TRF1020 GSM Receiver EVM
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Application Brief SWRA018 TRF1020 GSM Receiver EVM Wireless Communication Business Unit This document describes the Texas Instruments (TI™) TRF1020 evaluation module (EVM) board and associated EVM software, which allows the evaluation and the demonstration of the TRF1020 GSM Receiver. Contents Product Support ............................................................................................................................................ 3 The TI Advantage Extends Beyond RF to Every Other Major Wireless System Block......................... 3 Introduction ................................................................................................................................................... 4 Functional Description.................................................................................................................................. 5 Low Noise Amplifier ...................................................................................................................................... 5 RF Mixer ......................................................................................................................................................... 6 First IF Amplifier and IF Mixer ...................................................................................................................... 6 I/Q VCO ........................................................................................................................................................... 6 Second IF Amplifier and I/Q Mixer ............................................................................................................... 6 Serial Control Interface ................................................................................................................................. 6 Table Formats and Styles .................................................................................................................... 7 TRF1020 Schematic....................................................................................................................................... 8 Parts List ........................................................................................................................................................ 9 PCB Layout .................................................................................................................................................. 11 EVM Design Notes....................................................................................................................................... 11 Tank Circuit........................................................................................................................................ 11 Impedance Matching ................................................................................................................................... 13 Low Noise Amplifier and SAW Filter Matching................................................................................... 13 Mixer 1 Output and IF Amplifier 1 Input Matching .............................................................................. 14 Mixer2 Output Matching.............................................................................................................................. 15 IF2 Amplifier/Demodulator Input Matching ............................................................................................... 15 LO1 Buffered Outputs ........................................................................................................................ 15 EVM Tests .................................................................................................................................................... 16 Typical Test Setup ............................................................................................................................. 16 Test Conditions .................................................................................................................................. 16 Typical Performance ................................................................................................................................... 18 Test Data ........................................................................................................................................... 18 EVM Software .............................................................................................................................................. 24 Evaluation Board Disclaimer...................................................................................................................... 24 Digital Signal Processing Solutions 09/22/98 SWRA018 Figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. TRF1020 Functional Block Diagram ....................................................................................... 5 TRF1020 Schematic ................................................................................................................. 8 PCB Layout............................................................................................................................. 11 Varactor Controlled LC Tank Circuit .................................................................................... 12 LNA Input/Output &SAW Filter Match .................................................................................. 13 Tables Table 1. Table 2. Table 3. Table 4. Table 5. 2 Control Word Bit Assignment ................................................................................................. 7 Parts List................................................................................................................................... 9 Evaluation Board Component Summary.............................................................................. 10 First IF Amplifier Gain Control (see Note 1)......................................................................... 17 Second IF Amplifier Gain Control......................................................................................... 17 TRF1020 GSM Receiver EVM Application Brief SWRA018 Product Support The TI Advantage Extends Beyond RF to Every Other Major Wireless System Block S IN G L E C H IP A N A L O G BASEBAND Audio Audio Interface Interface TMS320C54X TMS320C54X Receiver Receiver TRF1xxx TRF1xxx RF RF Interface Interface Synthesizer Synthesizer TRF2xxx TRF2xxx Power PowerAmp Amp TRF7xxx, TRF7xxx, TRF8xxx TRF8xxx DSP DSP Core Core Modulator Modulator TRF3xxx TRF3xxx TSC6000 ASIC BACKPLANE S/W S/W Speaker Speaker Microphone Microphone User User Display Display R F S E C T IO N (C470) (C470) Microcontroller Microcontroller Keyboard Keyboard Op Op Amps Amps S/W S/W SIM SIM Card Card Regulators Regulators ARM7TDMIE ARM7TDMIE S IN G L E C H IP D IG IT A L B A S E B A N D Switches Switches POW ER MGMT Digital Baseband TI’s single-chip Digital Baseband Platform combines two high-performance core processors – a digital signal processor tailored for digital wireless applications and a microcontroller designed specifically for low-power embedded systems. The customizable platform helps wireless digital telephone manufacturers lower component counts, save board space, reduce power consumption, introduce new features, save development costs and achieve faster time to market, at the same time giving them flexibility and performance to support any standard worldwide. Analog Baseband TI analog baseband components provide a Mixed-signal bridge between the real world of analog signals and digital signal processors, the key enabling technology of the digital wireless industry. Using a seamless architecture for wireless communications technology, TI matches its baseband interfaces, radio frequency ICs and power management ICs to digital signal processing engines to create complete DSP Solutions for digital wireless systems. Power Management TI provides power management solutions with integration levels designed to meet the needs of a range of wireless applications. From discrete LDOs and voltage supervisors to complete power supplies for the baseband section, TI power management solutions play an important role in increasing wireless battery life, time-to-market and system functionality. For more information visit the Wireless Communications web site at www.ti.com/sc/docs/wireless/home.htm. TRF1020 GSM Receiver EVM 3 SWRA018 GSM RF System Block Diagram 149 MHz RF BPF 52 MHz IF BPF 2 2 2 ANT 2nd MIXER I out 2 IF Amp 1st MIXER 925960 MHz Div by 4 LPF 2 LNA 0 IF Amp TRF 1020 Receiver T A N K VCO 90 VCO out Serial IF Pwr Dwn&AGC Q out 2 1/M1 1/N1 1st LO 97 MHz to 2nd LO Rx/Tx LO 1074-1109 MHz Duplexer Freq Cont I in TRF7610 PA Level Cntrl Phase Comp 1 Ref Osc Ref Divider Cntrl Pwr Intfc Dwn div by 2 LP Filt PA Driver . Phase Comp 2 Limiter 1/M2 1/N2 0 BPF 90 SSM 880915 MHz FILTER TRF3520 Modulator Pwr Dwn Serial IF VCO T A N K Phase Comp 3 194 MHz 1/M3 1/N3 TRF2020 Synthesizer Q in The TRF1020 is used in conjunction with the TRF3520 Modulator, the TRF2020 Synthesizer, and the TRF7610 Power Amplifier to create a complete GSM solution. Introduction The TRF1020 evaluation board is comprised of a multi-layer printed circuit board and required components. The following information is included to aid in the assessment of this device: q q q q q q q q q 4 Block Diagram and Functional Description Schematic Parts List PCB Layout EVM Design notes Impedance Matching EVM Tests Typical Performance EVM Software TRF1020 GSM Receiver EVM Application Brief SWRA018 Figure 1. TRF1020 Functional Block Diagram I/Q Mixer BUFFER 1 2 IQMX_I+ IQMX_I- BUFFER Divide-by-four To SYNTH ( OS2_DIV4) 48 2nd IF Amplifier 43 44 IF2_IN+ 0 deg IF2_IN- 90 deg Low Pass Filter Buffer 34 Mix2_IF- 35 Mix2_IF+ VCO OS2_BASE 41 OS2_EMIT 39 External Tank SYNTH Loop Filter IF Mixer BUFFER 36 20 Div by 4 2nd LO From Modulator ( Mix2_LO ) 38 To SYNTH ( OS2_SYN) 1st IF Amplifier IF1_IN+ BUFFER 4 5 21 IF1_IN31 Mix1_IF- Buffer IQMAX_Q+ IQMAX_Q- RF Mixer Buffer External SAW Filter 24 BUFFER 29 30 Mix1_IF+ 19 MIX1_RF BUFFER To Transmit Modulator ( OS1_MOD ) 11 DAT 10 CLK 9 12 Dig_GND 16 LNA_OUT 7 Strobe 14 LNA_IN 8 Dig_Vcc LNA To SYNTH ( OS1_SYN ) Serial Interface 7 Dig_CMP External SAW Filter 28 1st LO in ( OS1_EMIT ) Functional Description The TRF1020 is a single-chip Radio Frequency (RF) receiver suitable for 900 MHz wireless Global Systems for Mobile communications (GSM) applications. It combines a Low Noise Amplifier, an RF Mixer, an IF Mixer, two IF AGC Amplifiers, an I/Q Mixer and a buffered VCO into one small package. These functions are described in the following sections. Ample terminals have been reserved to provide for a high degree of signal grounding and to minimize cross talk. Low Noise Amplifier The low noise amplifier (LNA) receives the Gaussian-filtered minimum shift keying (GMSK) modulated carrier signal and boosts the level. Nominal gain of the LNA is 12.4 dB with a Noise Figure of 2.1 dB. The LNA is also capable of switching from +12.4 dB gain state to a -5.8 dB attenuation state. Control of this switching is accomplished using the LNA Gain Control (LNAP) bit of the serial control word. When true, the bias of the LNA to the high gain state is enabled and when false, the amplifier is unbiased. Attenuation is achieved by the off-state isolation of the structure. TRF1020 GSM Receiver EVM 5 SWRA018 RF Mixer The RF mixer utilizes an external oscillator to translate the receive frequency signal to the first intermediate frequency (IF). The mixer’s output is differential open-collector. This enables relatively simple matching to an external high impedance SAW filter. The Applications Evaluation Board uses high side frequency injection for a first intermediate frequency (IF) frequency of 149 MHz. First IF Amplifier and IF Mixer The second downconverter group consists of the first IF amplifier whose output feeds the IF mixer. Because the first IF amplifier output is not brought out to the device terminals, the two functions are specified together. In order to provide for cascaded operation of the first and second IF amplifiers, it is possible to bypass the IF mixer function. Mixer bypassing is accomplished by using the MX2BYP bit (1 = mixer bypassed, 0 = normal operation). The gain for this stage is variable from 0 to 42 dB and is selected by command of the serial control word bits D06 to D11. After amplification, the signal is down converted to 52 MHz using an external local oscillator (LO) frequency of 97 MHz. I/Q VCO The I/Q VCO generates a tone in the 208 MHz range which can be controlled by the voltage applied to the varactor diode on the external tank circuit. A buffered sample of the oscillator output is provided at the OSC2_SYN terminal. The 208 MHz signal is converted to 52 MHz using an on-chip divide-by-4 network then routed to the I/Q Mixer. The divide-by-4 signal is also available through a buffer amplifier at the OSC2_DIV4 terminal. Second IF Amplifier and I/Q Mixer This block provides an additional 42 dB of gain, then down converts the 2nd IF signal to baseband utilizing the on-chip Voltage Controlled Oscillator (I/Q VCO). Gain is variable from 0 to 42 dB and is controlled by the serial word bits D14 through D19. Differential outputs are provided for both the I and Q signals. Serial Control Interface All TRF1020 functional blocks can be individually powered up or down via the serial interface. The TRF1020 device register is manipulated via a synchronous serial data port. The Serial Control Interface provides power up / power down capability for each one of the functional blocks. One 24 bit word is clocked into a temporary holding register with the least significant bit clocked first. The operation register is loaded with the new data residing in the temporary registers using the rising edge of the STROBE input. Table 1 lists the format of the control word. 6 TRF1020 GSM Receiver EVM Application Brief SWRA018 Table Formats and Styles Table 1. Control Word Bit Assignment Bit FUNCTION Signal Name D0 LNA power control LNAP D1 LNA gain control LNAG D2 RF mixer standby MX1STBY D3 RF mixer power MX1P D4 IF mixer power MX2P D5 IF mixer bypass MIX2BYP D6 IF amp 1, gain control bit 1 IF1AGC1 D7 IF amp 1, gain control bit 2 IF1AGC2 D8 IF amp 1, gain control bit 3 IF1AGC3 D9 IF amp 1, gain control bit 4 IF1AGC4 D10 IF amp 1, gain control bit 5 IF1AGC5 D11 IF amp 1, gain control bit 6 IF1AGC6 D12 Demod power control DMODP D13 Demod standby DMODSTBY D14 IF amp 2, gain control bit 1 IF2AGC1 D15 IF amp 2, gain control bit 2 IF2AGC2 D16 IF amp 2, gain control bit 3 IF2AGC3 D17 IF amp 2, gain control bit 4 IF2AGC4 D18 IF amp 2, gain control bit 5 IF2AGC5 D19 IF amp 2, gain control bit 6 IF2AGC6 D20 Demod DC correction DMDISABLE D21 <not used> <not used> D22 <not used> <not used> D23 <not used> <not used> TRF1020 GSM Receiver EVM 7 8 C51 0.1uF A R16 10K 2 +12V 1 B R18 22K R21 22K CW W 2K R26 CCW 10K 9.1K R22 10K R23 R24 AMPLITUDE BALANCE C CCW CW 2 3 5 4 6 MC34071D -12V -12V +12V 7 +12V U3 + 1 R19 10K 56pF CW R17 2K W 56pF CCW OFFSET ADJUST W -12V C45 100pF 10K C19 10K 9.1K R13 10K R15 R14 AMPLITUDE BALANCE ADJUST C46 100pF 13 14 15 16 17 18 19 20 21 22 23 24 10K C26 2 CCW R29 10K VCC C23 1000pF R20 5 - U2 3 10K R12 + 1 CW W OFFSET -12V CW VCC OSI_SYN R25 10K 9 6 5 4 1 5pF C20 C24 L22 C32 P1:I P1:F P1:E P1:D P1:A 0.1uF C50 L7 6.8nH C28 2.7pF D J13 Q_OUT R11 1.5K R9 1.5K R7 1.5K R4 1.5K 1K R5 C44 10pF 1K R10 C43 10pF 1K R8 C42 10pF 1K R6 8 3 7 2 5 6 ISSUED J BRIDGES CHECKED C STOVALL DRAWN APPROVALS P1:H P1:C P1:G P1:B C34 100pF VCC 7 8 9 10 OUT OUT SF1 SF1076A MIX1_OUT J4 1234 IN IN L6 15nH 4pF C25 12 11 0 R33 C41 10pF 47nH L25 OSI_MOD MIX1_LO J6 RF_IN J8 L5 15nH 6.8nH 100pF 100pF C55 1000pF 1pF 50 C57 1pF R41 50 C54 R40 L8 C38 33pF 120nH VCC 330pF C22 L26 3.9nH C37 2pF 330pF 4 5 47nH 3.9nH C29 100pF VCC 180nH L23 C31 T3 ETC1-1-13 3 1 L14 R3 -12V 4 -12V +12V 7 +12V MC34071D 6 C16 1uF 10K CCW R36 W 6 J12 C14 1uF R30 5.1K 100pF C47 U10 TRF1020 7 I_OUT 2 -12V 1 +12V VCC 1000pF OS2_/4 J10 1 C75 2 36 1000pF C2 100pF 3 35 1 C49 0.01uF 48 47 46 45 44 43 42 41 40 39 38 37 3.3pF 4 34 C76 1000pF 5.6pF C87 L18 390nH C58 5 33 2 3 VCC 470nH L2 C80 12pF L12 56nH L9 120nH L10 180nH D L13 8 617PT-1026 T2 C15 39pF 5pF C81 R39 200 100pF C6 5pF 9 29 5 4 C74 L3 180nH C52 0.01uF MIX2_LO J2 L11 150nH 10 28 -12V L16 390nH C86 22pF C1 100pF VCC 9pF C5 0.01uF C10 56pF C21 11 27 C53 56pF L19 120nH R51 0 R50 0 VCO2_BUF VCC 0 R2 C72 1000pF C7 L1 150nH 32 82pF C77 100pF C3 1 1 2 3 VCC 31 IF2_IN J15 C83 5pF C85 0.01uF T1 617PT-1026 5 4 C11 56pF C4 100pF VCC 12 26 4 J21 9pF 12pF CR1 L17 MMBV2109 39nH C82 47K 3 CCW J1 C84 10K VCC R42 CW W L15 390nH 0 R1 C 30 DEM_LO J11 2 1 0 R43 R44 C73 33pF B 25 3 2 1 MIX2_OUT J14 A L27 220pF C35 IN C60 100pF 2 C61 0.01uF 3 2 1 OUT 4 6 GND 1 3 4 5 C59 18pF L28 120nH L29 150nH U1 0 R31 Vin Vout GND TK11230B BYPASS GND CONTROL 5 C27 100pF 4 5 6 -OR- MURATA SAFC942.5MA70N-TC 220pF C48 SF2 F5CH-942M50-L2KM C56 39pF T4 ETC1-1-13 3 1 VIN C62 1uF VCC 0 R32 F C63 1uF IF1_IN J5 C64 100pF E 01/26/98 05/15/98 DATE SCALE: C SIZE NONE DWG. NO. Trf1020.sch TRF1020 SHEET F 1 TRF1020 APPS BOARD 2 1 C REV. J20 1 Wed Sep 02 1998 14:01:18 OF SCHEMATIC DIAGRAM, TEXAS INSTRUMENTS INCORPORATED L4 6.8nH 6pF C66 39nH L21 39nH E 4 3 2 1 SWRA018 TRF1020 Schematic Figure 2. TRF1020 Schematic TRF1020 GSM Receiver EVM Application Brief SWRA018 Parts List Table 2. Parts List Ref. Designator Value Description QTY Part Number Manufacturer C1,2,3,4,6,24,27,29,32, 100pF 34,45,46,47,60, 64 Capacitor 15 GRM36COG Series Murata C5, 84 9 pF Capacitor 2 GRM36COG Series Murata C7,49,52,61,85 0.01 µF Capacitor 5 GRM36COG Series Murata C10,11,19,26,53 56 pF Capacitor 5 GRM36COG Series Murata C14,16,62 1 µF Capacitor 3 TA025TCM105KAR Venkel C15 39 pF Capacitor 1 GRM36COG Series Murata C56 39 pF Capacitor 1 GRM42-6COG Series Murata C20, 21, 81, 83 5 pF Capacitor 4 GRM36COG Series Murata C22,31 330 pF Capacitor 2 GRM42-6COG Series Murata C23, 55, 72, 74, 75, 76 1000 pF Capacitor 6 GRM36COG Series Murata C25 4 pF Capacitor 1 GRM36COG Series Murata C28 2.7 pF Capacitor 1 GRM36COG Series Murata C35, 48 220 pF Capacitor 2 GRM36COG Series Murata C37 2 pF Capacitor 1 GRM36COG Series Murata C38, 73 33 pF Capacitor 2 GRM36COG Series Murata C41,42,43,44 10 pF Capacitor 4 GRM36COG Series Murata C50,51 0.1 µF Capacitor 2 GRM36COG Series Murata C54, 57 1 pF Capacitor 2 GRM36COG Series Murata C58 3.3 pF Capacitor 1 GRM36COG Series Murata C59 18 pF Capacitor 1 GRM42-6 Series Murata C63 1 µF Capacitor 1 GRM42-6Y5V Series Murata C66 6 pF Capacitor 1 GRM36COG Series Murata C77 82 pF Capacitor 1 GRM36COG Series Murata C80, C82 12 pF Capacitor 2 GRM36COG Series Murata C86 22 pF Capacitor 1 GRM36COG Series Murata C87 5.6 pF Capacitor 1 GRM39COG Series Murata L1,11 150 nH Inductor 2 1008CS Series Coilcraft L2 470 nH Inductor 1 LL2012-FR47K Toko L3,10, 23 180 nH Inductor 3 805HS Series Coilcraft L4, 7 6.8 nH Inductor 2 603HS Series Coilcraft L5, 6 15 nH Inductor 2 603HS Series Coilcraft L8, 9, 29 120 nH Inductor 3 603HS Series Coilcraft L12 56 nH Inductor 1 603HS Series Coilcraft L13, 14 3.9 nH Inductor 2 603HS Series Coilcraft L15, 16, 18 390 nH Inductor 3 1008CS Series Coilcraft L17 39 nH Inductor 1 603HS Series Coilcraft L19 120 nH Inductor 1 1008HS Series Coilcraft L21, 27 39 nH Inductor 2 805HS Series Coilcraft L22 6.8 nH Inductor 1 LL1005 Series Toko TRF1020 GSM Receiver EVM 9 SWRA018 L25, 26 47 nH Inductor 2 603HS Series Coilcraft L28 150 nH Inductor 1 805HS Series Coilcraft R1, 2, 31, 32, 33, 43, 50, 51 0Ω Resistor 8 ERJ-2GEJ0R00 Panasonic R3, 13, 15, 16, 20, 22, 23, 25, 29 10 KΩ Resistor 9 ERJ-2GEJ103 Panasonic R4, 7, 9, 11 1.5K Ω Resistor 4 ERJ-2GEJ152 Panasonic R5, 6, 8, 10 1K Ω Resistor 4 ERJ-2GEJ102 Panasonic R14, 24 9.1K Ω Resistor 2 ERJ-2GEJ912 Panasonic R18, 21 22K Ω Resistor 2 ERJ-2GEJ223 Panasonic R30 5.1K Ω Resistor 1 ERJ-2GEJ512 Panasonic R39 200 Ω Resistor 1 ERJ-2GEJ201 Panasonic R40, 41 50 Ω Resistor 2 ERJ-2GEJ500 Panasonic R42 47K Ω Resistor 1 ERJ-2GEJ473 Panasonic R12, 19, 36 10K Ω Adjustable Resistor 3 3214W-103 Bourns R17, 26 2K Ω Adjustable Resistor 2 3214W-202 Bourns R44 10K Ω Adjustable Resistor 1 3296-Y-1-103 Bourns P1 Serial 9-Pin Connector 1 745990-4 Amp J1,2,4,5,6,8,10,11, 12,13,14,15 SMA Connector 12 142-0701-801 EF Johnson J20,21 DC Voltage Connector 2 4-103239-0 Amp U1 Voltage Regulator 1 TK11230 Toko U10 GSM Receiver 1 TRF1020 T. I. U11, 12 Operational Amplifiers 2 MC34071D Motorola CR1 Varactor Diode 1 MMBV2109 Motorola F1 Differential SAW Filter 1 RFM_SF 1076A RF Monolithics F2 Image Reject SAW Filter 1 SAFC942.5MA70N Murata T1, 2 Balun Transformer 9:1 2 617PT-1026 Toko T3,4 Balun Transformer 1:1 2 ECT1-1-13 MA/COM Table 3. Evaluation Board Component Summary Description Quantity Required Capacitors 68 Inductors 27 Resistors 34 Potentiometers 6 Semiconductors 5 Balun Transformers 4 SAW Filters 2 NOTE: Many of the components used are to aid in taking measurements and injecting signals in a 50 Ohm environment. In actual use, the component count could be greatly reduced. 10 TRF1020 GSM Receiver EVM Application Brief SWRA018 PCB Layout The EVM board is comprised of a multi-layer printed circuit board, a TRF1020 device, SMA connectors, and the necessary peripheral discrete components. Figure 3. PCB Layout EVM Design Notes Tank Circuit The VCO generates a signal in the 208MHz range that is used in the downconversion of the IF2 signal to baseband. The 208 MHz signal is later translated to 52MHz through the on-chip divide-by-four circuit. TRF1020 GSM Receiver EVM 11 SWRA018 Figure 4. Varactor Controlled LC Tank Circuit TRF1020 Vtune R42=47K C84=9pF C82=12 pF Terminal 41 OS2_Base 1 J21 2 C81=5pF CR1 MMBV2109 Terminal 40 OS2_Gnd L17=39nH C80=12pF Terminal 39 OS2_Emit NOTE: The tank circuit in Figure 2 has been redrawn in Figure 4 for clarification. The tank resonant frequency is defined by the following formula: f resonance = 1 2π L Ceq 17 where −1 −1 1 1 1 1 Ceq = + + + , CCR1 = Varactor’s capacitance CCR1 C82 C84 C80 On the EVM board, the VCO was designed to operate at 208 MHz. The calculated resonance frequency is as follows: CR1 = 50 pF (at 1.5V, measured on the EVM board) −1 1 1 1 1 Ceq = + + + 9 pF 50 pF 12 pF 12 pF −1 = 13.627 pF , with L17= 39nH f resonance = 1 2π L17 Ceq = 218.32 MHz The difference in frequency between the calculated and measured resonant frequencies is attributed to the actual varactor capacitance, component tolerances, board layout, and the interaction of the TRF1020 with C81. C81 is primarily used to adjust the output power of the oscillator by controlling the feedback current of the internal transistor, but it will have some small effect on the actual resonant frequency. 12 TRF1020 GSM Receiver EVM Application Brief SWRA018 The oscillator frequency tuning range is approximately 6 MHz. The tuning range is controlled by the varactor changing in capacitance when the tuning voltage, (Vtune) is adjusted from 0V to 3.0 V. Vtune is adjusted from 0 to 3Vdc using R44 or can be applied externally at J24 if R43 is removed. The use of high Q components in the tank circuit is required as they affect the impedance seen by the TRF1020. The Q’s of the inductor (L17), the capacitors, and varactors are very critical, as the selection of these components affects the attenuation that the tank circuit will provide. An increase in attenuation reduces the tank resonant signal level and, if not designed properly, can degrade the oscillator start up properties. See the TRF3520 GSM RF Modulator/Driver Amplifier EVM Application Brief, (TI Literature Number SWRA020), for a detailed description of Q and how it can affect oscillator circuits. Impedance Matching Low Noise Amplifier and SAW Filter Matching The diagram below shows the matching circuitry used on the TRF1020 LNA input and image-reject SAW filter. The LNA input impedance matching network primarily determines the gain, noise figure and input return loss performance. A series-C (C32), shunt-L (L7), series-C (C20) matching network is used to obtain optimum noise figure performance. The trade-off for this optimization is degraded input return loss and lower gain. Components L6 and C27 provide a matching network between the LNA output and SAW Filter input. The output of the SAW Filter is matched to the input of Mixer1 with another series-C (C66), shunt-L (L4), series-C (C25) circuit. The two series capacitors, rd (C66 and C25) are critical to the cascaded input 3 -order intercept point performance. The circuitry depicted is a compromise between the best gain, noise figure, input return rd loss, and input 3 -order intercept point. Figure 5. LNA Input/Output &SAW Filter Match Vcc L6=15 nH C32=100pF RF In J8 C20=5pF Terminal 14 L7=6.8nH TRF1020 GSM Receiver EVM C66=6pF C27=100pF LNA Terminal 16 Saw Filter C25=4pF Mix1 In Terminal 19 L4=6.8nH 13 SWRA018 Mixer 1 Output and IF Amplifier 1 Input Matching The output of Mixer 1 is differential and has a real impedance component of 2000 Ohms. This impedance is transformed from 2000 Ohms to 50 Ohms at capacitors C22/C31 using components L8, L9, C21, L10, and L23. The value of C21 is critical for both noise rd figure and input 3 -order intercept point. Depending on the placement of C22 and C31, the signal can either continue through the SAW filter or brought out to measurement point J4 (Mix1 Output), using a 1:1 balun transformer, (T3). Figure 6. Mix1 Output to IF Amp1 Input Match J4 J5 T4 T3 Mix1 Output ETC1-1-13 From Terminal 31 IF Amp 1 Input ETC1-1-13 L28=150nH L10=180nH To Terminal 21 C35=220pF C31=330pF L9=120nH Vcc L26=47pF C21=5pF Mix1 Output L22=6.8nH L27=39nH C29=100pF C38=33pF L25=47pF RFM SF1076A C59=18pF C56=39pF IF Amp 1 Input L21=39nH L8=120nH From Terminal 30 C48=220pF L23=180nH C28=2.7pF C22=330pF L29=120H To Terminal 20 The SAW filter provides 149 MHz filtering and has an input impedance of approximately 850 Ohms. Starting at capacitors C22 and C31, the impedance is transformed from 50 Ohms to 850 Ohms using components C38, L25, and L26. After the filter, the impedance is transformed back from 850 Ohms to 50 Ohms at capacitors C35 and C48 using components C56, L21 and L27. Depending on the placement of C35 and C48, the signal can either continue on to the input of IF Amplifier1 or brought out to connection point J5 (IF1_In), using a 1:1 balun transformer, (T4). With the signal path connected to J5, the IF Amplifier1 can be driven externally. This allows for individual testing of IF Amp1/Mixer2. When cascaded together, Mix1 output, the differential SAW filter, and IF Amp1 input are very sensitive. Small changes in the values of components C21 and C59 will greatly affect the path’s gain, noise figure, and rd input 3 order intercept point. Finally, components L22 and C28 are used to create a resonant trap circuit for the Mix1 LO signal, (Frequency Range 1079-1109), which can couple into the receiver at this point and interfere with proper performance. Again, the tuning utilized is a compromise rd between the best gain, noise figure, and input 3 -order intercept point. NOTE: Much of the impedance matching shown in Figure 6 was to aid in taking measurements and injecting signals in a 50 Ohm environment. In actual use, the cascaded matching circuitry could be greatly simplified. 14 TRF1020 GSM Receiver EVM Application Brief SWRA018 Mixer2 Output Matching Figure 7. Mixer2 Output From Terminal 35 Mix2_Out C73=33pF C11=56pF J14 4 T1 3 Vcc L1=150nH C7=.01uF C72=1000pF Mix2 Out 2 L15=390nH 5 1 617PT-1026 L11=150nH C10=56pF From Terminal 34 9:1 Transformer Mixer 2 translates the 149 MHz signal to a 2nd IF frequency of 52 MHz. Components L1, L11, C10, and C11 create a resonant circuit at approximately 52 MHz. Mixer2 was specified to have a load impedance of 2500 Ohms. The 9:1 balun transformer, (3:1 turns ratio) together with L15 and C73 provide a load impedance of 2500 Ohms to the Mixer2 output while presenting a 50 Ohm impedance to the test environment at connector J14. In particular, the 9:1 balun transforms the 2500 Ohm impedance to approximately 277 Ohms. Finally, L15 and C73 were adjusted to obtain the best gain and complete the impedance transformation to 50 Ohms. IF2 Amplifier/Demodulator Input Matching Figure 8. IF2 Amplifier/Demodulator Input IF2_IN C77=82pF C74=1000pF L2=470nH J15 4 T2 To Terminal 43 3 C76=1000pF C53=56pF 2 L16=390nH 5 1 617PT-1026 L3=180nH C15=39pF C87=5.6pF IF2 In C75=1000pF To Terminal 44 9:1 Transformer The IF2 Amplifier/Demodulator has a specified input impedance of 2500 Ohms. C53, C77 and L16, combined with the 9:1 balun transformer present a 50 Ohm impedance to the test environment at connector J15 and provide a load impedance of 2500 Ohms to the input of the IF2 Amplifier/Demodulator. L3 and C15 form a resonant tank at approximately 52 MHz. L2 and C87 are used to create a 97 MHz trap, (care should be taken as the 97 MHz trap will affect the 52 MHz tank circuit). This trap is necessary to attenuate the Mix2 LO which can couple into the circuit at this point. LO1 Buffered Outputs Os1_ Mod and Os1_Syn, (TRF1020 terminals 28 and 29) are the two available buffered st outputs for the 1 local oscillator input, (LO1). These outputs are not brought out to test points on the TRF1020 EVM. Components L14, R41, C57, L13, R40, and C54 represent typical tuning elements if the outputs are to be used. TRF1020 GSM Receiver EVM 15 SWRA018 EVM Tests Typical Test Setup Figure 9. Typical Test Setup for the TRF1020 EVM Spectrum Analyzer J4, J12, J13, or J14 (Dependant on Test) RF Source J5, J8, or J15 (Dependant on Test) J6 Mixer1 LO Source (LO1) Device Under Test J2 Mixer2 LO Source (LO2) P1 DC Power Supply Test Conditions The tests are performed at room temperature. q q q q q 16 Vcc = +3.0 RF Input = 940 MHz LO1=1098 MHz @ -5 dBm LO2=97 MHz @ -10 dBm I/Q VCO Frequency=208 MHz TRF1020 GSM Receiver EVM Application Brief SWRA018 Table 4. First IF Amplifier Gain Control (see Note 1) IF1AGC6 IF1AGC5 IF1AGC4 IF1AGC3 IF1AGC2 IF1AGC1 GAIN (dB) 0 0 0 0 0 0 0 0 0 0 0 0 1 3.0 0 0 0 0 1 1 6.0 0 0 0 1 1 1 9.0 0 0 1 0 0 0 12.0 0 0 1 0 0 1 14.5 0 0 1 0 1 1 17.5 0 0 1 1 1 1 20.5 0 1 1 0 0 0 23.0 0 1 1 0 0 1 26.0 0 1 1 0 1 1 29.0 0 1 1 1 1 1 32.0 1 1 1 0 0 0 34.5 1 1 1 0 0 1 37.0 1 1 1 0 1 1 39.5 1 1 1 1 1 1 42.0 NOTE: See Table 1, Control Data BIT/Signal Name Map Table 5. Second IF Amplifier Gain Control IF2AGC6 IF2AGC5 IF2AGC4 IF2AGC3 IF2AGC2 IF2AGC1 GAIN (dB) 0 0 0 0 0 0 0 0 0 0 0 0 1 3.0 0 0 0 0 1 1 6.0 0 0 0 1 1 1 8.5 0 0 1 0 0 0 12.0 0 0 1 0 0 1 15.0 0 0 1 0 1 1 18.0 0 0 1 1 1 1 21.0 0 1 1 0 0 0 24.0 0 1 1 0 0 1 27.0 0 1 1 0 1 1 30.0 0 1 1 1 1 1 33.0 1 1 1 0 0 0 36.0 1 1 1 0 0 1 39.0 1 1 1 0 1 1 40.0 1 1 1 1 1 1 42.5 TRF1020 GSM Receiver EVM 17 SWRA018 Typical Performance Test Data LNA/Mix1 (Cascaded Operation) RF = 940 MHz @ -50 dBm, LO1 = 1089 MHz @ -5 dBm, IF1=149 MHz, (Measurements include filter loss) Test No Parameter Conditions Typical Test Results Min Typ Max Units 1 Gain Max LNA Gain Min LNA Gain 25 dB 2 3 Noise Figure 3rd-order Intercept Point (200 kHz tone separation) 27 29 6.8 dB Max LNA Gain Min LNA Gain 3.8 4.5 dB 6.8 dB Max LNA Gain Min LNA Gain -9.0 dBm 9.0 dBm NOTE: Input RF power level may need to be increased in order to measure 3rd-order Intercept point. IF1/Mix 2 Input Frequency = 149 MHz @ -75 dBm, LO2 = 97 MHz @ -10 dBm, IF2 = 52 MHz Test No Parameter Conditions Typical Test Results Min Typ Max Units 4 Gain Delta Max Gain 39 dB 5 Gain Step Error See Table 2 6 Noise Figure (SSB) 7 Input 3rd-order Intercept Point 42.5 9.4 Max Gain Min Gain 46 +1 -52.5 -9.6 dB 15 dB dBm dBm (200 kHz tone separation) NOTE: Gain error relative to gain state in Table 2. 18 TRF1020 GSM Receiver EVM Application Brief SWRA018 VCO Test No Parameter 8 Conditions Typical Test Results Min Typ Max Units Frequency Range 206212 MHz 9 Output power -14.5 dBm 10 Phase Noise -120 dBc/Hz 200 kHz Offset NOTE: The EVM is configured to use the on-board Vcc and R44 for frequency tuning. To apply an external tuning voltage, R43 must be removed. IF2/Demodulator Input Frequency = 52.1 MHz @ -75 dBm Test No Parameter Conditions Typical Test Results Min Typ Max Units 11 Gain Delta Max IF Gain 37 dB 12 Gain Error See Table 3 13 14 42 47 +1 dB Amplitude Balance + .7 dB Phase Balance +1 deg NOTE: Gain error relative to gain state in Table 3. LNA/Mix2 (Cascaded Operation) RF = 940 MHz @ -85 dBm, LO1 = 1089 MHz @ -5 dBm, LO2 = 97 MHz @ -10 dBm, (Measurements include filter losses) Test No Parameter Conditions 15 Gain Max IF Gain 56 dB 16 Noise Figure IF1 Gain=42 dB IF2 Gain=42 dB 4.8 dB Typical Test Results Min Typ Max Units NOTE: For maximum IF Gain control range, C28 should be changed to 4 pF. C22, C31, C35, and C48 must be properly oriented for cascaded operation. TRF1020 GSM Receiver EVM 19 SWRA018 LNA/Demodulator (Cascaded Operation) RF = 940.1 MHz @ -108 dBm, LO1 = 1089 MHz @ -5 dBm, LO2 = 97 MHz @ -10 dBm, VCO enabled (Measurements include filter losses) Test No Parameter 17 IF Amplifier Gain Control Range 18 Noise Figure Conditions IF1 Gain=42 dB IF2 Gain=30 dB Typical Test Results Min Typ Max Units 0 to 80 dB 5.5 dB NOTE: For maximum IF Gain control range, C28 should be changed to 4 pF. C22, C31, C35, and C48 must be properly oriented for cascaded operation. 20 TRF1020 GSM Receiver EVM Application Brief SWRA018 LNA to Mixer 1 Gain • • • • RF In = 940 MHz @ -50dBm LO = 1089 MHz @ -5 dBm Cable/Balun Transformer Loss = 1.7 dB LNA/Mix1 Gain = |-50 - (-24.62)| +1.7 dB = 27.08 dB TRF1020 GSM Receiver EVM 21 SWRA018 LNA to Mixer 1 Input 3rd Order Intercept Point • • • • RF1 In = 940 MHz @ -45dBm, RF2 In = 940.20 MHz @ -45dBm LO = 1089 MHz @ -5 dBm Cable/Balun Transformer Loss = 1.7 dB IIP3 = |(-74.8/2)| - 45 = -7.6 dBm NOTE: Input power was increased from the specified –50 dBm to –45 dBm in order to measure rd the 3 order product above the noise floor. 22 TRF1020 GSM Receiver EVM Application Brief SWRA018 LNA to Mixer 2 Gain • • • • • RF In = 940MHz @ -85dBm LO1 = 1089 MHz @ -5 dBm LO2 = 97 MHz @ -10 dBm Cable/Balun Transformer Loss = 1.7 dB LNA/Mix2 Gain = |-85 - (-29.93)| +1.7 dB = 56.8 dB TRF1020 GSM Receiver EVM 23 SWRA018 EVM Software Windows-based software is supplied with the evaluation board. The software is intended for use in a Windows environment, 3.11or later version, Windows 95 or Windows NT. No special memory is required to use the software. q TRF1020.EXE The TRF1020.exe file may be copied to the system hard drive or may be executed directly from the disk provided. To execute the program from the provided disk, simply type the following. A:\TRF1020 ↵ (Enter) The program executes from the TRF1020.EXE file. Connect the interface cable to the computer LPT port, then connect the cable to the EVM. The EVM software allows you to select the correct LPT port. Port selection is found under the Options menu. The TRF1020 functional blocks can be activated or deactivated individually by selecting the corresponding button on the EVM software display. Available selections are First Mixer Power, First Mixer Standby, Second Mixer Power, Second Mixer Standby, DeModulator Power, DeModulator Standby, LNA Bias, IF1 Gain, and IF2 Gain. To activate or deactivate a block, simply click on the desired state with the mouse. Once the functional blocks have been selected, select SEND with the mouse to enable the selected device state. SEND can be found at the top/center of the EVM software window. Evaluation Board Disclaimer Please note that the enclosed evaluation boards are experimental Printed Circuit Boards and are therefore only intended for device evaluation. We would like to draw your attention to the fact that these boards have been processed through one or more of Texas Instruments’ external subcontractors which have not been production qualified. Device parameters measured, using these boards, are not representative of any final datasheet or of a final production version. Texas Instruments does not represent or guarantee that a final version will be made available after device evaluation. THE EVALUATION BOARDS ARE SUPPLIED WITHOUT WARRANTY OF ANY KIND, EXPRESSED, IMPLIED OR STATUTORY, INCLUDING BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEXAS INSTRUMENTS ACCEPTS NO LIABILITY WHATSOEVER ARISING AS A RESULT OF THE USE OF THESE BOARDS. 24 TRF1020 GSM Receiver EVM Application Brief SWRA018 References TRF1020 GSM Receiver, Literature number SLWS028 TRF3520 GSM RF Modulator/Driver Amplifier EVM, Literature number SLWA020 TRF2020 Frequency Synthesizer, Literature number SWRA012 TRF7610 Silicon Mosfet Power Amplifier IC for GSM, Liter ature number SLW5059 European Telecom Standards Institute Specification, 05.05 Radio Transmission & Reception European Telecom Standards Institute Specification, 11.10 Mobile Station Conformity Specifications TRF1020 GSM Receiver EVM 25
