BF P840 F ES D Low N oise A mpli fier for 5 to 6 G Hz WLA N usi ng BFP 84 0FE S D wi th Lo w Par ts - Cou nt Applic atio n N ote A N 289 Revision: Rev. 2.0 2012-11-09 RF and P r otecti on D evic es Edition 2012-11-09 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). 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BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Application Note AN289 Revision History: 2012-11-09 Previous Revision: Rev 1.0 Page Subjects (major changes since last revision) 8, 10 – 16 Update of the measurement results 9 Update of the circuit and bill of materials 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. 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Last Trademarks Update 2011-11-11 Application Note AN289, Rev. 2.0 3 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count List of Content, Figures and Tables Table of Content 1 1.1 1.2 Introduction ........................................................................................................................................ 5 ® Wi-Fi ................................................................................................................................................... 5 Device Overview: BFP840FESD .......................................................................................................... 6 2 Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFP840FESD ........................ 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 9 Remark .............................................................................................................................................. 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 5-6 GHz WLAN LNA with BFP840FESD .............................................. 10 Wideband Insertion Power Gain of the 5-6 GHz WLAN LNA with BFP840FESD ............................. 10 Noise Figure of BFP840FESD LNA for 5100 - 5900 MHz ................................................................. 11 Reverse Isolation of the 5-6 GHz WLAN LNA with BFP840FESD .................................................... 11 Input Matching of the 5-6 GHz WLAN LNA with BFP840FESD ........................................................ 12 Input Matching of the 5-6 GHz WLAN LNA with BFP840FESD (Smith Chart) .................................. 12 Output Matching of the 5-6 GHz WLAN LNA with BFP840FESD ...................................................... 13 Output Matching of the 5-6 GHz WLAN LNA with BFP840FESD (Smith Chart) ............................... 13 Wideband Stability k Factor of the 5-6 GHz WLAN LNA with BFP840FESD .................................... 14 Wideband Stability Mu Factor of the 5-6 GHz WLAN LNA with BFP840FESD ................................. 14 Input 1dB Compression Point of the BFP840FESD Circuit at 5500 MHz .......................................... 15 rd Output 3 Order Intercept Point of BFP840FESD at 5500 MHz ........................................................ 15 OFF-Mode (Vcc = 0V, Icc = 0mA) S21 of the 5-6 GHz WLAN LNA with BFP840FESD ................... 16 Photo of the BFP840FESD 5-6 GHz WLAN LNA Evaluation Board .................................................. 17 Zoom-In Picture of the BFP840FESD 5-6 GHz WLAN LNA Evaluation Board ................................. 17 Layout Proposal for RF Grounding of the 5-6 GHz WLAN LNA with BFP840FESD ......................... 18 PCB Layer Information ....................................................................................................................... 18 List of Tables Table 1 Table 2 Summary of Measurement Results ...................................................................................................... 8 Bill-of-Materials..................................................................................................................................... 9 Application Note AN289, Rev. 2.0 4 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Introduction 1 Introduction 1.1 Wi-Fi® Wireless Fidelity (Wi-Fi®) plays a major role in today’s communications by enabling constant connection in the 2.4 GHz and 5 GHz bands and broadband Internet access for users with laptops or devices equipped with wireless network interface while roaming within the range of fixed access points (AP) or a public hotspot. 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 connectivity. When wider coverage areas are needed and especially when a higher order modulation scheme is used such as in emerging very high throughput wireless specifications like 256 Quadrature Amplitude Modulation (256-QAM) in IEEE 802.11ac, the SNR requirements for both the AP and the client are more stringent. 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 Application Note AN289, Rev. 2.0 5 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Introduction 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. The typical allowed receiver chain Noise Figure (NF) of approx. 2 dB can only be achieved by using a high-gain low noise amplifier. 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. 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: BFP840FESD The BFP840FESD is a discrete hetero-junction bipolar transistor (HBT) specifically designed for high performance 5 GHz band low noise amplifier (LNA) solutions for Wi-Fi connectivity applications. It combines the 80 GHz fT silicon-germanium:carbide (SiGe:C) B9HFM process with special device geometry engineering to reduce the parasitic capacitance between substrate and transistor that degrades high-frequency characteristics, resulting in an inherent input matching and a major improvement in power gain 5 GHz band together with a low noise figure performance that is industry's best. The BFP840FESD has an integrated 1.5kV HBM ESD protection which makes the device robust against electrostatic discharge and extreme RF input power. The device offers its high performance at low current and voltage and is especially well-suited for portable battery powered applications in which energy efficiency is a key requirement. The BFP840FESD is housed in flat-leads TSFP-4-1 package. Further variants are available in industry standard visible-leads SOT343 package (BFP840ESD) and in the low-height 0.31mm TSLP-3-9 package (BFR840L3RHESD) specially fitting into modules. Application Note AN289, Rev. 2.0 6 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFP840FESD 2 Low Parts Count Low Noise Amplifier for 5 to 6 GHz WLAN with BFP840FESD This application note presents the measurement results of the Low Noise Amplifier using BFP840FESD for 5100 MHz to 5900 MHz WLAN applications. The circuit schematic shown in Figure 2 doesn’t require any external input matching elements. It’s a low parts count solution which requires only 8 passive 0402 SMD components and brings gain from 18.4 dB to 17.4 dB over the frequency band. The gain is approx. 2 dB higher compared to BFP740F (AN168). The noise figure varies from 1.05 dB to 1.0 dB (SMA and PCB losses are subtracted) over the frequency band. The circuit achieves an input and output return loss of 10 dB. Furthermore, the circuit is unconditionally stable from 10 MHz to 15 GHz. However, Proper RF grounding on PCB has to be ensured in order to achieve stability k-factor > 1 above 11 GHz (Figure 18). At 5.5 GHz, using two tones spacing of 1 MHz, the output third intercept point OIP3 reaches 15.3 dBm. Besides, we obtain 1dB input compression point IP1dB of -11.5 dBm. Application Note AN289, Rev. 2.0 7 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Overview 3 Overview Device: BFP840FESD Application: Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count PCB Marking: BFP840FESD TSFP-4 M12051302 4 Summary of Measurement Results Table 1 Summary of Measurement Results Parameter Symbol Value Unit DC Voltage Vcc 3.0 V DC Current Icc 14 mA Frequency Range Freq 5100 5500 5900 MHz Gain G 18.9 18.3 17.7 dB Noise Figure NF 1.05 1.05 1.08 dB RLin 11.1 11.6 10.8 dB RLout 11.4 10.6 11.7 dB IRev 26.5 26.2 25.9 dB Input Return Loss Output Return Loss Reverse Isolation Input P1dB IP1dB -9.9 dBm Output P1dB OP1dB +7.4 dBm Input IP3 IIP3 -0.7 dBm Output IP3 OIP3 +17.6 dBm k > 1.0 -- Stability Application Note AN289, Rev. 2.0 8 / 20 Note/Test Condition SMA and PCB losses (~0.15 dB) are subtracted Power @ Input: -25 dBm f1= 5500 MHz, f2= 5501 MHz Stability measured from 10MHz to 15GHz 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Schematics 5 Schematics Vcc= 3.0 V J3 DC Connector All passives are “0402“ case size Inductor L1 LQP15M Series Capacitors Various I = 14 mA R3 51 Ω C4 33 pF C3 1.0 pF R2 51 Ω R1 L1 1.8 nH 27 kΩ C1 22 pF J1 RF Port1 INPUT Q1 BFR840FESD 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 externals Count = 8 PCB Marking= BFP840FESD M12051302 PCB Board Material = Standard FR4 Layer spacing (top RF to internal ground plane): 0.2 mm Figure 2 C2 1.0 pF Inductors = 1 (LQP15M Series) Resistors = 3 Capacitors = 4 Schematic Diagram of the used Circuit Bill-of-Materials Value Unit Size Manufacturer Comment C1 22 pF 0402 Various Input DC block C2 1.0 pF 0402 Various Output DC block & output matching C3 1.0 pF 0402 Various Output matching C4 33 pF 0402 Various L1 1.8 nH 0402 Murata LQP15M series R1 27 kΩ 0402 Various RF decoupling / blocking cap Output matching and biasing to the Collector DC biasing R2 51 Ω 0402 Various Stability improvement R3 51 Ω 0402 Various DC biasing (provides DC negative feedback to stabilize DC operating point over temperature variation, transistor hFE variation, etc.) BFP840FESD SiGe:C Heterojunction Bipolar RF Transistor Q1 Application Note AN289, Rev. 2.0 TSFP-4-1 Infineon Technologies 9 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Measured Graphs 6 Measured Graphs Insertion Power Gain InBand 20 5100 MHz 18.9 dB 19 5500 MHz 18.3 dB 5900 MHz 17.7 dB 18 17 16 15 4000 Figure 3 4500 5000 5500 6000 Frequency (MHz) 6500 7000 Insertion Power Gain of the 5-6 GHz WLAN LNA with BFP840FESD Insertion Power Gain WideBand 20 15 2400 MHz 13.4 dB 5100 MHz 18.9 dB 5500 MHz 18.3 dB 5900 MHz 17.7 dB 10 5 0 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 Frequency (MHz) Figure 4 Wideband Insertion Power Gain of the 5-6 GHz WLAN LNA with BFP840FESD Application Note AN289, Rev. 2.0 10 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Measured Graphs Noise Figure 1.4 1.3 NF(dB) 1.1 5900 MHz 1.08 dB 5500 MHz 1.05 dB 1.2 5100 MHz 1.05 dB 1 0.9 0.8 0.7 5100 Figure 5 5300 5500 Frequency (MHz) 5700 5900 Noise Figure of BFP840FESD LNA for 5100 - 5900 MHz Reverse Isolation 0 -10 5100 MHz -26.5 dB 5500 MHz -26.2 dB 5900 MHz -25.9 dB -20 -30 -40 -50 -60 4000 Figure 6 4500 5000 5500 6000 Frequency (MHz) 6500 7000 Reverse Isolation of the 5-6 GHz WLAN LNA with BFP840FESD Application Note AN289, Rev. 2.0 11 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Measured Graphs Input Matching -2 -4 -6 5100 MHz -11.1 dB -8 5500 MHz 5900 MHz -10.8 dB -11.6 dB -10 -12 4000 Figure 7 4500 5000 5500 6000 Frequency (MHz) 6500 7000 Input Matching of the 5-6 GHz WLAN LNA with BFP840FESD 5900 MHz r 0.765841 x 0.472862 2. 0 Swp Max 7000MHz 6 0. 0.8 1.0 Input Matching Smith 0 3. 0. 4 0 4. 5100 MHz r 0.618147 x 0.247142 5.0 0.2 10.0 5.0 4.0 3.0 5500 MHz r 0.699906 x 0.344662 2.0 1.0 0.8 0.6 0.4 0 0.2 10.0 -10.0 2 -0. -4 .0 -5. 0 -3 .0 Figure 8 .0 -2 -1.0 -0.8 -0 .6 .4 -0 Swp Min 3500MHz Input Matching of the 5-6 GHz WLAN LNA with BFP840FESD (Smith Chart) Application Note AN289, Rev. 2.0 12 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Measured Graphs Output Matching 0 -5 5500 MHz -10.6 dB 5100 MHz -11.4 dB 5900 MHz -11.7 dB -10 -15 -20 -25 -30 4000 Figure 9 4500 5000 5500 6000 Frequency (MHz) 6500 7000 Output Matching of the 5-6 GHz WLAN LNA with BFP840FESD Swp Max 7000MHz 2. 0 6 0. 0.8 1.0 Output Matching Smith 0. 4 0 3. 0 4. 5.0 10.0 5.0 4.0 3.0 2.0 1.0 0.8 0.6 0.4 0 0.2 0.2 10.0 5100 MHz r 1.15799 x -0.578139 -10.0 5500 MHz r 1.00561 x -0.619824 -1.0 -0.8 .0 -2 -0 .6 Figure 10 -3 .0 5900 MHz r 0.920867 x -0.509075 .4 -0 -4 .0 -5. 0 2 -0. Swp Min 3500MHz Output Matching of the 5-6 GHz WLAN LNA with BFP840FESD (Smith Chart) Application Note AN289, Rev. 2.0 13 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Measured Graphs Stability k Factor 3 2 5100 MHz 1.2 1 5900 MHz 1.2 5500 MHz 1.2 0 10 5010 10010 15000 Frequency (MHz) Figure 11 Wideband Stability k Factor of the 5-6 GHz WLAN LNA with BFP840FESD Stability Mu Factor 2 1.5 1 Mu2 factor 0.5 Mu1 factor 0 10 5010 10010 15000 Frequency (MHz) Figure 12 Wideband Stability Mu Factor of the 5-6 GHz WLAN LNA with BFP840FESD Application Note AN289, Rev. 2.0 14 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Measured Graphs Input 1dB Compression Point 20 Gain(dB) 15 -30 dBm 18.34 dB -9.905 dBm 17.34 dB 10 5 0 -30 Figure 13 -25 -20 -15 Pin (dBm) -10 -5 0 Input 1dB Compression Point of the BFP840FESD Circuit at 5500 MHz Output 3rd Order Intercept Point 0 5501 MHz -6.83 Power (dBm) -20 5499 MHz -55.6 -40 -60 -80 -100 5498.5 Figure 14 5499.5 5500.5 Frequency (MHz) 5501.5 5502.5 rd Output 3 Order Intercept Point of BFP840FESD at 5500 MHz Application Note AN289, Rev. 2.0 15 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Measured Graphs OFF Mode S21 -20 -22 5100 MHz -21.3 dB 5900 MHz -20.6 dB -24 -26 -28 -30 4000 Figure 15 4500 5000 5500 6000 Frequency (MHz) 6500 7000 OFF-Mode (Vcc = 0V, Icc = 0mA) S21 of the 5-6 GHz WLAN LNA with BFP840FESD Application Note AN289, Rev. 2.0 16 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Evaluation Board and Layout Information 7 Evaluation Board and Layout Information Figure 16 Photo of the BFP840FESD 5-6 GHz WLAN LNA Evaluation Board Figure 17 Zoom-In Picture of the BFP840FESD 5-6 GHz WLAN LNA Evaluation Board Application Note AN289, Rev. 2.0 17 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Evaluation Board and Layout Information 0.2mm B E BFP840FESD C E 0.3mm Figure 18 Layout Proposal for RF Grounding of the 5-6 GHz WLAN LNA with BFP840FESD Vias FR4 Core, 0.2mm Copper 35µm Figure 19 FR4 Prepreg, 0.8mm PCB Layer Information Application Note AN289, Rev. 2.0 18 / 20 2012-11-09 BFP840FESD Low Noise Amplifier for 5 to 6 GHz WLAN with Low Parts-Count Authors 8 Authors Shamsuddin Ahmed, Application Engineer of Business Unit “RF and Protection Devices” Dr. Chih-I Lin, Senior Staff Engineer/Technical Marketing RF of Business Unit “RF and Protection Devices” 9 Remark The graphs are generated with the simulation program AWR Microwave Office®. Application Note AN289, Rev. 2.0 19 / 20 2012-11-09 w w w . i n f i n e o n . c o m Published by Infineon Technologies AG AN289