Sierra Wireless AR7552 Cellular/PCS WCDMA/LTE Modem User Manual Hardware Integration Guide

Sierra Wireless Inc. Cellular/PCS WCDMA/LTE Modem Hardware Integration Guide

AirPrime - AR7552 - Hardware Integration Guide - Rev1.0_v7

4117336 Rev 1.0 May 18, 2015 AirPrime AR7552 Hardware Integration Guide
4117336 Rev 1.0 May 18, 2015 2 Hardware Integration Guide Important Notice Due to the nature of wireless communications, transmission and reception of data can never be guaranteed. Data may be delayed, corrupted (i.e., have errors) or be totally lost. Although significant delays or losses of data are rare when wireless devices such as the Sierra Wireless modem are used in a normal manner with a well-constructed network, the Sierra Wireless modem should not be used in situations where failure to transmit or receive data could result in damage of any kind to the user or any other party, including but not limited to personal injury, death, or loss of property. Sierra Wireless accepts no responsibility for damages of any kind resulting from delays or errors in data transmitted or received using the Sierra Wireless modem, or for failure of the Sierra Wireless modem to transmit or receive such data. Safety and Hazards Do not operate the Sierra Wireless modem in areas where cellular modems are not advised without proper device certifications. These areas include environments where cellular radio can interfere such as explosive atmospheres, medical equipment, or any other equipment which may be susceptible to any form of radio interference. The Sierra Wireless modem can transmit signals that could interfere with this equipment. Do not operate the Sierra Wireless modem in any aircraft, whether the aircraft is on the ground or in flight. In aircraft, the Sierra Wireless modem MUST BE POWERED OFF. When operating, the Sierra Wireless modem can transmit signals that could interfere with various onboard systems. Note: Some airlines may permit the use of cellular phones while the aircraft is on the ground and the door is open. Sierra Wireless modems may be used at this time. The driver or operator of any vehicle should not operate the Sierra Wireless modem while in control of a vehicle. Doing so will detract from the driver or operator’s control and operation of that vehicle. In some states and provinces, operating such communications devices while in control of a vehicle is an offence. Limitations of Liability This manual is provided “as is”. Sierra Wireless makes no warranties of any kind, either expressed or implied, including any implied warranties of merchantability, fitness for a particular purpose, or noninfringement. The recipient of the manual shall endorse all risks arising from its use. The information in this manual is subject to change without notice and does not represent a commitment on the part of Sierra Wireless. SIERRA WIRELESS AND ITS AFFILIATES SPECIFICALLY DISCLAIM LIABILITY FOR ANY AND ALL DIRECT, INDIRECT, SPECIAL, GENERAL, INCIDENTAL, CONSEQUENTIAL, PUNITIVE OR EXEMPLARY DAMAGES INCLUDING, BUT NOT LIMITED TO, LOSS OF PROFITS OR REVENUE OR ANTICIPATED PROFITS OR REVENUE ARISING OUT OF THE USE OR INABILITY TO USE ANY SIERRA WIRELESS PRODUCT, EVEN IF SIERRA WIRELESS AND/OR ITS AFFILIATES HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES OR THEY ARE FORESEEABLE OR FOR CLAIMS BY ANY THIRD PARTY. Notwithstanding the foregoing, in no event shall Sierra Wireless and/or its affiliates aggregate liability arising under or in connection with the Sierra Wireless product, regardless of the number of events, occurrences, or claims giving rise to liability, be in excess of the price paid by the purchaser for the Sierra Wireless product. Customer understands that Sierra Wireless is not providing cellular or GPS (including A-GPS) services. These services are provided by a third party and should be purchased directly by the Customer.
4117336 Rev 1.0 May 18, 2015 3 Hardware Integration Guide SPECIFIC DISCLAIMERS OF LIABILITY: CUSTOMER RECOGNIZES AND ACKNOWLEDGES SIERRA WIRELESS IS NOT RESPONSIBLE FOR AND SHALL NOT BE HELD LIABLE FOR ANY DEFECT OR DEFICIENCY OF ANY KIND OF CELLULAR OR GPS (INCLUDING A-GPS) SERVICES. Patents This product may contain technology developed by or for Sierra Wireless Inc. This product includes technology licensed from QUALCOMM®. This product is manufactured or sold by Sierra Wireless Inc. or its affiliates under one or more patents licensed from InterDigital Group and MMP Portfolio Licensing. Copyright © 2015 Sierra Wireless. All rights reserved. Trademarks Sierra Wireless®, AirPrime®, AirLink®, AirVantage®, WISMO® and the Sierra Wireless and Open AT logos are registered trademarks of Sierra Wireless, Inc. or one of its subsidiaries. Watcher® is a registered trademark of Netgear, Inc., used under license. Windows® and Windows Vista® are registered trademarks of Microsoft Corporation. Macintosh® and Mac OS X® are registered trademarks of Apple Inc., registered in the U.S. and other countries. QUALCOMM® is a registered trademark of QUALCOMM Incorporated. Used under license. Other trademarks are the property of their respective owners. Contact Information Sales Desk: Phone: 1-604-232-1488 Hours: 8:00 AM to 5:00 PM Pacific Time Contact: http://www.sierrawireless.com/sales Post: Sierra Wireless 13811 Wireless Way Richmond, BC Canada V6V 3A4 Technical Support: support@sierrawireless.com RMA Support: repairs@sierrawireless.com Fax: 1-604-231-1109 Web: http://www.sierrawireless.com/ Consult our website for up-to-date product descriptions, documentation, application notes, firmware upgrades, troubleshooting tips, and press releases: www.sierrawireless.com
4117336 Rev 1.0 May 18, 2015 4 Hardware Integration Guide Document History Version Date Updates 1.0 May 18, 2015 Creation based on document 4116922: AirPrime - AR7558 - Hardware Integration Guide - Rev1.0.
4117336 Rev 1.0 May 18, 2015 5 Contents 1. INTRODUCTION .................................................................................................. 7 1.1. General Features ............................................................................................................... 7 2. POWER INTERFACE ........................................................................................... 8 2.1. Power Supply .................................................................................................................... 8 2.2. Absolute Maximum and ESD Ratings ............................................................................... 8 2.3. Power and Ground Recommendations ............................................................................. 9 3. RF SPECIFICATION .......................................................................................... 10 3.1. LTE RF Interface ............................................................................................................. 10 3.1.1. LTE Max TX Output Power ...................................................................................... 10 3.1.2. LTE RX Sensitivity ................................................................................................... 10 3.2. WCDMA RF Interface ...................................................................................................... 11 3.2.1. WCDMA Max TX Output Power ............................................................................... 11 3.2.2. WCDMA RX Sensitivity ............................................................................................ 11 3.3. WWAN Antenna Interface ............................................................................................... 12 3.3.1. WWAN Antenna Recommendations ........................................................................ 12 3.4. Primary Antenna Diagnostics .......................................................................................... 13 3.5. RX2 Antenna Diagnostics ............................................................................................... 13 4. AUDIO ................................................................................................................ 15 4.1. Analog Audio ................................................................................................................... 15 4.2. Digital Audio .................................................................................................................... 16 5. ROUTING CONSTRAINTS AND RECOMMENDATIONS ................................. 17 5.1. RF Routing Recommendations ....................................................................................... 17 5.2. Power and Ground Recommendations ........................................................................... 19 5.3. Antenna Recommendations ............................................................................................ 19 5.4. Interface Circuit Recommendations ................................................................................ 20 6. REGULATORY INFORMATION ......................................................................... 22 6.1. Important Notice .............................................................................................................. 22 6.2. Safety and Hazards ......................................................................................................... 22 6.3. Important Compliance Information for USA OEM Integrators ......................................... 22 7. REFERENCES ................................................................................................... 24 7.1. Reference Documents ..................................................................................................... 24 7.2. Abbreviations ................................................................................................................... 24
4117336 Rev 1.0 May 18, 2015 6 List of Tables Table 1. AirPrime AR7552 Embedded Module ............................................................................... 7 Table 2. Power Supply Requirements ............................................................................................. 8 Table 3. Power Supply Pads ........................................................................................................... 8 Table 4. AirPrime AR7552 Absolute Maximum Ratings .................................................................. 8 Table 5. Conducted TX (Transmit) Max output Power Tolerances – LTE Bands ......................... 10 Table 6. Conducted RX Sensitivity 3GPP (BW: 10MHz) – LTE Bands (Note 1, 4) ...................... 11 Table 7. AirPrime AR7552 Maximum WCDMA Transmitter Output Power .................................. 11 Table 8. AirPrime AR7552 Minimum WCDMA Receiver Sensitivity ............................................. 11 Table 9. AirPrime AR7552 WWAN Antenna Characteristics ........................................................ 12 Table 10. WWAN Antenna Interface Pads ...................................................................................... 12 Table 11. AirPrime AR7552 WWAN Antenna Recommendations ................................................. 12 Table 12. Primary Antenna ADC Characteristics ............................................................................ 13 Table 13. Primary Antenna Diagnostics Ranges ............................................................................ 13 Table 14. RX2 Antenna ADC Characteristics.................................................................................. 13 Table 15. RX2 Antenna Diagnostics Ranges .................................................................................. 14 Table 16. Analog Audio Interface Pads ........................................................................................... 15 Table 17. Analog Audio Interface Characteristics ........................................................................... 15 Table 18. Digital Audio Interface Pads ............................................................................................ 16 Table 19. The specification of RF Trace of The CCB, Main Port .................................................... 21 Table 20. The specification of RF Trace of The CCB, Diversity and GPS Port ............................. 21 Table 21. Reference Specifications ................................................................................................. 24 Table 22. Abbreviations ................................................................................................................... 24
4117336 Rev 1.0 May 18, 2015 7 1. Introduction 1.1. General Features The AirPrime AR7552 embedded modules are designed for the automotive industry. They support LTE, WCDMA air interface standards and shares hardware and firmware interfaces with the AirPrime AR5550 and AR855x. They also have Global Navigation Satellite System (GNSS) capabilities including GPS and GLONASS. The AirPrime AR7552 embedded modules are based on the Qualcomm MDM9615 wireless chipset and support the following bands. Table 1. AirPrime AR7552 Embedded Module Product Description Band Support AirPrime AR7552 LTE/WCDMA embedded module LTE: B2, B4, B5, B7, B17 WCDMA: B2, B5
4117336 Rev 1.0 May 18, 2015 8 2. Power Interface 2.1. Power Supply The AirPrime AR7552 embedded module is powered via a single regulated DC power supply, 3.7V nominal. The power supply requirements can be found in the following table. Table 2. Power Supply Requirements Power Supply Min Typ Max Units Main DC Power Input Range 3.4 3.7 4.2 V Power Supply Ripple 0 to 1kHz - - 200 mVpp >1kHz - - 50 mVpp Maximum Current draw AR7552 - - tbd mA AirPrime AR7552 does not support USB bus-powered operation. DC power must be supplied via the VBATT input. Table 3. Power Supply Pads Pad Name Direction Function If Unused EA2 VBATT Input Power Supply Input Must Be Used EB2 VBATT Input Power Supply Input Must Be Used EC2 VBATT Input Power Supply Input Must Be Used 2.2. Absolute Maximum and ESD Ratings This section defines the Absolute Maximum and Electrostatic Discharge (ESD) Ratings of the AirPrime AR7552 embedded modules. Warning: If these parameters are exceeded, even momentarily, damage may occur to the device. Table 4. AirPrime AR7552 Absolute Maximum Ratings Parameter Min Max Units VBATT Power Supply Input - 5.0 V VIN Voltage on any digital input or output pin - VCC_1v8+0.5 V IIN Latch-up current -100 100 mA Maximum Voltage applied to antenna interface pins VANT Primary Antenna - 36 V RX2 Antenna - 36 V GNSS Antenna - 36 V ESD Ratings
4117336 Rev 1.0 May 18, 2015 9 Hardware Integration Guide Power Interface Parameter Min Max Units ESD1 Primary, RX2 and GNSS antenna pads - Contact - ± 8 kV All other signal pads - Contact - ± 1.5 kV 1 The ESD Simulator configured with 330pF, 1000Ω. Caution: The AirPrime AR7552 embedded modules are sensitive to Electrostatic Discharge. ESD countermeasures and handling methods must be used when handling the AirPrime AR7552 devices. 2.3. Power and Ground Recommendations Power and ground routing is critical to achieving optimal performance of the AirPrime AR7552 devices when integrated into an application. Recommendations:  Do not use a separate GND for the Antennas  Connections to GND from the AirPrime AR7552 should be flooded plane using thermal reliefs to ensure reliable solder joints.  VBATT is recommended to be routed as a wide trace(s) directly from the 4V supply to the LGA pad.
4117336 Rev 1.0 May 18, 2015 10 3. RF Specification This section presents the WWAN RF interface of the AirPrime AR7552 series of embedded modules. The specifications for the LTE, CDMA and WCDMA interfaces are defined. 3.1. LTE RF Interface This section presents the LTE RF Specification for the AirPrime AR7552. 3.1.1. LTE Max TX Output Power The Maximum Transmitter Output Power of the AirPrime AR7552 embedded modules are specified in the following table. Table 5. Conducted TX (Transmit) Max output Power Tolerances – LTE Bands Band Standard (dBm) (Note 2) Class A (dBm) (Note 3) Notes B2 23 ±2.7dB 23 ±2.0dB Note 1,4 B4 23 ±2.7dB 23 ±2.0dB Note 1 B5 23 ±2.7dB 23 ±2.0dB Note 1 B7 23 ±2.7dB 22.5 +3.2/-1.7dB Note 1,4 B17 23 ±2.7dB 23 ±2.0dB Note 1 Note 1: The test configurations for all of the entries in the table above are per 3GPP specification, Connectorized (Class 3). Note 2: Per 3GPP TS 36.521-1 6.2.2 UE Maximum Output Power ( No MPR);and for B13,Per VzW's Supplementary_RF_Conformance. 2.1 Maximum Output Power – No MPR Or A-MPR Note 3: Class A is defined in 3.3 Environmental Note 4: For transmission bandwidths (Figure 5.4.2-1) confined within FUL_low and FUL_low + 4 MHz or FUL_high – 4 MHz and FUL_high, the maximum output power requirement is relaxed by reducing the lower tolerance limit by 1.5 dB. 3.1.2. LTE RX Sensitivity The Minimum Receiver Sensitivity of the AirPrime AR7552 embedded modules are specified in the following table. Note: For the table below: Dual receiver (SIMO) per 3GPP TS 36.521-1 Rx Sensitivity Specification. Sensitivity values scale with bandwidth: x_MHz_Sensitivity = 10 MHz_Sensitivity - 10*log(10 MHz/x_MHz) 10 MHz BW,and 50 RB DownLink and Up Link as 3GPP TS 36.521-1 Table 7.3.5-2. All values are preliminary pending transceiver matching and testing.
4117336 Rev 1.0 May 18, 2015 11 Hardware Integration Guide RF Specification Table 6. Conducted RX Sensitivity 3GPP (BW: 10MHz) – LTE Bands (Note 1, 4) Band Standard (dBm) (Note 2) Room Typical (dBm) Class A (Extreme) Typical (dBm) (Note 5) Class A Limit ( dBm) (Note 5) B2 -94.3 -101 -100 -95.5 B4 -96.3 -101.5 -101 -97 B5 -94.3 -102.5 -102 -95.5 B7 -94.3 -100 -99 -95.5 B17 -93.3 -102 -101 -94.5 Note 1: Dual receiver (SIMO) Per 3GPP TS 36.521-1 Rx Sensitivity Specification. Note 2: Per 3GPP Specification. Note 3:Sensitivity values scale with bandwidth: x_MHz_Sensitivity = 10 MHz_Sensitivity - 10*log(10 MHz/x_MHz) Note 4: 10 MHz BW,and 50 RB DownLink and Up Link as 3GPP TS 36.521-1 Table 7.3.5-2. Note 5: Class A is defined in 3.3 Environmental Note 6: The requirement is modified by -0.5 dB when the carrier frequency of the assigned E-UTRA channel bandwidth is within 865-894 MHz. 3.2. WCDMA RF Interface This section presents the WCDMA RF Specification for the AirPrime AirPrime AR7552 embedded modules. 3.2.1. WCDMA Max TX Output Power The Maximum Transmitter Output Power of the AirPrime AR7552 embedded module are specified in the following table. Table 7. AirPrime AR7552 Maximum WCDMA Transmitter Output Power Band Frequency Band Nominal Max TX Output Power Tolerance II (1900/PCS) 1850 MHz to 1910 MHz +23.5 dBm +2.2/-2.7 dB V (850/CELL) 824 MHz to 849 MHz 3.2.2. WCDMA RX Sensitivity The Minimum Receiver Sensitivity of the AirPrime AR7552 embedded module are specified in the following table. Table 8. AirPrime AR7552 Minimum WCDMA Receiver Sensitivity Band Frequency Band Minimum RX Downlink Criteria II (1900/PCS) 1930 MHz to 1990 MHz -106 dBm (Class A) -105 dBm (Class B) BER < 0.001 V (850/CELL) 869 MHz to 894 MHz -107 dBm (Class A) -106 dBm (Class B)
4117336 Rev 1.0 May 18, 2015 12 Hardware Integration Guide RF Specification 3.3. WWAN Antenna Interface The specification for the WWAN Antenna Interface of the AirPrime AR7552 embedded modules are defined in the table below. Table 9. AirPrime AR7552 WWAN Antenna Characteristics Characteristics WCDMA B5 LTE B5 WCDMA B2 LTE B2 LTE B4 LTE B7 LTE B17 Frequency (MHz) TX 824-849 1850-1910 1710 – 1755 2500-2570 704 – 716 RX 869-894 1930-1990 2110 – 2155 2620-2690 734– 746 Impedance RF 50 Ω VSWR max RX 2:1 TX 2:1 Maximum Voltage Primary Antenna – 36 Volts RX2 Antenna – 36 Volts (LTE MIMO: tbd) Note: RX2 Antenna port is RX only, RX parameters in the above tables are also applicable. Table 10. WWAN Antenna Interface Pads Pad Name Direction Function BA11 GND Primary Antenna Ground BA12 PRIMARY_ANT Input/Output Primary Antenna Interface BA13 GND Primary Antenna Ground BA7 GND Diversity Antenna Ground BA8 DIVERSITY_ANT Input Diversity Antenna Interface BA9 GND Diversity Antenna Ground 3.3.1. WWAN Antenna Recommendations The table below defines the key characteristics to consider for antenna selection. Table 11. AirPrime AR7552 WWAN Antenna Recommendations Characteristics WCDMA B5 LTE B5 WCDMA B2 LTE B2 LTE B4 LTE B7 LTE B17 Frequency (MHz) TX 824-849 1850-1910 1710 – 1755 2500-2570 704 – 716 RX 869-894 1930-1990 2110 – 2155 2620-2690 734– 746 Impedance RF 50 Ω DC 10 kΩ ±1k VSWR max RX 1.5: 1 TX 1.5: 1 Polarization Linear, vertical Typical radiated gain 0 dBi in one direction at least
4117336 Rev 1.0 May 18, 2015 13 Hardware Integration Guide RF Specification 3.4. Primary Antenna Diagnostics The primary antenna diagnostic feature allows the AirPrime AR7552 embedded module to determine if the primary antenna connected to the module is: open, shorted or normal. The antenna connected to this interface needs to have a DC resistance to ground of 10 kΩ ± 1k embedded inside. The ARx55x FW accepts two limits which are used to evaluate the status of the antenna, representing the short and open thresholds. Refer to document [7] for the syntax of AT+ANTLIMT. Table 12. Primary Antenna ADC Characteristics Min Nom Max Units ADC Voltage Range 0 0.9 1.8 Volts Resolution - 15 Bit ADC Values 0 16383 Voltage/ADC step ~0.0011 Volts 1 Assumes 10kΩ Nominal DC resistance in the attached antenna and internal to AirPrime AR7552 device The following example illustrates the Antenna states and resistance values for a typical limit setting. AT+ANTLIMT=1,839,1088 Table 13. Primary Antenna Diagnostics Ranges Antenna State Min ADC Max ADC Antenna Resistance Range Short 0 839 ~ ≤ 7 kΩ Normal 841 1086 7 kΩ < x < 13 kΩ Open 1088 1900 ≥ 13 kΩ Note: Highlighted numbers in the table above are programmed as shortLim and openLim using the +ANTLIMT command. 3.5. RX2 Antenna Diagnostics The RX2 antenna diagnostic feature allows the AirPrime AR75520 to determine if the RX2 antenna connected to the module is: open, shorted or normal. The antenna connected to this interface needs to have a DC resistance to ground of 10 kΩ ± 1k embedded inside. The AirPrime AR7552 FW accepts two limits which are used to evaluate the status of the antenna, representing the short and open thresholds. Refer to document [7] for the syntax of AT+ANTLIMT. Table 14. RX2 Antenna ADC Characteristics Min Nom Max Units ADC Voltage Range 0 0.9 1.8 Volts Resolution - 15 Bit ADC Values 0 16383 Voltage/ADC step ~0.0011 Volts 1 Assumes 10kΩ Nominal DC resistance in the attached antenna and internal to AirPrime AR7552 device
4117336 Rev 1.0 May 18, 2015 14 Hardware Integration Guide RF Specification The following example illustrates the Antenna states and resistance values for a typical limit setting. AT+ANTLIMT=2,839,1088 Table 15. RX2 Antenna Diagnostics Ranges Antenna State Min ADC Max ADC Antenna Resistance Range Short 0 839 ~ ≤ 7 kΩ Normal 841 1086 7 kΩ < x < 13 kΩ Open 1088 1900 ≥ 13 kΩ Note: Highlighted numbers in the table above are programmed as shortLim and openLim using the +ANTLIMT command.
4117336 Rev 1.0 May 18, 2015 15 4. Audio The AirPrime AR7552 supports both Analog and Digital audio interfaces. The following diagram illustrates the Audio subsystem and identifies where various AT commands affect the audio subsystem. Refer to document [7] for details of the AT commands. 4.1. Analog Audio The AirPrime AR7552 provides a mono differential analog audio interface. Table 16. Analog Audio Interface Pads Pad Name Direction Function Interface CD9 AUDIO1_IN_P Input Microphone 1 input positive Primary CC10 AUDIO1_IN_M Microphone 1 input negative CE6 AUDIO1_OUT_P Output Speaker 1 output positive CE8 AUDIO1_OUT_M Speaker 1 output negative Table 17. Analog Audio Interface Characteristics Analog Audio Min. Typ. Max. Units Audio IN Input Impedance 16 20 24 kΩ Signal Level – Differential -0.3 - 2.9 dBV Signal Level – Single-ended (the unused audio signal must be tied to GND or analog reference) -0.3 - 2.9 dBV Audio OUT Signal Level – Differential - - dBV Signal Level – Single-ended -0.3 - 2.9 dBV Output Impedance -0.3 - 2.9 Ω Signal Drive Strength – Application Load - 600 1M kΩ
4117336 Rev 1.0 May 18, 2015 16 Hardware Integration Guide Audio 4.2. Digital Audio The AirPrime AR7552 provides a 4-wire digital audio interface. This interface can be configured as either a PCM or an I2S. Table 18. Digital Audio Interface Pads Pad Name Direction1 PCM Function Direction I2S Function If Unused DB3 PCM_FS Output PCM Frame Sync Input/Output I2S_WS Leave Open DA3 PCM_CLK Output PCM Clock Input/Output I2S_SCLK Leave Open DC2 PCM_DOUT Output PCM Data Out Output I2S_DOUT Leave Open DD2 PCM_DIN Input PCM Data In Input I2S_DIN Leave Open 1 Direction when defined in Master mode.
4117336 Rev 1.0 May 18, 2015 17 5. Routing Constraints and Recommendations Layout and routing of the AirPrime AR7552 device in the application is critical to maintaining the performance of the radio. The following sections provide guidance to the developer when designing their application to include an AirPrime AR7552 device and achieve optimal system performance. 5.1. RF Routing Recommendations To route the RF antenna signals, the following recommendations must be observed for PCB layout: The RF signals must be routed using traces with a 50  characteristic impedance. Basically, the characteristic impedance depends on the dielectric constant (εr) of the material used, trace width (W), trace thickness (T), and height (H) between the trace and the reference ground plane. In order to respect this constraint, Sierra Wireless recommends that a MicroStrip structure be used and trace width be computed with a simulation tool (such as AppCAD, shown in the figure below and available free of charge at http://www.avagotech.com). Figure 1. AppCAD Screenshot for Microstrip Design Power Mode Diagram The trace width should be wide enough to maintain reasonable insertion loss and manufacturing reliability. Cutting out inner layers of ground under the trace will increase the effective substrate height; therefore, increasing the width of the RF trace. Caution: It is critical that no other signals (digital, analog, or supply) cross under the RF path. The figure below shows a generic example of good and poor routing techniques.
4117336 Rev 1.0 May 18, 2015 18 Hardware Integration Guide Routing Constraints and Recommendations Poor routing Correct routing The yellow traces cross the RF trace. There is no signal around the RF path. Figure 2. RF Routing Examples  Fill the area around the RF traces with ground and ground vias to connect inner ground layers for isolation.  Cut out ground fill under RF signal pads to reduce stray capacitance losses.  Avoid routing RF traces with sharp corners. A smooth radius is recommended. E.g. Use of 45° angles instead of 90°.  The ground reference plane should be a solid continuous plane under the trace.  The coplanar clearance (G, below) from the trace to the ground should be at least the trace width (W) and at least twice the height (H). This reduces the parasitic capacitance, which potentially alters the trace impedance and increases the losses. E.g. If W = 100 microns then G = 200 microns in an ideal setup. G = 150 microns would also be acceptable is space is limited. Figure 3. Coplanar Clearance Example Note: The figure above shows several internal ground layers cut out, which may not be necessary for every application.
4117336 Rev 1.0 May 18, 2015 19 Hardware Integration Guide Routing Constraints and Recommendations Figure 4. Antenna Microstrip Routing Example 5.2. Power and Ground Recommendations Power and ground routing is critical to achieving optimal performance of the AirPrime AR7552 devices when integrated into an application. Recommendations:  Do not use a separate GND for the Antennas  Connections to GND from the AirPrime AR7552 should be flooded plane using thermal reliefs to ensure reliable solder joints.  VBATT is recommended to be routed as a wide trace(s) directly from the 4V supply to the LGA pad. 5.3. Antenna Recommendations The AirPrime AR755x devices are designed to provide diagnostics status of the antennas connected to it.  The Primary antenna interface is optimized for a multiband cellular antenna with a 10 kΩ DC impedance between the antenna element and the ground reference.  The GNSS antenna interface is optimized for a 5V active GNSS antenna supporting the GPS L1 and GLONASS L1 FDMA bands. Refer to GNSS Antenna Diagnostics section. Connecting the antenna ground reference to the vehicle chassis is not recommended since that has been known to cause noise from the engine to couple into the audio of the device. It is ultimately up to the integrator to evaluate this performance.
4117336 Rev 1.0 May 18, 2015 20 Hardware Integration Guide Routing Constraints and Recommendations 5.4. Interface Circuit Recommendations The recommended interface implementation is to use open-drain non-inverting buffers with pull-ups to the appropriate voltage reference. This allows a host processor operating at a different voltage to communicate with the AirPrime AR7552 using the appropriate voltage levels. The figure below is a reference circuit for a digital input signal to the AirPrime AR7552 device. OVTVCCOutput from AppInput to AirPrime AR moduleVCC_1V8Vref of APP Figure 5. AirPrime AR7552 Input Reference Circuit The figure below is a reference circuit for a digital output signal from the AirPrime AR7552 device. OVTVCC Output from AirPrime AR moduleInput to AppVref of APPVCC_1V8 Figure 6. AirPrime AR7552 Output Reference Circuit The open-drain non-inverting buffer used in the reference circuits above is the OnSemi NL17SZ07. Tip: The NL17SZ07 is over-voltage tolerant on the inputs. It may be possible to power all the buffers from the 1.8V reference voltage output. Review the digital output characteristics of the applications drivers and the Input characteristics of the buffer selected to determine if this would work in your application. If a Digital IO signal is used bidirectional in the application then a bidirectional buffer or bidirectional level translator is needed. Note: The AR7552 modem is granted with a modular approval for mobile applications. During FCC/IC testing, the antenna trace of the AirPrime AR7552 embedded module which located on the CCB are defined in the table below.
4117336 Rev 1.0 May 18, 2015 21 Hardware Integration Guide Routing Constraints and Recommendations Table 19. The specification of RF Trace of The CCB, Main Port Length-1 (mm) Length-2 (mm) Length-3 (mm) Angel 1 (degree) Angel 2 (degree) Width (mm) Main Port 3.9 19.79 5.86 135 135 1.58 Table 20. The specification of RF Trace of The CCB, Diversity and GPS Port Length (mm) Width (mm) Diversity Port 24.35 1.58 GPS Port 27.01 1.58 * Diversity Port is for Rx only. The figure below is the RF trace in AR7552 CCB. Figure 7. The definition of RF trace in the AR7552 CCB Integrators may use the AR7552 modem in their final products without additional FCC/IC (Industry Canada) certification if they meet the above design in AR7552 CCB. Otherwise, FCC/IC Class II Permissive change need be obtained.Angel 1 Angel 2
4117336 Rev 1.0 May 18, 2015 22 6. Regulatory Information 6.1. Important Notice Because of the nature of wireless communications, transmission and reception of data can never be guaranteed. Data may be delayed, corrupted (i.e., have errors) or be totally lost. Although significant delays or losses of data are rare when wireless devices such as the Sierra Wireless modem are used in a normal manner with a well-constructed network, the Sierra Wireless modem should not be used in situations where failure to transmit or receive data could result in damage of any kind to the user or any other party, including but not limited to personal injury, death, or loss of property. Sierra Wireless and its affiliates accept no responsibility for damages of any kind resulting from delays or errors in data transmitted or received using Sierra Wireless modem, or for failure of the Sierra Wireless modem to transmit or receive such data. 6.2. Safety and Hazards Do not operate the AR7552 modem:  In areas where blasting is in progress  Where explosive atmospheres may be present including refueling points, fuel depots, and chemical plants  Near medical equipment, life support equipment, or any equipment which may be susceptible to any form of radio interference. In such areas, the AR Series device MUST BE POWERED OFF. Otherwise, the AR Series device can transmit signals that could interfere with this equipment  In an aircraft, the AR Series device MUST BE POWERED OFF. Otherwise, the AR Series device can transmit signals that could interfere with various onboard systems and may be dangerous to the operation of the aircraft or disrupt the cellular network. Use of cellular phone in aircraft is illegal in some jurisdictions. Failure to observe this instruction may lead to suspension or denial of cellular telephone services to the offender, or legal action or both.  Some airlines may permit the use of cellular phones while the aircraft is on the ground and the door is open. The AR Series device may be used normally at this time. 6.3. Important Compliance Information for USA OEM Integrators The AR Series device is granted with a modular approval for mobile applications. Integrators may use the AR Series device in their final products without additional FCC/IC (Industry Canada) certification if they meet the following conditions. Otherwise, additional FCC/IC approvals must be obtained. 1. At least 20cm separation distance between the antenna and the user’s body must be maintained at all times. 2. To comply with FCC/IC regulations limiting both maximum RF output power and human exposure to RF radiation, the maximum antenna gain including cable loss in
4117336 Rev 1.0 May 18, 2015 23 Hardware Integration Guide Regulatory Information a mobile-only exposure condition must not exceed the gain values presented in the table below:  5.0 dBi in Cellular band  5.0 dBi in PCS band  5.0 dBi in LTE Band 4  7.0 dBi in LTE Band 7  5.0 dBi in LTE Band 17 3. The AR7552 modem may transmit simultaneously with other collocated radio transmitters within a host device, provided the following conditions are met:  Each collocated radio transmitter has been certfied by FCC / IC for mobile application.  At least 20 cm separation distance between the antennas of the collocated transmitters and the user’s body must be maintained at all times.  The output power and antenna gain must not exceed the limits and configu-rations stipulated in the following table. Device Technology Band Frequency (MHz) Maximum conducted power Maximum antenna gain AR7552 Module LTE 2 1850-1910 25.0 5 4 1710-1755 25.0 5 5 824-849 25.0 5 7 2500 – 2570 25.7 7 17 704-716 25.0 5 UMTS 2 1850-1910 25.7 5 5 824-849 25.7 5 Collocated transmitters1 WLAN 2400-2500 29 5 5150-580 29 5 WiMAX 2300-2400 29 5 2500-2700 29 5 3300-3800 29 5 BT 2400-2500 15 5 1. Valid collocated Transmitter combinations: WLAN+BT; WiMAX+BT. (WLAN+WiMAX+BT is not permitted.) 4. A label must be affixed to the outside of the end product into which the AirPrime AR7552 device is incorporated, with a statement similar to the following: This device contains FCC ID: N7NAR7552 This equipment contains equipment certified under IC: 2417C-AR7552 5. A user manual with the end product must clearly indicate the operating requirements and conditions that must be observed to ensure compliance with current FCC/IC RF exposure guidelines. The end product with an embedded AirPrime AR7552 device may also need to pass the FCC Part 15 unintentional emission testing requirements and be properly authorized. Note: If this module is intended for use in a portable device, you are responsible for separate approval to satisfy the SAR requirements of FCC Part 2.1093 and IC RSS-102.
4117336 Rev 1.0 May 18, 2015 24 7. References 7.1. Reference Documents The table below lists the reference specifications for this product. Table 21. Reference Specifications Ref Title Issuer [1] Recommended Minimum Performance Standards for cdma2000 High Rate Packet Data Access Terminal – C.S0033 3GPP2 [2] Recommended Minimum Performance Standards for cdma2000 Spread Spectrum Mobile Stations – C.S0011 (IS-98D) 3GPP2 [3] Universal Serial Bus Specification USB Implementers Forum [4] Universal Serial Bus CDC Subclass Specification for Wireless Mobile Communication Devices USB Implementers Forum [5] Universal Serial Bus Class Definitions for Communication Devices USB Implementers Forum [6] AirPrime AR Series Customer Process Guidelines Sierra Wireless [7] AirPrime AR7 Series AT Command Interface Specification Sierra Wireless [8] AirPrime AR7 Series Firmware Download Guide Sierra Wireless 7.2. Abbreviations The table below lists several abbreviations used in this document. Table 22. Abbreviations Abbreviation Description CDMA Code Division Multiple Access DRX Discontinuous Receive GNSS Global Navigation Satellite System GSM Global System for Mobile Communications HSPA High Speed Packet Access LTE Long Term Evolution SCI Slot Cycle Index USB Universal Serial Bus WCDMA Wideband Code Division Multiple Access WWAN Wireless Wide Area Network

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