A p p l i c a t i o n N o t e , R e v . 2 . 2 , J u l y 2 01 0 A p p li c a t i o n N o t e N o . 1 7 7 M i n i a tu r e E S D r o b u s t L o w N o i s e A m p l i fi e r ( L N A ) f o r e m b e d de d F M R a d i o A n t e nn a i n H a nd s e t s u s i n g B G B 70 7 L 7 E S D an d E S D 0 P 8 R F L R F & P r o t e c ti o n D e v i c e s Edition 2010-07-07 Published by Infineon Technologies AG 81726 München, Germany © Infineon Technologies AG 2010. 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. 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) WITH RESPECT TO ANY AND ALL INFORMATION GIVEN IN THIS APPLICATION NOTE. ACTIVVTM IS A REGISTERED TRADEMARK OF LAIRD TECHNOLOGIES AND THE ACTIVV TM FM RADIO ANTENNA SYSTEM IS COVERED BY INTELLECTUALLY PROPERTY RIGHTS OWNED AN MAINTAINED BY LAIRD TECHNOLOGIES. Information For further information on technology, delivery terms and conditions and prices please contact your nearest Infineon Technologies Office (www.infineon.com). For further information on ActivvTM FM radio antenna system, antenna offerings, license conditions and prices please contact your nearest Laird Technologies Office (www.lairdtech.com). Warnings Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Infineon Technologies Office. Infineon Technologies Components may only be used in life-support devices or systems 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. Application Note No. 177 Application Note No. 177 Revision History: 2010-07-07, Rev. 2.2 Previous Version: 2009-07-31, Rev. 2.1 Page Subjects (major changes since last revision) 6 figure2 pin out names of BGB707 updated Application Note 3 Rev. 2.2, 2010-07-07 Application Note No. 177 Introduction 1 Introduction FM Radio has a long history to its credit starting from its development in 1933. Today, FM radio is an integral part of almost all mobile phones. In a common mobile phone, the headset cable serves as antenna for FM reception, wherein the antenna size (~75 cm) is a bit relaxed. There is a clear market trend to be able to use FM radio also without the headset cable. The antenna needs then to be integrated inside the phone. But in this case, the space constraint poses a challenge on the antenna design. Shrinking the size of the antenna introduces a high loss in the system which deteriorates the receiver performance, namely the receiver sensitivity. Infineon’s latest generation low noise amplifier (LNA) BGB707L7ESD is able to solve this problem by enhancing the receiver sensitivity. Using it in a hand held device also demands low current consumption, power-off function and high linearity due to the co-existence of cellular bands.The LNA is designed for worldwide FM band (76108 MHz) and high ESD robustness at the RF-in port, which supports outstanding ESD robustness on system level. Infineon offers its LNA solution BGB707L7ESD, which fulfills all these performance criteria in a very small and leadless package TSLP-7-1 (2.0 x 1.3 x 0.4 mm). A further highlight of the BGB707L7EDS is an integrated active biasing which enables consistent operation with varying temperature and process variations. It finds its application in all kinds of mobile devices like mobile phones, PDAs, portable FM radio, MP3 players etc. Putting Infineon’s ESD protection diode ESD0P8RFL in front of the LNA improves the system’s ESD performance up to 8 kV contact discharge (IEC61000-4-2) at RF input. The diode is mounted in the small leadless TSLP-4-7 package (1.2 x 0.8 x 0.39 mm) and has a parasitic capacitance of only 0.8 pF. With this application proposal Infineon offers a perfect solution for a ESD robust LNA for embedded FM radio antennas in handsets (e.g. Laird Technologies ActivvTM antenna system). The design is suited for miniature and slim handset design due to the small form factor of the TSLP packages. The LNA fits easily into a 8mm x 8mm sized area when using 0201 capacitors and resistors as shown in the figure below on the right hand side. Figure 1 Pictures of standard evaluation board (left) and miniature board (right). Please note that the pictures use different scales Application Note 4 Rev. 2.2, 2010-07-07 Application Note No. 177 Performance Overview 2 Performance Overview The following table gives a quick overview on the performance of the FM Antenna LNA described in this application note. Table 1 Electrical characteristics at TA = 25°C, VCC = 3.0V, VCTRL = 3.0 V, ICCq = 3.0 mA, f = 100MHz Parameter Symbol Values Min. |S21| Typ. 2 Unit Max. 12.0 dB RLIN RLOUT F50ohm 0.5 dB 16 dB 1.0 dB Input 1dB gain compression point P-1dB -5.5 dBm Input 3rd Order Intercept Point3) IIP3 -12.5 dBm Quiescent supply current ICCq 3.0 mA ESD protection level- RF input4) RFinputESD +/-8 kV Insertion power gain 1) Input return loss Output return loss Noise figure (Zs=50Ohm) 2) 1) LNA presents a high input impedance match over the 76-108 MHz FM radio band. See fig. 6 2) Noise figure measurement at 100 MHz is jammed by FM radio signals, which increase measurement result by appr. 0.4 dB. Above result can be achieved by usage of an aggressive low pass filter and a PCB with short lines 3) IP3 value depends on termination of all intermodulation frequency components. Termination used for the measurement is 50 Ω from 0.1 to 6 GHz 4) Measured according IEC61000-4-2 contact discharge. Replacing R1 0 Ω link with an inductor increases ESD protection level. E.g. a 3.3 nH 0402 inductor increases ESD protection level to +/-10 kV typical. Application Note 5 Rev. 2.2, 2010-07-07 Application Note No. 177 Application Circuit 3 Application Circuit In this section, the application circuit for the BGB707L7ESD is described. The circuit requires minimal usage of external SMD components due to the integration of the biasing circuit which saves PCB space and therefore cost. The application schematic is shown in Figure 2 and the function of each component is explained in Table 2. DC, Vcc BGB707 L7ESD Internal Biasing VCC R1 L1 5 R3 VCtrl VBias 3 4 LNA ESD1 R4 C5 RFOut RFIn C1 DC, VPD Adj 2 C2 C4 6 1 C3 R2 7 In (on pack age back side ) schematic_diagram .vsd Figure 2 Application schematic for FM Radio Table 2 Bill of material Out Component Value Manufacturer/Type Function C1 Varies with antenna impedance (N.C. in AN) Various / 0402 Impedance matching C2 330 pF Various / 0402 DC blocking C3 47 nF Various / 0402 DC stabilization C4 47 nF Various / 0402 DC stabilization C5 330 pF Various / 0402 DC blocking R1 0Ω Various / 0402 Optional: can be replaced by an Inductor to enhance the ESD robustness R2 12 kΩ Various / 0402 To set supply current to 3 mA R3 56 Ω Various / 0402 Stability R4 10 Ω Various / 0402 Stability L1 470 nH Taiyo Yuden LK1608R47K-T / 0603 RF choke, value and size important for stability ESD1 ESD0P8RFL Infineon / TSLP-4-7 Application Note 6 ESD protection diode to support 8 kV contact discharge (IEC60001-4-2) at RF input Rev. 2.2, 2010-07-07 Application Note No. 177 Layout 4 Layout Figure 3 shows the layout and the component placement of the printed circuit board used to assemble and test the LNA. Figure 3 PCB layout Application Note 7 Rev. 2.2, 2010-07-07 Application Note No. 177 Measurement results 5 Measurement results The following graphs show measured performance of the LNA described here. Please note that all this data includes both losses of microstrip lines and SMA connectors. 5.1 Narrowband graphs Noise Figure 1,400 1,350 1,300 1,250 NF (dB) 1,200 1,150 1,100 1,050 1,000 0,950 0,900 70 75 80 85 90 95 100 105 110 Frequency (MHz) Figure 4 Noise figure with a 50 Ω termination at input and output Application Note 8 Rev. 2.2, 2010-07-07 Application Note No. 177 Measurement results Gain 15 S21 (dB) 13 11 9 7 5 0 50 100 Frequency (MHz) 150 200 N B_Gain .v s d Figure 5 Gain Input Matching 2. 0 6 0. 0.8 1.0 Swp Max 200MHz 0. 4 0 3. 76 MHz r 81.5171 Ohm x 441.387 Ohm 4. 0 5. 0 0.2 10.0 5.0 4.0 3.0 2.0 1.0 0.8 0.6 0.4 0 0.2 10 . 0 108 MHz r 2355.51 Ohm x -761.974 Ohm -1 0. 0 2 0 -4 .0 -3 .0 .0 -2 -1.0 -0.8 -0 .6 .4 -0 Figure 6 -5. -0. Swp Min 10MHz N B_ s11 .v sd Input matching Application Note 9 Rev. 2.2, 2010-07-07 Application Note No. 177 Measurement results Matching 0 -2 S11 & S22 (dB) -4 -6 -8 DB(|S(2,2)|) -10 DB(|S(1,1)|) -12 -14 -16 -18 -20 0 50 100 Frequency (MHz) 150 200 N B_ m atching.v s d Figure 7 Input and output matching S12 -30 S12 (dB) -40 -50 -60 -70 0 50 100 Frequency (MHz) 150 200 N B_s 12 .v s d Figure 8 Isolation Application Note 10 Rev. 2.2, 2010-07-07 Application Note No. 177 Measurement results 5.2 Wideband stability Stability 20 18 16 K-Factor 14 12 10 8 6 4 2 0 0 1000 2000 3000 4000 5000 6000 Frequency (MHz) 7000 8000 9000 10000 stability.vsd Figure 9 Stability Application Note 11 Rev. 2.2, 2010-07-07