L o w C o s t D V B - T /H L N A u s i n g BFR380 L3 Portable TV Applications App lication No te AN221 Revision 1.0, 2010-06-21 RF and Protect i on Devi ces Edition 2010-06-21 Published by Infineon Technologies AG 81726 Munich, Germany © 2010 Infineon Technologies AG All Rights Reserved. Legal Disclaimer The information given in this document shall in no event be regarded as a guarantee of conditions or characteristics. With respect to any examples or hints given herein, any typical values stated herein and/or any information regarding the application of the device, Infineon Technologies hereby disclaims any and all warranties and liabilities of any kind, including without limitation, warranties of non-infringement of intellectual property rights of any third party. Information For further information on technology, delivery terms and conditions and prices, please contact the nearest Infineon Technologies Office (www.infineon.com). Warnings Due to technical requirements, components may contain dangerous substances. For information on the types in question, please contact the nearest Infineon Technologies Office. Infineon Technologies components may be used in life-support devices or systems only with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system or to affect the safety or effectiveness of that device or system. Life support devices or systems are intended to be implanted in the human body or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may be endangered. Low Cost DVB-T/H Television LNA BFR380L3 Portable TV Applications Revision History: 2010-06-21, Revision 1.0 Previous Revision: Page Subjects (major changes since last revision) Trademarks of Infineon Technologies AG A-GOLD™, BlueMoon™, COMNEON™, CONVERGATE™, COSIC™, C166™, CROSSAVE™, CanPAK™, CIPOS™, CoolMOS™, CoolSET™, CONVERPATH™, CORECONTROL™, DAVE™, DUALFALC™, DUSLIC™, EasyPIM™, EconoBRIDGE™, EconoDUAL™, EconoPACK™, EconoPIM™, E-GOLD™, EiceDRIVER™, EUPEC™, ELIC™, EPIC™, FALC™, FCOS™, FLEXISLIC™, GEMINAX™, GOLDMOS™, HITFET™, HybridPACK™, INCA™, ISAC™, ISOFACE™, IsoPACK™, IWORX™, M-GOLD™, MIPAQ™, ModSTACK™, MUSLIC™, my-d™, NovalithIC™, OCTALFALC™, OCTAT™, OmniTune™, OmniVia™, OptiMOS™, OPTIVERSE™, ORIGA™, PROFET™, PRO-SIL™, PrimePACK™, QUADFALC™, RASIC™, ReverSave™, SatRIC™, SCEPTRE™, SCOUT™, S-GOLD™, SensoNor™, SEROCCO™, SICOFI™, SIEGET™, SINDRION™, SLIC™, SMARTi™, SmartLEWIS™, SMINT™, SOCRATES™, TEMPFET™, thinQ!™, TrueNTRY™, TriCore™, TRENCHSTOP™, VINAX™, VINETIC™, VIONTIC™, WildPass™, X-GOLD™, XMM™, X-PMU™, XPOSYS™, XWAY™. Other Trademarks AMBA™, ARM™, MULTI-ICE™, PRIMECELL™, REALVIEW™, THUMB™ of ARM Limited, UK. AUTOSAR™ is licensed by 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. FlexRay™ is licensed by FlexRay Consortium. HYPERTERMINAL™ of Hilgraeve Incorporated. 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. Mifare™ of NXP. MIPI™ of MIPI Alliance, Inc. MIPS™ of MIPS Technologies, Inc., USA. muRata™ of MURATA MANUFACTURING CO. OmniVision™ of OmniVision Technologies, Inc. Openwave™ Openwave Systems Inc. RED HAT™ Red Hat, Inc. RFMD™ RF Micro Devices, Inc. SIRIUS™ of Sirius Sattelite 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 Limited. Last Trademarks Update 2009-10-19 Application Note AN221 3 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 Table of Contents Table of Contents Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1 1.1 1.2 1.3 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External LNA and Diplexer Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bill of Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7 7 8 2 2.1 2.2 2.3 2.4 Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Gain Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Noise Figure Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 IP3 Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 S-Parameters Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3 PCB and Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Appendix 1: ESD protection circuit for system level ESD robustness . . . . . . . . . . . . . . . . . . . . 16 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Application Note AN221 4 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 List of Figures 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 External LNA and Diplexer Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Gain Set-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Noise Figure Measurement Set-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Noise Figure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 IP 3 Measurement Set-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 IP3 Measurement Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 S-Parameter Measurement Set-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 S-Parameters Measurement Results with 2.8 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 S-Parameters Measurement Results with 3.3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 S-Parameters Measurement Results with TUA9001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Application board with Tuner IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 PCB area of BFR380L3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Layout of the BFR380 PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 ESD test pulse according to system level specification IEC61000-4-2 – Contact Discharge 15kV 16 Smart 2-step ESD protection approach based on external and internal ESD protection structure 17 Standard ESD protection with optional ESD resistor, blocking capacitor and a serial inductor . . . 17 Application Note AN221 5 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 List of Tables List of Tables Table 1 Table 2 Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Application Note AN221 6 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 Introduction 1 Introduction This document provides information and measurement results of the external LNA including Diplexer designed for TV tuner ICs (e.g.TUA 9001).The DVB-T signal from the antenna is amplified and then separated with a diplexer for the VHF and UHF inputs of the tuner IC. The BFR380 application provides a excellent compromise between good noise performance and appropriate Intermodulation capability, and this combined with an outstanding cost / performance ratio. 1.1 External LNA and Diplexer Schematic Figure 1shows the schematic of the external LNA including the VHF / UHF Diplexer. This was designed to use the Infineon Tuner IC TUA9001 with a single antenna input. C104 100nF Vcc 2.8 L102 100nH R102 220Ω R105 22Ω C108 39p TR1 UHF R101 C102 1n 35k RFin R104 15Ω C101 L103 39n C105 2p7 LNA1 BFR380L3 330p B E C C106 22p L104 47n C109 39p TR2 Tuner IC TUA9001 C110 1n VHF C107 15p C111 1n L101 100 n Appl_Ckt380 .vsd R103 2R2 C103 68p Figure 1 External LNA and Diplexer Schematic 1.2 Bill of Material In Table 1 the BOM (bill of material) of the application is shown. The components with their function is the circuitry are described. Table 1 Component C101 Bill of material Value 330p Manufacturer/Type Function Various / 0402 DC blocking L101 100 nH Murata / LQW15 Protection R101 35k Various / 0402 Biasing Application Note AN221 7 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 Introduction Table 1 Bill of material (cont’d) Component Value Manufacturer/Type Function C102 1 nF Various / 0402 feedback R102 220 Various / 0402 feedback R103 2.2 Ω Various / 0402 Emitter biasing L102 100 nH Murata / LQW15 RF choke C103 68p Various / 0402 Emitter? C104 100n Various / 0402 DC blocking R104 15 Ω Various / 0402 Stability R105 22 Ω Various / 0402 Stability C105 2.7p Various / 0402 Diplexer L103 39n Murata / LQW15 Diplexer C106 22p Various / 0402 Diplexer L104 47nH Murata / LQW15 Diplexer C107 15p Various / 0402 Diplexer Tr1 Murata Conversion single ended to balanced TR2 Murata Conversion single ended to balanced C108 39p Various / 0402 DC blocking C109 39p Various / 0402 DC blocking Various / 0402 DC blocking Various / 0402 DC blocking C110 C111 1.3 1n 1n Power Consumption Table 2 shows the power consumption of the external LNA for 2.8 V and 3.3 V supply. Table 2 Power Consumption Voltage Current Power 2.8V 13.6mA 37.5mW 3.3V 16.8mA 55.4mW Application Note AN221 8 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 Measurements 2 Measurements For the measurements a TUA9001 daughter board was modified with VHF and UHF Test Points. To get real 50 Ohm the line to the baluns was cut and the test equipment was connected via a semirigid line. 2.1 Gain Measurement Figure 2 describes the test set-up of the gain measurement. The input loss pad is an attenuator to make a suitable 50 Ohm matching at the RF input of the daughter board. Signal generator Spectrum Analyser VHF Test Point and UHF Test Point RF Input DUT Loss Pad TUA900 x_ER_ gain_setup.vsd Figure 2 Gain Set-Up In the diagram Figure 3 the result for VHFand UHF are shown. All cable losses and the in- and output losses are compensated. Gain Ext LNA 16 14 12 Gain [dB] 10 3.3V 8 2.2V 6 4 2 0 0 100 200 300 400 500 600 Frequency [MHz] Figure 3 700 800 900 1000 TUA9001 _extLNA_Gain .vsd Gain Application Note AN221 9 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 Measurements 2.2 Noise Figure Measurement In Figure 4 the test set-up for the noise figure measurement is shown. The noise source is an 15 dB ENR device and the measurement is done according the y-method with a noise figure meter. Noise Figure Meter VHF Test Point and UHF Test Point DUT TUA900 x_ER_noise_setup.vsd Noise source Figure 4 Noise Figure Measurement Set-up The results for VHF and UHF are shown in Figure 5 Noise Figure Ext LNA 5 4.5 4 Noise Figure [dB] 3.5 3 2.2V 2.5 3.3V 2 1.5 1 0.5 0 0 100 200 300 400 500 600 Frequency [MHz] Figure 5 700 800 900 1000 TUA9001_ extLNA_NF.vsd Noise Figure Application Note AN221 10 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 Measurements 2.3 IP3 Measurement The set-up for the Intermodulation measurement for the 3rd order products is shown in Figure 6. Spectrum Analyser Signal generators VHF Test Point and UHF Test Point RF Input combiner DUT Input Loss Pad TUA900 x_ER_ IP3 _setup.vsd Figure 6 IP 3 Measurement Set-up With our automatic test software the IM3 product of both sides are measured, compared and the worse result is taken for the IIP3 calculation. The results of IP3 products are shown calculated as input intermodulation point 3th order (IIP3)in Figure 7 IIP3 Ext LNA 14 13 12 11 10 IIP3 [dBm] 9 8 3.3V 7 2.8V 6 5 4 3 2 1 0 0 100 200 300 400 500 600 Frequency [MHz] Figure 7 700 800 900 1000 TUA9001 _extLNA_IP3.vsd IP3 Measurement Results Application Note AN221 11 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 Measurements 2.4 S-Parameters Measurement In Figure 8 the test set-up for the S-Parameter measurement is shown. Network Analyzer VHF Test Point (UHF open) and UHF Test Point (VHF open) DUT TUA900 x_ ER_spara_setup.vsd Figure 8 S-Parameter Measurement Set-up The results of 2.8 V are shown in Figure 9 and the results of 3.3 V are shown in Figure 10. VHF S-Parameter S21, S11, S22 Figure 9 UHF S-Parameter S21, S11, S22 S-Parameters Measurement Results with 2.8 V Application Note AN221 12 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 Measurements UHF S-Parameter S21, S11, S22 VHF S-Parameter S21, S11, S22 Figure 10 S-Parameters Measurement Results with 3.3 V The results of S11 for VHF and UHF with attached TUA9001 at 2.8 V are shown in Figure 11. VHF S-Parameter S11 Figure 11 UHF S-Parameter S11 S-Parameters Measurement Results with TUA9001 Application Note AN221 13 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 PCB and Layout 3 PCB and Layout The PCB is realized as a RF daughter board, which can be connected to a base board. This gives the flexibility to operate different RF boards with the same base board. InFigure 12 the complete evaluation kit for the Tuner IC TUA9001 is shown. TUA9001_daughter_base.vsd Figure 12 Application board with Tuner IC In Figure 13 an excerpt of the LNA and diplexer area of the PCB is high lightened. Figure 13 PCB area of BFR380L3 The layout of the PCB is shown in Figure 14 Application Note AN221 14 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 PCB and Layout Figure 14 Layout of the BFR380 PCB Application Note AN221 15 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 Appendix 1: ESD protection circuit for system level ESD robustness Appendix 1: ESD protection circuit for system level ESD robustness Introduction With the advancement in miniaturization of semiconductor structures, ESD handling capability of the devices is becoming a concern. Increasing ESD handling capability of the I/O ports costs additional chip size and affects the I/O capacitance significantly. This is very important for high frequency devices, especially when high linearity is required. Therefore, tailored and cost effective ESD protection devices can be used to build up an ESD protection circuit. To handle ESD events during assembly, devices normally have on-chip ESD protection according to the device level standards e.g. “Human Body Model” JEDEC 22-A-115. To fulfill the much more stringent system level ESD requirements according to IEC61000-4-2 as shown in Figure 15, the external ESD protection circuit has to handle the majority of the ESD strike. The best external ESD protection is achieved using a TVS diode assisted by additional passive components. ESD_current, A 60 m6 Reference Pulse 15kV contact discharge according IEC61000-4-2 m6 time=1.507nsec ESD_current=57.68 A m7 time=30.01nsec ESD_current=29.43 A 40 m7 m8 20 m8 time=60.01nsec ESD_current=15.18 A 0 0 20 40 60 80 100 120 time, nsec Figure 15 140 160 180 200 ESD_Pulse .vsd ESD test pulse according to system level specification IEC61000-4-2 – Contact Discharge 15kV Some examples of RF applications addressed by the Infineon ESD protection proposal are given below: • • • • • • • FM Radio (76 MHz -110 MHz) Portable TV (170 - 220, 470 - 860 MHz) WLAN 802.11b/g/n (2.4 GHz, Tx ~ +20 dBm) Bluetooth (2.4 GHz, Tx ~ +20 dBm) Automatic Meter Reading, AMR (900 MHz, TX ~ +20 dBm) Remote Keyless Entry, RKE (315 MHz - 434 MHz - 868 MHz - 915 MHz, Tx~13 dBm) GPS (1575 MHz, Rx only but can be affected by RF interferer) For an ESD protection device tailored for medium power RF signals (=< +20 dBm), following requirements are essential: 1. RF requirements a) Bidirectional characteristic to handle DC free signals without clipping / signal distortion b) A highly symmetrical behavior of the ESD device for positive and negative voltage swings is mandatory to keep the power level of even Harmonics low c) Breakdown voltage of 5 V-10V, to avoid signal distortion at high RF voltage swing applied at the TVS diode, located close to the antenna d) High linearity e) Low leakage current and stable diode capacitance vs. RF voltage swing f) Ultra low diode capacitance is mandatory 2. ESD requirements: Application Note AN221 16 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 Appendix 1: ESD protection circuit for system level ESD robustness a) Lowest dynamic resistance Rdyn to offer best protection for the RFIC; Rdyn is characterized by Transmission Line Pulse (TLP) measurement b) Very fast switch-on time (<<1nsec) to ground the initial peak of an ESD strike according to IEC61000-4-2 c) No performance degradation over a large number of ESD zaps (>1000 Two-step ESD Protection approach General structure for a 2-step ESD approach according to Figure 16 enables to split the entire ESD current between the internal and external ESD protection device. The external device is much more robust and handles the majority of the ESD current. To avoid any impact on the RF behavior of the system and to minimize non linearity effects, the TVS diode should possess an ultra low device capacitance. Therefore the bi-directional (symmetrical) Infineon TVS Diode ESD0P2RF is well suited, which provides a diode capacitance as low as 0.2 pF and a Rdyn of only 1 Ohm. ESD robustness can be improved one step more by adding a small serial resistor between the external TVS diode and the RF amplifier input. A resistor of ~2.2 Ohm is a good compromise between additional ESD performance and insertion loss. The TVS diode ESD0P2RF in combination with the 2.2 Ohm ESD resistor would incur less than 0.23dB insertion loss up to 3 GHz. + Vcc Figure 16 PCB line or Resistor ESD current Main ESD current Internal ESD protection External ESD Pprotection U_clamp extern LNA/ Switch/ Filter V_Clamp Internal OUT Residual ESD current ESD strike PCB- line ESD_protection_1.vsd Smart 2-step ESD protection approach based on external and internal ESD protection structure For further ESD improvement it is highly recommend to add a serial capacitor (C1). The capacitor cuts off most of the high energy created by the ESD strike. For better ESD robustness, C1 should be as small as possible, but has to match to the intended application frequency as well. For a broadband ESD protection (80MHz…3GHz) C1 should be about 100pF…150pF. Optional matching can be implemented with a serial inductor L1 for a dedicated frequency. In combination with L1, C1 can be reduced significantly which improves the ESD performance. + Vcc Internal ESD Protection RX antenna RF IC input C1 optional L1 ESD Diode OUT LNA/ Switch/ Filter ESD_ resistor ESD_protection_2.vsd Figure 17 Standard ESD protection with optional ESD resistor, blocking capacitor and a serial inductor Application Note AN221 17 Revision 1.0, 2010-06-21 Low Cost DVB-T/H Television LNA BFR380L3 References References [1] BFR380L3 Datasheet, Infineon Technologies AG. Authors 1. 2. 3. 4. Ralph Kuhn, Senior Staff Application Engineer of the Business Unit “RF and Protection Devices” K.H. Lee, Infineon Korea Thomas Hieble,Verification Engineer of Business Unit “Wireless Solutions” Alexander Glas,Senior Staff Application Engineer of the Business Unit “RF and Protection Devices” Application Note AN221 18 Revision 1.0, 2010-06-21 w w w . i n f i n e o n . c o m Published by Infineon Technologies AG AN1221