BF R84 0L3 RH E SD Low P arts Co unt Lo w Nois e A mpl ifie r for 5 to 6 G Hz W LA N with BF R84 0L3 RH E SD u s ing 0 201 S M Ds Applic atio n N ote A N 281 Revision: Rev. 1.0 2012-03-16 RF and P r otecti on D evic es Edition 2012-03-16 Published by Infineon Technologies AG 81726 Munich, Germany © 2012 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. BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Application Note AN281 Revision History: 2012-03-16 Previous Revision: No previous revision Page Subjects (major changes since last revision) Trademarks of Infineon Technologies AG AURIX™, C166™, CanPAK™, CIPOS™, CIPURSE™, EconoPACK™, CoolMOS™, CoolSET™, CORECONTROL™, CROSSAVE™, DAVE™, DI-POL™, EasyPIM™, EconoBRIDGE™, EconoDUAL™, EconoPIM™, EconoPACK™, EiceDRIVER™, eupec™, FCOS™, HITFET™, HybridPACK™, I²RF™, ISOFACE™, IsoPACK™, MIPAQ™, ModSTACK™, my-d™, NovalithIC™, OptiMOS™, ORIGA™, POWERCODE™, PRIMARION™, PrimePACK™, PrimeSTACK™, PRO-SIL™, PROFET™, RASIC™, ReverSave™, SatRIC™, SIEGET™, SINDRION™, SIPMOS™, SmartLEWIS™, SOLID FLASH™, 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. 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. 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™ Openwave Systems Inc. RED HAT™ Red Hat, Inc. RFMD™ 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 Limited. Last Trademarks Update 2011-11-11 Application Note AN281, Rev. 1.0 3 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs List of Content, Figures and Tables Table of Content 1 1.1 1.2 Introduction ........................................................................................................................................ 5 ® Wi-Fi ................................................................................................................................................... 5 Device Overview: BFR840L3RHESD .................................................................................................. 6 2 Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs .......................................................................................................................................... 7 3 Overview ............................................................................................................................................. 8 4 Summary of Measurement Results .................................................................................................. 8 5 Schematics ......................................................................................................................................... 9 6 Measured Graphs ............................................................................................................................. 10 7 Evaluation Board and Layout Information .................................................................................... 17 8 Authors .............................................................................................................................................. 19 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 ® 5 – 6 GHz Wi-Fi Wireless LAN (WLAN, IEEE802.11a/n) and WiMAX (IEEE802.16e) Front-End ..... 5 Schematic Diagram of the used Circuit ................................................................................................ 9 Insertion Power Gain of the 5-6GHz WLAN LNA with BFR840L3RHESD ........................................ 10 Wideband Insertion Power Gain of the 5-6GHz WLAN LNA with BFR840L3RHESD ....................... 10 Noise figure of BFR840L3RHESD for 5100-5900 MHz ..................................................................... 11 Reverse Isolation of the 5-6GHz WLAN LNA with BFR840L3RHESD .............................................. 11 Input Matching of the 5-6GHz WLAN LNA with BFR840L3RHESD .................................................. 12 Input Matching of the 5-6GHz WLAN LNA with BFR840L3RHESD (Smith Chart) ............................ 12 Output Matching of the 5-6GHz WLAN LNA with BFR840L3RHESD ............................................... 13 Output Matching of the 5-6GHz WLAN LNA with BFR840L3RHESD (Smith Chart) ......................... 13 Wideband Stability K Factor of the 5-6GHz WLAN LNA with BFR840L3RHESD ............................. 14 Wideband Stability Mu Factor of the 5-6GHz WLAN LNA with BFR840L3RHESD ........................... 14 Input 1dB compression point of the BFR840L3RHESD circuit at 5500 MHz..................................... 15 rd Output 3 Order Intercept Point of BFR840L3RHESD at 5500 MHz ................................................ 15 OFF-Mode (Vcc = 0V, Icc = 0mA) S21 of the 5-6GHz WLAN LNA with BFR840L3RHESD ............. 16 Photo Picture of Evaluation Board for the 5-6GHz WLAN LNA with BFR840L3RHESD .................. 17 Zoom-In of Photo Picture of Evaluation Board the 5-6GHz WLAN LNA with BFR840L3RHESD ..... 17 Layout Proposal for RF Grounding of the 5-6GHz WLAN LNA with BFR840L3RHESD ................... 18 PCB Layer Information ....................................................................................................................... 18 List of Tables Table 1 Table 2 Summary of Measurement Results ...................................................................................................... 8 Bill-of-Materials..................................................................................................................................... 9 Application Note AN281, Rev. 1.0 4 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Introduction 1 Introduction 1.1 Wi-Fi® The Wi-Fi® function is one of the most important connectivity functions in Access Point (AP) routers, notebooks, smart phones and tablet PCs. Wi-Fi® according to IEEE 802.11b/g at 2.4 GHz has been widely implemented over years. Due to the cloudy WLAN network at 2.4 GHz, the Wi-Fi® applications also at 5 – 6 GHz according to IEEE 802.11n and IEEE 802.11ac are gaining focus. Also, different applications like home entertainment with wireless high-quality multimedia signal transmission, home networking notebooks, mass data storages and printers implement 5 – 6 GHz Wi-Fi® into their system to offer high-speed wireless connection. For this kind of high-speed high data rate wireless communication standards it is essential to ensure the quality of the link path. Major performance criteria of these equipments have to be fulfilled: sensitivity, strong signal capability and interference immunity. Below a general application diagram of a WLAN system is shown. WLAN/WiMAX: 4.9 – 5.9 GHz BPF LNA SPDT Switch Power Detector BPF PA WLAN/ WiMAX Transceiver IC ESD Diode Figure 1 ® 5 – 6 GHz Wi-Fi Wireless LAN (WLAN, IEEE802.11a/n) and WiMAX (IEEE802.16e) Front-End In order to increase the system sensitivity an excellent low noise amplifier (LNA) in front of the receiver is mandatory, especially in an environment with very weak signal strength and because of the insertion loss of the SPDT switch and the Bandpass Filter (BPF) or diplexer. Application Note AN281, Rev. 1.0 5 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Introduction The typical allowed overall system Noise Figure (NF) of the receiver chain of approx. 2 dB can only be achieved by using a high-gain low noise amplifier. As an example, to increase the sensitivity by 5 dB means doubled link distance. In addition, strong signal environment can exist when the equipment is next to a transmitter. In that case, the LNA must be linear enough, i.e. have high 1dB compression point. This avoids saturation, degradation of the gain and increased noise figure. The cloudy wireless environment nowadays makes the wireless system design more complicated. All kinds of interference might introduce signal distortion and reduce the real throughput data rate. To ensure that the low noise amplifier is not interfered by those signals good linearity characteristics like high IP3 are required. This application note is focusing on the LNA block, but Infineon does also support with RFswitches, TVS-diodes for ESD protection and RF Schottky diodes for power detection. 1.2 Device Overview: BFR840L3RHESD The high end ultra low noise SiGe:C Heterojunction Bipolar RF Transistor (HBT) BFR840L3RHESD has been developed using Infineon’s latest B9HFM technology. This technology has been specifically designed for WiFi applications between 5 and 6 GHz. The BFR840L3RHESD is available in the extremely small and leadless TSLP-3-9 package (0.31mm height) and is especially suitable for portable battery-powered applications in which reduced power consumption and small size is a key requirement. The key features of this technology are very high transition frequency (fT = 80 GHz) and low parasitics, which enable to achieve higher gain and lower noise figure compared to the previous generation SiGe:C RF transistor BFR740L3RH. On top of that the BFR840L3RHESD has an integrated 1.5kV HBM ESD protection which makes the device robust against electrostatic discharge and extreme RF input power. Moreover the Gamma Opt point (location of optimum source impedance for minimum noise figure) at 5 to 6 GHz is located close to 50 Ohm which enables to achieve input matching without any external matching component. BFR840L3RHESD is also available in other packages, e.g. BFP840ESD (SOT343), BFP840FESD (TSFP-4-1). Application Note AN281, Rev. 1.0 6 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs 2 Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs This application note presents the measurement results of the Low Noise Amplifier using BFR840L3RHESD SiGe:C Heterojunction Bipolar RF transistor from Infineon Technologies for 5100 MHz to 5900 MHz WLAN applications. The circuit schematic shown in Figure 2 doesn’t require any external input matching element. Nevertheless, proper RF grounding on PCB has to be ensured (please refer to Figure 18) in order to achieve the good performance. It’s a low parts count solution which requires only 8 passive 0201 SMD components. The LNA brings gain from 15.5 dB to 14.7 dB over the frequency band from 5100 MHz to 5900 MHz. The gain is approx. 1 dB higher compare to BFR740L3RH 5 – 6 GHZ WLAN LNA (AN170). Since there is no external passive required for matching at the input which is also better for noise figure, we have achieved noise figure as low as 0.92 dB (SMA and PCB losses are subtracted), which is 0.2 dB lower compare to BFR740L3RH 5 – 6 GHZ WLAN LNA (AN170). Furthermore, this device provides an unconditional stability from 10 MHz to 11 GHz. The circuit is matched at input and output, and presents an input return loss more than 10 dB, and an output return loss more than 12 dB. Moreover, the LNA consumes 3.5mA less current compare to BFR740L3RH 5 – 6 GHZ WLAN LNA (AN170). At the frequency of 5.5 GHz, using two tones spaced of 1 MHz, the output third intercept point reaches 17 dBm. Besides, we obtain 1dB compression point of -8 dBm at the input at 5.5 GHz. Application Note AN281, Rev. 1.0 7 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Overview 3 Overview Device: BFR840L3RHESD Application: Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs PCB Marking: BFR840L3RHESD TSLP-3-9 M120131 (PCB designed for 0201 SMDs) 4 Summary of Measurement Results Table 1 Summary of Measurement Results Parameter Symbol Value Unit DC Voltage Vcc 3.0 V DC Current Icc 9.4 mA Frequency Range Freq 5100 5500 5900 MHz Gain G 15.5 15.1 14.7 dB Noise Figure NF 0.98 0.96 0.92 dB RLin 10 11 13 dB RLout 12 13 14 dB IRev 22 21 20 dB Input Return Loss Output Return Loss Reverse Isolation Input P1dB IP1dB -8 dBm Output P1dB OP1dB +6 dBm Input IP3 IIP3 +2 dBm Output IP3 OIP3 +17 dBm k >1.0 -- Stability Application Note AN281, Rev. 1.0 8 / 20 Note/Test Condition SMA and PCB losses (0.14 dB) are subtracted Power @ Input: -25 dBm f1= 5500 MHz, f2= 5501 MHz Stability measured from 10MHz to 11GHz 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Schematics 5 Schematics Vcc= 3.0 V J3 DC Connector All passives are “0201“ case size Inductor L1 LQP30T Series Capacitors GRM Series I = 9.4 mA R3 120 ohms R0 0 Ohm R2 27 ohms C3 1pF R1 33k Ohms L1 3.7nH Q1 BFR840L3RHESD C1 22pF J1 RF Port1 INPUT C4 1nF A proper RF grounding is required to ensure the LNA performance. Please refer to Chapter 7 for the layout proposal. Table 2 Symbol J2 RF Port2 OUTPUT Total Component Count = 9 including BFR840L3RHESD transistor PCB = M120131 BFR840L3RHESD PCB Board Material = Standard FR4 Layer spacing (top RF to internal ground plane): 0.2 mm Figure 2 C2 18pF Inductors = 1 (Low Q) Resistors = 3 Capacitors = 4 Schematic Diagram of the used Circuit Bill-of-Materials Value Unit Size Manufacturer Comment C1 22 pF 0201 Murata GRM0335 series Input DC block C2 18 pF 0201 Murata GRM0335 series Output DC block C3 1 pF 0201 Murata GRM0335 series Output matching C4 1 nF 0201 Murata GRM0335 series L1 3.7 nH 0201 Murata LQP30T series R0 0 Ω 0201 Various RF decoupling / blocking cap Output matching and biasing to the Collector Jumper R1 33 kΩ 0201 Various DC biasing R2 27 Ω 0201 Various Stability improvement R3 120 Ω 0201 Various DC biasing (provies DC negative feedback to stabilize DC operating point over temperature variation, transistor hFE variation, etc.) BFR840L3RHESD SiGe:C Heterojunction Bipolar RF Transistor Q1 Application Note AN281, Rev. 1.0 TSLP-3-9 Infineon Technologies 9 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Measured Graphs 6 Measured Graphs Insertion Power Gain InBand 17 16 5900 MHz 14.7 dB 15 5100 MHz 15.5 dB 14 13 4000 Figure 3 4500 5000 5500 6000 Frequency (MHz) 6500 7000 Insertion Power Gain of the 5-6GHz WLAN LNA with BFR840L3RHESD Insertion Power Gain WideBand 20 18 5100 MHz 15.5 dB 5900 MHz 14.7 dB 16 14 12 10 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 Frequency (MHz) Figure 4 Wideband Insertion Power Gain of the 5-6GHz WLAN LNA with BFR840L3RHESD Application Note AN281, Rev. 1.0 10 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Measured Graphs Noise Figure 1.5 NF(dB) 1.3 1.1 5100 MHz 0.98 dB 5900 MHz 0.92 dB 0.9 0.7 5000 Figure 5 5200 5400 5600 Frequency (MHz) 5800 6000 Noise figure of BFR840L3RHESD for 5100-5900 MHz Reverse Isolation 60 50 40 5100 MHz 21.8 dB 5900 MHz 20.3 dB 30 20 10 0 4000 Figure 6 4500 5000 5500 6000 Frequency (MHz) 6500 7000 Reverse Isolation of the 5-6GHz WLAN LNA with BFR840L3RHESD Application Note AN281, Rev. 1.0 11 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Measured Graphs Input Matching -6 -8 -10 5100 MHz -10.5 dB -12 -14 4000 Figure 7 4500 5900 MHz -13.7 dB 5000 5500 6000 Frequency (MHz) 6500 7000 Input Matching of the 5-6GHz WLAN LNA with BFR840L3RHESD Swp Max 7000MHz 2. 0 6 0. 0.8 1.0 Input Matching Smith 0. 4 0 3. 0 4. 5.0 5100 MHz r 0.579723 x -0.267834 -4 .0 -5. 0 2 -0. -3 .0 .0 -2 -1.0 -0.8 -0 .6 .4 -0 Figure 8 5.0 4.0 2.0 1.0 0.8 0.6 0.4 0.2 3.0 -10.0 0 10.0 10.0 0.2 5900 MHz r 0.641942 x -0.0162867 Swp Min 3500MHz Input Matching of the 5-6GHz WLAN LNA with BFR840L3RHESD (Smith Chart) Application Note AN281, Rev. 1.0 12 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Measured Graphs Output Matching -10 -12 5100 MHz -12.13 dB -14 5900 MHz -14.95 dB -16 -18 4000 Figure 9 4500 5000 5500 6000 Frequency (MHz) 6500 7000 Output Matching of the 5-6GHz WLAN LNA with BFR840L3RHESD Swp Max 7000MHz 2. 0 6 0. 0.8 1.0 Output Matching Smith 0. 4 0 3. 0 4. 10.0 5.0 4.0 3.0 10.0 2.0 1.0 0.8 0.6 0.4 0.2 0.2 0 5.0 5900 MHz r 0.832929 x -0.308556 -10.0 2 -0. .0 -2 -1.0 -0.8 -0 .6 -3 .0 .4 -0 Figure 10 4 .0 -5. 0 5100 MHz r 0.998797 x -0.529221 Swp Min 3500MHz Output Matching of the 5-6GHz WLAN LNA with BFR840L3RHESD (Smith Chart) Application Note AN281, Rev. 1.0 13 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Measured Graphs Stability K Factor 3 2 1 1615 MHz 1.06 0 10 Figure 11 2010 4010 6010 Frequency (MHz) 8010 10000 Wideband Stability K Factor of the 5-6GHz WLAN LNA with BFR840L3RHESD Stability Mu Factor 2 1.5 1 1620.9 MHz 1.015 Mu2 factor 0.5 Mu1 factor 0 10 Figure 12 2010 4010 6010 Frequency (MHz) 8010 10000 Wideband Stability Mu Factor of the 5-6GHz WLAN LNA with BFR840L3RHESD Application Note AN281, Rev. 1.0 14 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Measured Graphs Input 1dB Compression Point 20 Gain(dB) 15 -26.81 dBm 15.12 dB -7.915 dBm 14.12 dB 10 5 0 -27 -22 -17 -12 Pin (dBm) -7 -2 Figure 13 Input 1dB compression point of the BFR840L3RHESD circuit at 5500 MHz Figure 14 Output 3 Order Intercept Point of BFR840L3RHESD at 5500 MHz 0 rd Application Note AN281, Rev. 1.0 15 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Measured Graphs OFF Mode S21 -19 -20 5100 MHz -19.9 dB -21 5900 MHz -20.6 dB -22 -23 -24 4000 Figure 15 4500 5000 5500 6000 Frequency (MHz) 6500 7000 OFF-Mode (Vcc = 0V, Icc = 0mA) S21 of the 5-6GHz WLAN LNA with BFR840L3RHESD Application Note AN281, Rev. 1.0 16 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Evaluation Board and Layout Information 7 Evaluation Board and Layout Information Figure 16 Photo Picture of Evaluation Board for the 5-6GHz WLAN LNA with BFR840L3RHESD Figure 17 Zoom-In of Photo Picture of Evaluation Board the 5-6GHz WLAN LNA with BFR840L3RHESD Application Note AN281, Rev. 1.0 17 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Evaluation Board and Layout Information Figure 18 Layout Proposal for RF Grounding of the 5-6GHz WLAN LNA with BFR840L3RHESD Vias FR4 Core, 0.2mm Copper 35µm Figure 19 FR4 Prepreg, 0.8mm PCB Layer Information Application Note AN281, Rev. 1.0 18 / 20 2012-03-16 BFR840L3RHESD Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFR840L3RHESD using 0201 SMDs Authors 8 Authors Shamsuddin Ahmed, Application Engineer of Business Unit “RF and Protection Devices” Dr. Chih-I Lin, Senior Staff Engineer of Technical Marketing of Business Unit “RF and Protection Devices” Application Note AN281, Rev. 1.0 19 / 20 2012-03-16 w w w . i n f i n e o n . c o m Published by Infineon Technologies AG AN281