B GS F110 G N26 SP 10T An tenna S wi tc h Mo dul e wi th G PI O I nte rface , 2 G S MT X Por ts fo r mul ti - mod e GS M/ E D G E, WC D M A o r LTE Ap pli cations Mai n RF F ront end A pplic ati on s Applic atio n N ote A N 306 Revision: Rev. 1.0 2014-11-28 RF and P r otecti on D evic es Edition 2015-01-21 Published by Infineon Technologies AG 81726 Munich, Germany © 2015 Infineon Technologies AG All Rights Reserved. LEGAL DISCLAIMER THE INFORMATION GIVEN IN THIS APPLICATION NOTE IS GIVEN AS A HINT FOR THE IMPLEMENTATION OF THE INFINEON TECHNOLOGIES COMPONENT ONLY AND SHALL NOT BE REGARDED AS ANY DESCRIPTION OR WARRANTY OF A CERTAIN FUNCTIONALITY, CONDITION OR QUALITY OF THE INFINEON TECHNOLOGIES COMPONENT. THE RECIPIENT OF THIS APPLICATION NOTE MUST VERIFY ANY FUNCTION DESCRIBED HEREIN IN THE REAL APPLICATION. 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BGSF110GN26 Antenna Switch Module with integrated GPIO interface Application Note AN306 Revision History: 2014-11-28 st Previous Revision: Not applicable; this is 1 version Page Subjects (major changes since last revision) Trademarks of Infineon Technologies AG AURIX™, C166™, CanPAK™, CIPOS™, CIPURSE™, CoolGaN™, CoolMOS™, CoolSET™, CoolSiC™, CORECONTROL™, CROSSAVE™, DAVE™, DI-POL™, DrBLADE™, EasyPIM™, EconoBRIDGE™, EconoDUAL™, EconoPACK™, EconoPIM™, EiceDRIVER™, eupec™, FCOS™, HITFET™, HybridPACK™, ISOFACE™, IsoPACK™, i-Wafer™, MIPAQ™, ModSTACK™, my-d™, NovalithIC™, OmniTune™, OPTIGA™, OptiMOS™, ORIGA™, POWERCODE™, PRIMARION™, PrimePACK™, PrimeSTACK™, PROFET™, PROSIL™, RASIC™, REAL3™, ReverSave™, SatRIC™, SIEGET™, SIPMOS™, SmartLEWIS™, SOLID FLASH™, SPOC™, TEMPFET™, thinQ!™, TRENCHSTOP™, TriCore™. Other Trademarks Advance Design System™ (ADS) of Agilent Technologies, AMBA™, ARM™, MULTI-ICE™, KEIL™, PRIMECELL™, REALVIEW™, THUMB™, µVision™ of ARM Limited, UK. ANSI™ of American National Standards Institute. AUTOSAR™ of AUTOSAR development partnership. Bluetooth™ of Bluetooth SIG Inc. CAT-iq™ of DECT Forum. COLOSSUS™, FirstGPS™ of Trimble Navigation Ltd. EMV™ of EMVCo, LLC (Visa Holdings Inc.). EPCOS™ of Epcos AG. FLEXGO™ of Microsoft Corporation. HYPERTERMINAL™ of Hilgraeve Incorporated. MCS™ of Intel Corp. IEC™ of Commission Electrotechnique Internationale. IrDA™ of Infrared Data Association Corporation. ISO™ of INTERNATIONAL ORGANIZATION FOR STANDARDIZATION. MATLAB™ of MathWorks, Inc. MAXIM™ of Maxim Integrated Products, Inc. MICROTEC™, NUCLEUS™ of Mentor Graphics Corporation. MIPI™ of MIPI Alliance, Inc. MIPS™ of MIPS Technologies, Inc., USA. muRata™ of MURATA MANUFACTURING CO., MICROWAVE OFFICE™ (MWO) of Applied Wave Research Inc., OmniVision™ of OmniVision Technologies, Inc. Openwave™ of Openwave Systems Inc. RED HAT™ of Red Hat, Inc. RFMD™ of RF Micro Devices, Inc. SIRIUS™ of Sirius Satellite Radio Inc. SOLARIS™ of Sun Microsystems, Inc. SPANSION™ of Spansion LLC Ltd. Symbian™ of Symbian Software Limited. TAIYO YUDEN™ of Taiyo Yuden Co. TEAKLITE™ of CEVA, Inc. TEKTRONIX™ of Tektronix Inc. TOKO™ of TOKO KABUSHIKI KAISHA TA. UNIX™ of X/Open Company Limited. VERILOG™, PALLADIUM™ of Cadence Design Systems, Inc. VLYNQ™ of Texas Instruments Incorporated. VXWORKS™, WIND RIVER™ of WIND RIVER SYSTEMS, INC. ZETEX™ of Diodes Zetex. Last Trademarks Update 2014-07-17 Application Note AN306, Rev. 1.0 3 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface List of Content, Figures and Tables Table of Contents 1 Introduction ........................................................................................................................................ 6 2 2.1 2.2 2.3 2.4 BGSF110GN26 Features .................................................................................................................... 6 Main Features ...................................................................................................................................... 6 Functional Diagram .............................................................................................................................. 6 Pin Configuration .................................................................................................................................. 7 Pin Description ..................................................................................................................................... 7 3 3.1 Application .......................................................................................................................................... 8 Application Board ................................................................................................................................. 9 4 4.1 4.2 4.3 4.4 4.5 Small-Signal Characteristics ........................................................................................................... 10 Insertion Loss from Antenna Port to Respective RF Ports ................................................................ 10 Forward transmission GSM Tx........................................................................................................... 11 Reflection Antenna Port to all Ports ................................................................................................... 13 Port Reflection GSM Tx Ports ............................................................................................................ 14 Isolation .............................................................................................................................................. 15 5 5.1 5.1.1 5.1.2 5.1.3 Non-Linear Performance of BGSF110GN26 .................................................................................. 16 Intermodulation................................................................................................................................... 16 Intermodulation Measurement Setup ................................................................................................. 17 Intermodulation Measurement conditions .......................................................................................... 18 IMD Test Results for Band 1 and 5 .................................................................................................... 18 6 6.1.1 Harmonic Distortion ......................................................................................................................... 19 Harmonic Generation Measurement conditions ................................................................................. 19 7 Abbreviations ................................................................................................................................... 21 8 Authors .............................................................................................................................................. 22 Application Note AN306, Rev. 1.0 4 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface List of Content, Figures and Tables List of Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 BGSF110GN26 functional diagram..................................................................................................... 6 BGSF110GN26 pin configuration ......................................................................................................... 7 BGSF110GN26 in a mobile phone front end ....................................................................................... 8 Layout of the application board ............................................................................................................ 9 Layout of de-embedding “ through” and “half” boards ......................................................................... 9 PCB layer information ........................................................................................................................ 10 Application circuit ............................................................................................................................... 10 Forward transmission antenna port to TRx ports ............................................................................... 11 Forward transmission GSM Tx ports.................................................................................................. 12 Forward transmission TRx2 over temperature ................................................................................... 12 Reflection antenna port to all TRx ports ............................................................................................ 13 Port reflection GSM Tx ports .............................................................................................................. 14 Isolation neighbour ports .................................................................................................................... 15 Isolation TRx to TX1 port ................................................................................................................... 15 Isolation TRx to Rx2 port .................................................................................................................... 16 Block diagram of RF switch intermodulation ...................................................................................... 17 Intermodulation measurement test setup ........................................................................................... 17 Set-up for harmonics measurement ................................................................................................... 19 Harmonics at fin=824 MHz .................................................................................................................. 20 Harmonics at fin=1710MHz ................................................................................................................. 20 List of Tables Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Pin description (top view) ..................................................................................................................... 7 Insertion loss from antenna port to RF ports (all other ports terminated with 50Ohm resistance) .. 10 Insertion loss from antenna port to GSM Tx ports (all other ports terminated with 50 Ohm resistance) .......................................................................................................................................... 11 Return loss from antenna port to RF ports (all other ports terminated with 50Ohm resistance) ....... 13 Return loss from antenna port to GSM Tx ports (all other ports terminated with 50-Ohm resistance)14 Test conditions of IMD measurements............................................................................................... 18 IMD measurements ............................................................................................................................ 18 Harmonic generation measurement conditions ................................................................................. 19 Application Note AN306, Rev. 1.0 5 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Introduction Introduction 1 The BGSF110GN26 is a Single-Pole Ten-Throw (SP10T) Antenna Switch Module (ASM) optimized for mobile phone and wireless applications for operating frequencies up to 3.8 GHz. It is a perfect solution for multi-mode handsets based on quadband GSM, WCDMA and LTE. The switch module configuration is shown in Figure 1 and supports a wide supply voltage range of 2.4 to 3.3 V. The module comes in a miniature TSNP package and is comprised of a high power CMOS SP10T switch, an integrated GPIO controller, and harmonic filters for GSM low-band and high-band transmit paths. The on-chip controller integrates CMOS logic and level shifters, driven by control inputs from 1.35 to 3.1 V. External DC blocking capacitors are not required in typical applications provided that DC voltages are not applied to any RF port. 2 BGSF110GN26 Features 2.1 Main Features • • • • • • • • • • Suitable for multi-mode GSM / EDGE / WCDMA / LTE / LTE-Advanced applications Frequency range of 100 MHz to 2.7 GHz Ultra-low insertion loss Integrated GSM transmit filters 8 interchangeable, high-linearity WCDMA TRX ports 2 high-linearity GSM TX paths High port-to-port isolation Integrated MIPI RFFE interface No DC decoupling capacitors required, if no DC applied on RF lines Small form factor: 3.2 mm x 2.8 mm x 0.73 mm 2.2 Functional Diagram ANT TRX1 TRX2 TX_HB TRX3 TRX4 Harmonic Filters TRX5 TRX6 TX_LB TRX7 TRX8 SP10T GND VDD V4 V3 V2 V1 GPIO Controller BGSF110G_Functional_Diagram.vsd Figure 1 BGSF110GN26 functional diagram Application Note AN306, Rev. 1.0 6 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface BGSF110GN26 Features 2.3 Pin Configuration GND TRX3 TRX2 TRX1 TRX7 GND TRX8 21 GND 14 VDD TX1 V4 GND PG-TSNP-26-2 3.4 x 2.6 mm 400 µm pad pitch V3 GND V2 V1 TX2 26 GND 8 1 GND TRX4 TRX5 TRX6 Figure 2 BGSF110GN26 pin configuration 2.4 Pin Description Table 1 GND GND ANT GND Pin description (top view) Pin NO Name Pin Type Function 0 1 GND GND 2 TRX4 GND GND I/O Ground, die pad DC ground WCDMA TRX port 3 TRX5 I/O WCDMA TRX port 4 5 TRX6 GND GND I/O WCDMA TRX port GND GND RF ground RF ground 8 ANT GND I/O GND Antenna port RF ground 9 GND GND RF ground 6 7 10 TX2 I GSM HB port 11 GND GND GND GND RF ground RF ground TX1 GND I GND I/O GSM LB port RF ground 12 13 14 15 16 TRX8 GND 17 TRX7 GND I/O 18 TRX1 I/O 19 TRX2 I/O WCDMA TRX port WCDMA TRX port 20 TRX3 I/O WCDMA TRX port Application Note AN306, Rev. 1.0 7 / 23 WCDMA TRX port RF ground WCDMA TRX port 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Application Table 1 Pin description (top view) Pin NO Name Pin Type Function 21 GND GND DC ground 22 VDD PWR Supply Voltage 23 V4 I GPIO Control pin 24 V3 I GPIO Control pin 25 V2 I GPIO Control pin 26 V1 I GPIO Control pin Application 3 A typical use of the BGSF110GN26 ASM in a mobile-phone application is shown in Figure 3. In the main antenna path of the RF front end, the Infineon BGSF110GN26 routes the antenna signal to the required banddependent front end components (e.g. duplexers, filters, PA), which in turn are connected directly to the transceiver IC. For the diversity path, Infineon recommends its RF switches such as the BGS15AN16. Infineon also offers a broad portfolio of Low-Noise Amplifiers (LNAs) that are optimized for the receive path in mobilephone applications. Infineon ASM BGSF110GN26 Main Infineon RF Switch Diversity ASM Infineon LNAs BGAxx Transceiver Figure 3 BGSF110GN26 in a mobile phone front end Application Note AN306, Rev. 1.0 8 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Application 3.1 Application Board Shown below is a picture of the EValuation Board (EVB) used for all measurements (Figure 4). This EVB is designed such that all 50-Ohm connecting lines have the same length. In order to obtain accurate values for insertion loss measurements of the BGSF110GN26, all influences and losses of the EVB, lines, and connectors have to be eliminated. Therefore a separate de-embedding board representing the line length is necessary (Figure 5). The calibration of the NetWork Analyser (NWA) is done in six steps: 1) Perform full calibration on all NWA ports. 2) Attach special SMA connector (use same as soldered to EVB with no inner conductor) to port 2 and perform “open” port extension. Turn the port extensions on. 3) Connect the “half” de-embedding board (Figure 5 right board) between port 1 and port 2, and store this as an s-parameter (.s2p) file. Now turn all port extensions off. 4) Load the stored s-parameter file of the “half” de-embedding board as the de-embedding file for all NWA ports used. 5) Now switch all port extentions on. 6) Cross-check the insertion loss with the “through” de-embedding board (Figure 5 left board) Please note: On PCB, TRx7 is Rx 1 and TRx 8 is Rx2 Figure 4 Layout of the application board Figure 5 Layout of de-embedding “ through” and “half” boards The EVB is made of a sandwich of FR4 and Rogers 04002, and has 3 layers. The layer stack is shown in Figure 6. Application Note AN306, Rev. 1.0 9 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Small-Signal Characteristics Vias Rogers04002 , 0.2mm Copper 35µm FR4, 0.7mm Figure 6 PCB layer information 4 Small-Signal Characteristics The small-signal characteristics were measured at 25 °C using a Vector Network Analyzer (VNA), a supply voltage, Vdd, of 3.0 V, and the application circuit shown in Figure 7. ANT BGS18MN14 SP8T 27nH Figure 7 Application circuit 4.1 Insertion Loss from Antenna Port to Respective RF Ports Table 2 Frequency (MHz) Insertion loss from antenna port to RF ports (all other ports terminated with 50Ohm resistance) 704 716 740 751 824 881 TRx1 0.62 0.62 0.61 TRx2 0.63 0.62 TRx3 0.65 TRx4 0.61 0.6 0.6 0.59 0.6 0.69 0.71 0.73 0.73 0.75 0.79 0.8 0.89 1 1.1 1.7 0.62 0.62 0.6 0.6 0.6 0.6 0.68 0.7 0.72 0.72 0.74 0.77 0.78 0.85 0.99 1.1 1.7 0.64 0.64 0.64 0.61 0.61 0.61 0.61 0.67 0.68 0.7 0.7 0.71 0.75 0.76 0.83 0.97 1 1.6 0.63 0.62 0.62 0.62 0.6 0.6 0.6 0.7 0.72 0.72 0.73 0.77 0.78 0.86 1 1.1 1.8 TRx5 0.62 0.61 0.61 0.61 0.61 0.62 0.62 0.62 0.74 0.75 0.76 0.76 0.77 0.81 0.82 0.9 1.1 1.2 2 TRx6 0.59 0.59 0.58 0.58 0.57 0.57 0.57 0.57 0.72 0.75 0.79 0.79 0.82 0.88 1 1.3 1.4 2.3 TRx7 (Rx1) 0.62 0.61 0.61 0.61 0.6 0.61 0.61 0.61 0.73 0.74 0.75 0.75 0.76 0.79 0.79 0.85 0.98 1 1.7 TRx8 (Rx2) 0.63 0.62 0.62 0.62 0.59 0.59 0.59 0.59 0.72 0.71 0.71 0.71 0.72 0.75 0.76 0.84 0.98 1 1.6 Application Note AN306, Rev. 1.0 915 0.6 942 1710 1842 1960 1970 2017 2140 2170 2350 2593 2690 3500 0.68 10 / 23 0.9 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Small-Signal Characteristics Forward Transmission TRx ports 0 Forward Transmission (dB) 0.704 GHz -0.5907 dB 2.14 GHz -0.7452 dB -0.5 -1 2.14 GHz -0.8789 dB 3.5 GHz -1.553 dB -1.5 -2 -2.5 DB(|S(2,1)|) TRX1 DB(|S(2,1)|) TRX4 DB(|S(2,1)|) RX1 DB(|S(2,1)|) TRX2 DB(|S(2,1)|) TRX5 DB(|S(2,1)|) RX2 DB(|S(2,1)|) TRX3 DB(|S(2,1)|) TRX6 3.5 GHz -2.34 dB -3 0 1 2 Frequency (GHz) Figure 8 Forward transmission antenna port to TRx ports 4.2 Forward transmission GSM Tx Table 3 Frequency (MHz) Tx1(LB) Tx2(HB) 3 4 Insertion loss from antenna port to GSM Tx ports (all other ports terminated with 50 Ohm resistance) 704 716 0.69 0.69 1 1 740 751 0.71 0.71 1 824 881 915 0.75 0.79 0.81 0.82 1.1 1.2 1.3 1.3 1.4 1.9 2.1 4 8.5 11 47 1 0.97 0.96 0.97 43 31 28 28 28 28 28 30 36 41 25 1 Application Note AN306, Rev. 1.0 942 1710 1842 1960 1970 2017 2140 2170 2350 2593 2690 3500 11 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Small-Signal Characteristics Forward Transmission Tx ports 0 Forward Transmission (dB) HB -10 LB 1.862 GHz -1.193 dB 0.883 GHz -0.7937 dB -20 -30 -40 1.714 GHz -43.18 dB -50 2.729 GHz -42.78 dB -60 0.0003 3.476 GHz -50.61 dB 2 4 6 Frequency (GHz) Figure 9 Forward transmission GSM Tx ports 0 TRx2 , -20 ° -0.2 TRx2, 25° Forward Transmission -0.4 TRx2, 85 ° -0.6 -0.8 -1 -1.2 500 1000 1500 2000 2500 3000 Frequency Figure 10 Forward transmission TRx2 over temperature Application Note AN306, Rev. 1.0 12 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Small-Signal Characteristics 4.3 Reflection Antenna Port to all Ports Table 4 Frequency (MHz) Return loss from antenna port to RF ports (all other ports terminated with 50Ohm resistance) 704 716 740 751 824 881 TRx1 17.3 17.4 17.7 17.7 18.4 18.7 18.8 18.9 20.2 20.5 20.3 20.3 20.1 19.4 19.1 17.5 15 TRx2 17.3 17.4 17.6 17.7 18.4 18.7 18.8 18.8 19.8 20.1 20.1 20.1 19.5 19.4 18.1 15.7 14.6 10.3 TRx3 16.9 17.1 17.4 17.5 18.4 19.4 22.1 21.7 21.7 21.3 20.2 19.9 17.8 15.1 14.1 10.2 TRx4 17.5 17.7 18 18.1 18.9 19.4 19.6 19.7 20.7 20.8 20.4 20.4 20.1 19.1 18.8 17 14.6 13.5 TRx5 17.9 17.9 18 18 18.1 17.9 17.8 17.7 17.5 18.1 18.5 18.5 18.6 18.4 18.3 17.2 14.6 13.4 8.24 TRx6 18.9 19.1 19.5 19.6 20.4 20.7 20.7 20.8 17.3 16.4 16.4 16 14.9 14.7 13.1 11.1 10.4 7.05 TRx7 (Rx1) 17.5 17.6 17.8 17.8 18 18 18.1 18.1 17.9 16.6 15.5 10.2 TRx8 (Rx2) 17 17.2 17.5 17.6 18.6 20.1 19.8 17.7 15.2 14.3 10.8 19 18 915 19.2 942 1710 1842 1960 1970 2017 2140 2170 2350 2593 2690 3500 22 18 20 17.9 17.9 17.1 17.5 17.8 17.9 19.3 19.5 19.8 22.2 22.4 21.9 21.8 21.5 14 10.3 9 Reflection TR ports 0 Reflection (dB) -5 -10 -15 -20 -25 -30 0.0003 TRx1 TRx4 DB(|S(1,1)|) RX1 TRx2 TRx5 DB(|S(1,1)|) RX2 TRx3 Trx6 2 4 6 Frequency (GHz) Figure 11 Reflection antenna port to all TRx ports Application Note AN306, Rev. 1.0 13 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Small-Signal Characteristics 4.4 Port Reflection GSM Tx Ports Table 5 Return loss from antenna port to GSM Tx ports (all other ports terminated with 50-Ohm resistance) Frequency (MHz) 704 716 740 751 824 881 915 942 Tx1 (LB) 11.0 11.1 11.2 11.4 12.9 15.4 18.4 22.4 Tx2 (HB) 18.2 18.0 17.6 17.4 16.1 15.2 14.9 14.7 1710 13.1 1842 12.9 1960 1970 11.7 11.6 2017 10.8 Reflection TX ports 0 Reflection (dB) -10 HB LB -20 1.899 GHz -16.15 dB -30 -40 0.0003 2 4 6 Frequency (GHz) Figure 12 Port reflection GSM Tx ports Application Note AN306, Rev. 1.0 14 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Small-Signal Characteristics 4.5 Isolation Isolation_Neighbour_ TRx 0 -20 -40 -60 -80 -100 -120 0.0003 DB(|S(2,1)|) Isolation_RX1_tRX2 DB(|S(2,1)|) Isolation_TRX3_tTRX4 DB(|S(2,1)|) Isolation_TRX1_tTRX2 DB(|S(2,1)|) Isolation_TRX5_tTRX4 DB(|S(2,1)|) Isolation_TRX3_tTRX2 DB(|S(2,1)|) Isolation_TRX5_tTRX6 3 6 8.5 Frequency (GHz) Figure 13 Isolation neighbour ports Isolation TRx_to_Tx1 -20 -40 -60 -80 -100 -120 0.0003 DB(|S(2,1)|) Isolatio_RX2_tTX1 DB(|S(2,1)|) Isolation_TRX2_tTX1 DB(|S(2,1)|) Isolation_RX1_tTX1 DB(|S(2,1)|) Isolation_TRX3_tTX1 DB(|S(2,1)|) Isolation_sTRX6_tTX1 DB(|S(2,1)|) Isolation_TRX4_tTX1 DB(|S(2,1)|) Isolation_TRX1_tTX1 DB(|S(2,1)|) Isolation_TRX5_tTX1 2 4 6 Frequency (GHz) Figure 14 Isolation TRx to TX1 port Application Note AN306, Rev. 1.0 15 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Non-Linear Performance of BGSF110GN26 Isolation_TRx_to_Tx2 -20 -40 -60 -80 -100 DB(|S(2,1)|) Isolation_RX1_tTX2 DB(|S(2,1)|) Isolation_TRX1_tTX2 DB(|S(2,1)|) Isolation_RX2_tTX2 DB(|S(2,1)|) Isolation_TRX2_tTX2 DB(|S(2,1)|) Isolation_sTRX5_tTX2 DB(|S(2,1)|) Isolation_TRX3_tTX2 DB(|S(2,1)|) Isolation_sTRX6_tTX2 DB(|S(2,1)|) Isolation_TRX4_tTX2 -120 0.0003 2 4 6 Frequency (GHz) Figure 15 Isolation TRx to Rx2 port 5 Non-Linear Performance of BGSF110GN26 Smart phones today can operate across several cellular bands covering GSM / EDGE / CDMA / UMTS / WCDMA / LTE/TD-SCDMA / TD-LTE / LTE-A. The design of the RF front-end part in modern cellular phones is becoming increasingly complex and demanding due to the increasing number of frequency bands and modes that the phone needs to support. One of the main components of the RF front-end is the antenna switch that selects which transmitter (TX)/receiver (RX) path can be connected to the antenna. The RF switch has to satisfy high linearity requirements. The following material describes some of the main challenges of antenna switches in mobile applications. Modern smartphones are multi-mode devices that are capable of connecting to 2G, 3G and 4G networks. These networks often use different frequency bands. The smartphone’s RF frontend must therefore include bandspecific components. In order to appropriately route signals for a given mode and band of operation, a highperformance RF switch is an essential component of the front-end circuitry. The performance requirements of the RF swtich are discussed in the following sections. 5.1 Intermodulation Intermodulation Distortion (IMD2 and IMD3) is a parameter that describes the linearty of a device under multitone conditions. The intermodulation between different frequency components generates undesired output frequencies at the sum and difference frequencies of the input tones, and at multiples of those sum and difference frequencies. Application Note AN306, Rev. 1.0 16 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Non-Linear Performance of BGSF110GN26 Some of these possible intermodulation scenarios are shown in Figure 16. In this example, the transmitted (Tx) signal from the main antenna is coupled into the diversity antenna with high power. This signal (20 dBm) and a received jammer signal (-15 dBm) are entering the switch. Certain combinations of the TX and jammer frequencies are producing second- and third-order intermodulation products that fall into the desired reception band, and reduce the sensitivity of the receiver. Main BT WLAN Navigation Wifi FM diversity PA CB Radio TV ... PA PA Rx1 Tx1 Txn Rxn Rx1 Figure 16 Block diagram of RF switch intermodulation 5.1.1 Intermodulation Measurement Setup Rxn Rx2/3 Load -20dB -6 dB IMD Product reference Plane Tx Signal Generator Power Amplifier Circulator Blocker Signal Duplexer Tunable Bandpass Filter -3 dB ANT Phase Shifter / Delay Line DUT Tx -6dB* -20dB ANT Tunable Bandpass Filter Signal Generator Rx Signal Analyzer Figure 17 -6 dB Power reference plane regarding Specification Intermodulation measurement test setup Application Note AN306, Rev. 1.0 17 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Non-Linear Performance of BGSF110GN26 A requirement of the test setup for IMD measurements is high isolation between the RX and TX signals (Figure 17). In practice, a laboratory-grade duplexer with an isolation of 80 dB is used. Table 6 shows the test specification for Band 1 and Band 5. 5.1.2 Intermodulation Measurement conditions Table 6 Test conditions of IMD measurements Band 1 TX Test case FIN (MHz) PIN (dBm) CW IMD3 IMD2 low IMD2 high 1950 20 Interferer FIN (MHz) PIN (dBm) CW 1760 190 -15 4090 IMD product FIMD (MHz) 2140 Band 5 Test case FIN (MHz) PIN (dBm) CW IMD3 IMD2 low IMD2 high 835 20 FIN (MHz) 790 45 1715 PIN (dBm) CW FIMD (MHz) -15 880 The results for Band 1 and Band 5 are given in Table 7. 5.1.3 IMD Test Results for Band 1 and 5 Table 7 IMD measurements Band 1 TX Intermodulation Products UMTS Band 1 Interferer Test case FIN (MHz) PIN (dBm) FIN (MHz) PIN (dBm) FIMD (MHz) PIMD (dBm) IIPx (dBm) IMD3 IMD2 low IMD2 high 1950 1950 1950 20 20 20 1760 190 4090 -15 -15 -15 2140 2140 2140 -107 -93 -104 66 98 109 TX Band 5 Interferer Intermodulation Products UMTS Band 5 Test case FIN (MHz) PIN (dBm) FIN (MHz) PIN (dBm) FIMD (MHz) PIMD (dBm) IIPx (dBm) IMD3 835 20 790 -15 880 -123 74 IMD2 low IMD2 high 835 835 20 20 45 1715 -15 -15 880 880 -92 -105 97 110 Application Note AN306, Rev. 1.0 18 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Harmonic Distortion Harmonic Distortion 6 Harmonic distortion is another important parameter for the characterization of an RF switch. RF switches have to withstand high RF levels, up to 36 dBm. This high RF power at the input of a switch generates harmonics of the waveform that is present. These harmonics (2 nd rd and 3 ) can interfere with other reception bands or can cause distortion in other RF applications (GPS, WLan) within the mobile phone. . Load -20dB Directional Coupler -20dB Signal Generator Power Amplifier Circulator Tunable Bandpass Filter A Power meter Agilent E4419B -3dB B DUT ANT K&L -20dB Tunable Bandstop Filter Signal Analyzer Directional Coupler Figure 18 Set-up for harmonics measurement 6.1.1 Harmonic Generation Measurement conditions Table 8 Tx Harmonic generation measurement conditions Tx FIN (MHz) 824 1800 Harmonic Products FH2(MHz) FH3 (MHz) PIN (dBm), 50% DC 20…38 TX LB port 20…30 TRX LB ports 20…38 TX HB port 20…30 TRX HB ports 1648 2472 3600 5400 The results for the harmonic generation at 824 MHZ and 1710 MHz are shown in Figure 19 for TX1 and Figure 20 Tx2. The input power (Pin) is plotted on the x axis, and the generated harmonics in dBm on the y axis. Application Note AN306, Rev. 1.0 19 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Harmonic Distortion Harmicics [dBm] Harmonic HarmonicGeneration Gereration @ 824 MHz TX1 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 H2 H3 20 25 30 35 40 Pin [dBm] Figure 19 Harmonics at fin=824 MHz Harmonic HarmonicGeneration Gerneration@1710MHz Tx2 0 -10 Harmonics[dBm] -20 -30 -40 -50 H2 -60 H3 -70 -80 -90 20 25 30 35 40 Pin [dBm] Figure 20 Harmonics at fin=1710MHz Application Note AN306, Rev. 1.0 20 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Abbreviations 7 ASM CMOS EDGE FR4 GPIO GPS GSM LTE LTE-A PA PCB SMA Rodgers RF TD LTE TD-SCDMA TSNP UMTS W-CDMA WLAN Abbreviations Antenna Switch Module Complementary Metall-Oxide-Semiconductor Enhanced Data Rates for GMS Evolution Material for PCB General Purpose Input Output Global Positioning System Global System for Mobile Communication Long-Term Evolution LTE Advanced Power Amplifier Printed Circuit Board Sub Miniature version A Material for RF PCBs Radio Frequency Time Division LTE Time Division Synchronous Code Division Multiple Access Thin Small Non Leaded Package Universal Mobile Telecommunications System Wideband Code Division Multiple Access Wireless Local Area Network Application Note AN306, Rev. 1.0 21 / 23 2014-11-28 BGSF110GN26 Antenna Switch Module with integrated GPIO interface Authors 8 Authors Andre Dewai, Senior Application Engineer of the Business Unit “RF and Protection Devices” Ralph Kuhn, Senior Staff Application Engineer of the Business Unit “RF and Protection Devices” Application Note AN306, Rev. 1.0 22 / 23 2014-11-28 w w w . i n f i n e o n . c o m Published by Infineon Technologies AG AN306