device is developed for the US and/or Canada market, it must comply with the FCC and/or IC approval requirements: This device is to be used only for mobile and fixed application.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 6.3. 6.4. GSM/WCDMA Antenna – Installation Guidelines  Install the antenna in a place covered by the GSM/WCDMA signal.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 NOTE: If the RX Diversity is not used/connected, disable the Diversity functionality using the AT#CRXD command and leave the pad AU9 unconnected. Please refer to the AT command User Guide in detail. 6.5. GPS/GNSS Antenna Requirements The use of an active GPS/GNSS antenna is required to achieve better performance. The module is provided with a Digital Output signal to enable the external LNA (pad V2). Parameter Output high level Output low level 6.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 NOTE: The external GNSS LNA and GNSS pre-Filter shall be required for GLONASS application. GNSS LNA requirement shall fulfill the following specifications.  Frequency = 1565 – 1606MHz  Power Gain|S21|2 = 14 – 17dB  NF < 1dB GNSS pre-Filter requirement shall fulfill the following requirements.  Source and Load Impedance = 50Ohm  Insertion Loss (1575.42 – 1576.42MHz) = 1.4dB (Max)  Insertion Loss (1565.42 – 1585.42MHz) = 2.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 An example of GNSS antenna supply circuit is shown in the following image: When using the Telit HE920, since there’s no antenna connector on the module, the antenna must be connected to the HE920 through the PCB with the antenna pad. In the case that the antenna is not directly connected at the antenna pad of the HE920, then a PCB line is required.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23        6.5.5. Keep one layer of the PCB used only for the Ground plane; if possible. Surround (on the sides, over and under) the antenna line on PCB with Ground. Avoid having other signal tracks directly facing the antenna line track. The Ground around the antenna line on PCB has to be strictly connected to the main Ground plane by placing vias once per 2mm at least. Place EM noisy devices as far as possible from HE920 antenna line.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 7. Logic Level Specifications Where not specifically stated, all the interface circuits work at 1.8V CMOS logic levels. The following table shows the logic level specifications used in the Telit HE920 interface circuits: NOTE: Do not connect HE920’s digital logic signal directly to OEM’s digital logic signal of with level higher than 2.7V for 1.8V CMOS signals.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 7.1. Reset Signal(Module Restart) Signal RESET* Function Phone reset (restart) I/O PAD Number I AP1 RESET is used to reset the HE920 module. Whenever this signal is pulled low HE920 is reset (restart). When the device is reset it stops all operations. After the release of the reset HE920 is unconditionally shut down, without doing any detach operations from the network where it is registered.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 8. USB Port The HE920 module includes a Universal Serial Bus (USB) transceiver, which operates at USB low-speed (1.5Mbits/sec), USB full-speed (12Mbits/sec) and USB high-speed (480Mbits/sec). It is compliant with the USB 2.0 specification and can be used for diagnostic monitoring, control and data transfers. The USB_DPLUS and USB_DMINUS signals have a clock rate of 480MHz. The signal traces should be routed carefully.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 9. Serial Ports The serial port on the Telit HE920 is the interface between the module and OEM hardware. 2 serial ports are available on the module:  MODEM SERIAL PORT 1(Main)  MODEM SERIAL PORT 2 (Auxiliary) Several configurations can be designed for the serial port on the OEM hardware. The most common are:  RS232 PC com port;  microcontroller UART @ 1.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 9.1. Modem Serial Port 1 Serial port 1 on the HE920 is a +1.8V UART with all 7 RS232 signals. It differs from the PC-RS232 in the signal polarity (RS232 is reversed) and levels.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 9.2. Modem Serial Port 2 Serial port 2 on the HE920 is a +1.8V UART with only the RX and TX signals. The signals of the HE920 serial port are: PAD Signal I/O Function Type AB19 TXD_AUX O Auxiliary UART (TX Data to DTE) 1.8V Auxiliary UART (RX Data to DTE) 1.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 An example of RS232 level adaption circuitry could be accomplished using a MAXIM transceiver (MAX218). In this case the chipset is capable of translating directly from 1.8V to the RS232 levels (Example on 4 signals only). NOTE: In this case has to be taken in account the length of the lines on the application to avoid problems in case of High-speed rates on RS232.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 10. Audio Section Overview The HE920 module supports an analog audio interface and digital audio interface. 10.1. Analog Audio The HE920 module provides two analog audio paths transmitting and receiving. Please refer to the xE920_Audio_Settings_Application_Note, 80404NT10095A 10.2. Digital Audio HE920 module can be connected to external codec through digital interface.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 11.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 11.1. Logic Level Specifications Where not specifically stated, all the interface circuits work at 1.8V CMOS logic levels. The following table shows the logic level specifications used in the HE920 interface circuits: For 1,8V signals: Absolute Maximum Ratings -Not Functional HE920 Parameter Min Max Input level on any -0.3V +2.7V digital pin when on Input voltage on -0.3V +2.7 V analog pins when on Operating Range - Interface levels (1.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 11.3. Using a GPIO Pad as Output The GPIO pads, when used as outputs, can drive 1.8V CMOS digital devices or compatible hardware. When set as outputs, the pads have a push-pull output and therefore the pull-up resistor may be omitted. Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 11.4. Using the Temperature Monitor Function 11.4.1. Short Description The Temperature Monitor is a function of the module that permits to control its internal temperature and if properly set (see the #TEMPMON command on AT Interface guide) it raises to High Logic level a GPIO when the maximum temperature is reached. 11.5.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 11.6. RTC Bypass Out The VRTC pin brings out the Real Time Clock supply, which is separate from the rest of the digital part, allowing having only RTC going on when all the other parts of the device are off. To this power output a backup capacitor can be added in order to increase the RTC autonomy during power off of the battery. NOTE: NO devices must be powered from this pin. 11.7.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 12. DAC and ADC section 12.1. DAC Converter 12.1.1. Description The HE920 module provides a Digital to Analog Converter. The signal (named DAC_OUT) is available on pad E14 of the HE920 module. The on board DAC is in the range from 0 to 1023. However, an external low-pass filter is necessary. Voltage range (filtered) Range Min 0 0 Max 1.8 1023 Units Volt Steps The precision is 1023 steps, so if we consider that the maximum voltage is 1.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 12.1.3. Low Pass Filter Example . 12.2. ADC Converter 12.2.1. Description The on board ADCs are 8-bit converters. They are able to read a voltage level in the range of 0-2 volts applied on the ADC pin input and store and convert it into 8 bit word. Input Voltage range AD conversion Resolution Min 0 - Max 2.0 8 < 8.6 Units Volt bits mV The HE920 module provides 2 Analog to Digital Converters. 12.2.2.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 13. Mounting the module on your board 13.1. General The HE920 modules have been designed in order to be compliant with a standard lead-free SMT process. Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 13.2. Module Finishing & Dimensions Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 13.3. Recommended foot print for the application 198 pads Top View In order to easily rework the HE920 it is suggested to consider on the application having a 1.5 mm placement inhibit area around the module. It is also suggested, as a common rule for an SMT component, to avoid having a mechanical part of the application in direct contact with the module.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 13.4. Stencil Stencil’s apertures layout can be the same as the recommended footprint (1:1), we suggest a thickness of stencil foil ≥ 120 µm. 13.5. PCB Pad Design Non solder mask defined (NSMD) type is recommended for the solder pads on the PCB. Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 13.6. Recommendations for PCB Pad Dimensions (mm) The recommendation for the PCB pads dimensions are described in the following image (dimensions in mm) Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 It is not recommended to place via or micro-via not covered by solder resist in an area of 0,3 mm around the pads unless it carries the same signal of the pad itself (see following figure). Holes in pad are allowed only for blind holes and not for through holes. Recommendations for PCB Pad Surfaces: Finish Electro-less Ni / Immersion Au Layer thickness (um) 3 –7 / 0.05 – 0.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 13.7. Solder Paste Solder Paste Lead free Sn/Ag/Cu We recommend using only “no clean” solder paste in order to avoid the cleaning of the modules after assembly. 13.7.1. Solder Reflow Recommended solder reflow profile: Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 14. Application guide 14.1. Debug of the HE920 in production To test and debug the mounting of HE920, we strongly recommend foreseeing test pads on the host PCB, in order to check the connection between the HE920 itself and the application and to test the performance of the module connecting it with an external computer.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 14.2. Bypass capacitor on Power supplies When a sudden voltage is asserted to or cut from the power supplies, The steep transition makes some reactions such as the overshoot and undershoot. This abrupt voltage transition can affect the device not to work or make it malfunction. The bypass capacitors are needed to alleviate this behavior and it can be affected differently according to the various applications.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 14.3. SIM interface This section deals with the recommended schematics for the design of SIM interfaces on the application boards. 14.3.1. SIM schematic example Figure 1 illustrates in particular how the application side should be designed, and what values the components should have. NOTE FOR R1: The resistor value on SIMIO pulled up to SIMVCC should be defined accordingly in order to be compliant to 3GPP specification.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 14.4. EMC recommendations HE920 signals are provided by some EMC protections. In any case the accepted levels are different on the pins.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 14.5. Download and Debug Port One of the following options should be chosen in the design of host system in order to download or upgrade the Telit’s software and debug HE920 when HE920 is already mounted on a host system. Users who use both of UART and USB interfaces to communicate HE920 - Must implement a download method in a host system for upgrading HE920 when it’s mounted.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 15. Packing system The Telit HE920 is packaged on trays. Each tray contains 20 pieces with the following dimensions: 15.1. Tray Drawing (1VV0700623_DTS) WARNIG: These trays can withstand a maximum temperature of 65℃. 15.2. Moisture Sensibility The HE920 is a Moisture Sensitive Device level 3, in accordance with standard IPC/JEDEC J-STD-020, take care all the relatives requirements for using this kind of components.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 c) The maximum time between the opening of the sealed bag and the reflow process must be 168 hours if condition b) “IPC/JEDEC J-STD-033A paragraph 5.2” is respected d) Baking is required if conditions b) or c) are not respected e) Baking is required if the humidity indicator inside the bag indicates 10% RH or more Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 16. Conformity Assessment Issues 16.1. 1999/5/EC Directive The HE920-EU module has been assessed in order to satisfy the essential requirements of the R&TTE Directive 1999/05/EC (Radio Equipment & Telecommunications Terminal Equipments) to demonstrate the conformity against the harmonized standards with the final involvement of a Notified Body.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 Final product integrating this module must be assessed against essential requirements of the 1999/5/EC (R&TTE) Directive. It should be noted that assessment does not necessarily lead to testing. Telit Communications S.p.A. recommends carrying out the following assessments: RF spectrum use (R&TTE art. 3.2) EMC (R&TTE art. 3.1b) Health & Safety (R&TTE art. 3.1a) It will depend on the antenna used on the final product.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 16.2. 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.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 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.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 17. Safety Recommendations READ CAREFULLY Be sure about that the use of this product is allowed in your 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.
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HE920 Hardware User Guide 1vv0301014 Rev.9 – 2014-01-23 18. Document History Revision 0 1 Date 2012-02-02 2012-06-04 2 2012-10-24 3 2012-11-14 4 2013-01-02 5 2013-03-21 6 2013-05-14 7 2013-11-08 8 9 2013-11-13 2014-01-23 Changes First issue Renumbered chapters Updated 2.3 Weight Updated 3 HE920 Module Connections Updated 5.1 Power Supply Requirements Updated 6.5 GPS/GNSS Antenna Requirements Updated 9.2 Modem Serial Port 2 Updated 13.2 ADC Converter Updated 14.