A pp . Not e , V 1. 0 , No v 20 0 3 Application Note TDx5101x Low P ow er An te nna Bo ard fo r Jap ane se Market Ver s i on 1 .0 W i re l e s s C o m mu n i c a t i o n N e v e r s t o p t h i n k i n g . Edition 2003-11-26 Published by Infineon Technologies AG, St.-Martin-Strasse 53, 81669 München, Germany © Infineon Technologies AG 2004. All Rights Reserved. Attention please! The information herein is given to describe certain components and shall not be considered as a guarantee of characteristics. Terms of delivery and rights to technical change reserved. We hereby disclaim any and all warranties, including but not limited to warranties of non-infringement, regarding circuits, descriptions and charts stated herein. Information For further information on technology, delivery terms and conditions and prices please contact your nearest Infineon Technologies Office in Germany or the Infineon Technologies Companies and our Infineon Technologies Representatives worldwide (www.infineon.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. A pp . Not e , V 1. 0 , No v 20 0 3 Application Note TDx5101x Low P ow er An te nna Bo ard fo r Jap ane se Market Ver s i on 1 .0 W i re l e s s C o m mu n i c a t i o n N e v e r s t o p t h i n k i n g . Application Note TDx5101x Confidential Revision History: 2003-11-26 Previous Version: Page V 1.0 none Subjects (major changes since last revision) We Listen to Your Comments Any information within this document that you feel is wrong, unclear or missing at all? Your feedback will help us to continuously improve the quality of this document. Please send your proposal (including a reference to this document) to: [email protected] Application Note TDx5101x Table of Contents Page 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 2.1 2.2 2.3 2.4 TDK5101F Antenna-Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Measurement Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 TDx5101 Antenna-Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 4.1 4.2 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Output Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 App.Note 5 V 1.0, 2003-11-26 Application Note TDx5101x Introduction 1 Introduction In Japan operation of RF-Transmitters is allowed without any license if the field-strength at 3m distance is below the limits given in Figure 1: Figure 1 Japanese Radio Regulations As can be easily seen the maximum field strength at 315MHz is 500 µV/m, which is quite low. So the output power of our TDx5101x-transmitters has to be reduced by more than 20dB using a special design of the antenna-matching circuit. Also care has to be taken on the harmonic emissions since the maximum field strength is 35 µV/m there. This requires some additional filtering. App.Note 6 V 1.0, 2003-11-26 Application Note TDx5101x TDK5101F Antenna-Board 2 TDK5101F Antenna-Board 2.1 Schematic Figure 2 App.Note Antenna Board Schematic 7 V 1.0, 2003-11-26 Application Note TDx5101x TDK5101F Antenna-Board 2.2 Layout Figure 3 AntennaBoard_TOP Figure 4 AntennaBoard_Bottom App.Note 8 V 1.0, 2003-11-26 Application Note TDx5101x TDK5101F Antenna-Board 2.3 Bill of Materials Table 1 BOM Table FSK-Mode ASK-Mode R1 open open R2 0R 0R 0603, SMD-Jumper R3 0R 4k7 0603, +/-5% R4 open open R5 0R 0R 0603, SMD-Jumper R6 0R 4k7 0603, +/-5% R7 82k open 0603, +/-5% R8 4k7 4k7 0603, +/-1% R9 15k 15k 0603, +/-5% C1 15p 15p 0603, C0G, +/-1% C2 6p8 6p8 0603, C0G, +/-0,1p C3 open open C4 open open C5 open 1nF C6 10n 10n 0603, X7R, +/-10% C7 330p 330p 0603, C0G, +/-10% C8 18p 18p 0603, C0G, +/-1% C9 10p 10p 0603, C0G, +/-1% C10 47n 47n 0603, X7R, +/-10% L1 0R 0R 0603, SMD-Jumper L2 39n 39n 0603, EPCOS SIMID, +/-2%, B82496C3390G S1 push-button push-button STTSKHMPW, ALPS Q1 9843.75 kHz, CL=12pF 9843.75 kHz, CL=12pF Tokyo Denpa TSS-3B 9843.75 kHz Spec.No. 1053-921 IC1 TDK5101F TDK5101F P-TSSOP-10 IC2 HCS360 HCS360 SO8, Microchip BAT1 battery-holder battery-holder HU2031-1, Renata App.Note 0603, X7R, +/-10% 9 V 1.0, 2003-11-26 Application Note TDx5101x TDK5101F Antenna-Board 2.4 Measurement Results Table 2 Measurement Results Fundamental: 400 µV/m Harmonics: <35 µV/m Current Consumption: 5.4 mA App.Note 10 V 1.0, 2003-11-26 Application Note TDx5101x TDx5101 Antenna-Board 3 TDx5101 Antenna-Board The antenna board of the TDx5101 (16-pin-package) can be found in the specification of the TDA5101. However, investigations revealed that the PA-biasing-resistor R4 has to be changed from 1 kOhm to 4.7 kOhm in order to comply with Japanese Radio Regulations. App.Note 11 V 1.0, 2003-11-26 Application Note TDx5101x Design Considerations 4 Design Considerations 4.1 Output Power Figure 5 shows the effective radiated power as a function of the biasing-resistor. Figure 5 Effective Radiated Power as a function of the biasing resistor On our low-power-evalboards for the Japanese Market a PA-biasing-resistance of 4.7 kOhm is used. Above 9 kOhm the output power is not dependant on the biasing resistor any more due to RF-leakage. That’s why the PA-biasing-resistance must not exceed 6.8 kOhm in order to avoid this operating region. 4.2 Stability The evalboards described above are stable over mass-production. However, if less efficient antennas are used in the application, the PA-biasing-resistor would have to be decreased in order to compensate the additional losses in the antenna. When using a biasing resistor below 3.3 kOhm, an additional resistor of approximately 18 Ohm has to be used in series to the antenna loop in order to damp spurious resonances. App.Note 12 V 1.0, 2003-11-26 w w w . i n f i n e o n . c o m Published by Infineon Technologies AG