SURFACE ACOUSTIC WAVE FILTER Murata Manufacturing Co., Ltd.
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P06E3.pdf 01.10.24
SURFACE ACOUSTIC WAVE FILTER
Murata Manufacturing Co., Ltd.
P06E3.pdf 01.10.24
Introduction
Murata continued research surface acoustic wave filters since 1970. 1976 offered sale first surface acoustic wave filter used highfidelity tuners. This product attracted attention world, because surface acoustic wave filter applied electronic equipment consumer first time world. Then, successfully developed offered sale surface acoustic wave filter video color television sets. developments technology made television sets smaller size, which improving their performance year after year. With discrete circuit integrated come when most circuitry television set, with exception power supply tuner, composed just transistors. surface acoustic wave filter video circuits television succeeded making filter block into solid state device previously left behind integration. Murata recently developed compact, high performance resin mold type package surface acoustic wave filters.
P06E3.pdf 01.10.24
CONTENTS
Terms Surface Acoustic Wave Filters YYYYY02 Features Fundamentals
3-1. Electrode Pattern Design 3-2. Substrate 3-3. Photolithography 3-4. Sputter 3-5. Assembly 3-6. Electrical Characteristics 3-6-1. Amplitude characteristics.07 3-6-2. Phase Characteristics.07 3-6-3. Insertion Loss 3-6-4. Measurement Circuit 3-6-5. Measurement Method.10
Terms Surface Acoustic Wave Filters Features
Fundamentals
Application
Appendix
Application
4-1. Connection Surface Acoustic Wave Filter with Other Blocks 4-1-1. Input/Output Impedances Respective Blocks 4-1-2. Connection Tuner Stage 4-2. Application Circuit 4-2-1. Preamplifier System 4-2-2. Postamplifier System 4-2-3. Method Compensation Insertion Loss without Amplifier
Appendix
5-1. Detection Methods Specification Surface Acoustic Wave Filter 5-2. Direct Breakthrough 5-3. Impedance Surface Acoustic Wave Filter 5-4. Reliability Test 5-5. Notice (handling)
P06E3.pdf 01.10.24
Terms Surface Acoustic Wave Filters
Acoustic Wave (SAW) acoustic wave, propagating along surface elastic substrate, whose amplitude decays exponentially with substrate depth. Acoustic Wave Filter (SAW Filter) filter characterized surface acoustic wave which generated propagates along substrate surface receiving IDT. Coupling Coefficient electromechanical coupling coefficient defined 2|V/V|, which means efficiency transform electrical energy into acoustic energy vice versa. (Interdigital Transducer) comb structure consisting interleaved metal electrodes whose function transform electrical energy into acoustic energy vice versa means piezoelectric effect. element comb electrode. common electrode connecting individual fingers together. Overlap length finger pair between which only electromechanical interaction generated. Weighting produced change finger overlap. Maximum finger overlap length Unwanted signals filter which three times traversed propagation path between input output IDT's. Wave Signals Unwanted signals caused bulk wave excitation, which suppressed grooving bottom substrate. Surface acoustic wave propagates right left because IDT's symmetrical construction. Silicon rubber coated outer side IDT's damp surface acoustic wave propagates outer side. Through Signals Unwanted signals from input appearing filter output coupling stray capacitances other electromagnetic couplings.
Input mark
Fig.1 Dimensions
10max.
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Features
Provides same characteristics conventional filter block with adjustment. Labor saving color television circuit assembly line. Make circuit compact integrated. Extremely beautiful television pictures possible. Temperature coefficient trap frequency small. Resin molded type available prices. Shares very small space P.C.B.
P06E3.pdf 01.10.24
Fundamentals
3-1. Electrode Pattern Design
basic configuration surface acoustic wave filter IDTs surface piezoelectric substrate. first connected signal source generates surface acoustic wave, which propagates along substrate surface second IDT, which transforms energy into electrical voltage load connected IDT. Frequency characteristics IDTs calculated means impulse model. case Normal which constant pitch constant overlap, corresponding impulse shown Fig.2 below. When voltage IDT, direction voltage direction interval. voltage then subjected expansion shrinkage substrate piezoelectric effect. impulse pair adjacent positive negative polarities correspond electrode pair. When wavelength surface acoustic waves generated each impulse equal electrode pitch maximum energy. Wave velocity electrode pitch number electrode pair then frequency characteristics normal calculated equations shown below. A(f) where Frequency characteristics changed easily means weighting. There mainly used weighting method. Varying Finger Overlap (magnitude impulse), called "apodize". Varying pitch (position impulse), called "variable pitch." Assuming that impulse magnitude including signs time summation waves given equations shown below. This represents Fourier transformation itself. Since impulse uniquely determined when electrode pattern given, frequency characteristics determined applying Fourier Transformation. Optimum pattern that correctly meet specification designed means computer simulation. aie-j2fti
Finger
Impulse
Fig.2 corresponding impulse
Attenuation (dB)
Frequencies (MHz)
Fig.3 Frequency characteristics normal
Fig.4 Weighted impulse
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Fundamentals
3-2. Substrate
ZnO, single crystal usually used substrate materials surface acoustic wave filters. Substrates specifically available surface acoustic wave filter color television sets should satisfy following conditions: surface acoustic wave electromechanical coupling coefficient large. effective dielectric constant proper. Propagation velocity small temperature coefficient. Propagation loss surface wave small. Stable against heat little change aging. Cost producing substrate low. material constants in/between substrates have little dispersion. characteristics through refer electric properties surface acoustic wave filter, refer reliability, refer price product. larger electromechanical coupling coefficient mentioned (1), smaller insertion loss surface acoustic wave filter. other hand, dielectric constant substrate related impedance surface acoustic wave filter. temperature coefficient propagation velocity mentioned determines temperature coefficient center frequency filter. Presently, there substrate fulfilling requirements listed above, available materials have both advantages disadvantages. Since surface acoustic wave filter color television needs relatively large substrate size, substrate material cost should possible. Using well established sputter techniques, Murata provides high performance substrates very cost. Single crystal substrates relatively expensive despite good reproducibility stability.
Substrate materials LiNbO3 LiTaO3 ZnO/glass*
Non-alkaline glass
Crystal Propagating Temperature Dielectric Direction Velocity Coefficient Constant (m/sec.) (ppm/°C) 128° Rotated 112°Y 3994 3296 2600
Table Properties substrate materials surface acoustic wave filters
3-3. Photolithography
This technique forming fine electrodes substrate. Process producing photomasks based designed data, coating resist onto aluminum evaporated substrate, which photomask radiating ultraviolet rays onto photomask forming etching unwanted aluminum. Surface acoustic wave filter treating 58MHz television frequency more than fine finger electrodes, which width about micrometers. Surface acoustic wave filters being manufactured fully automated production line strictly environmental controlled room, fear disconnection shorting dust.
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Fundamentals
3-4. Sputter
purpose getting piezoelectric thin film glass, must deposited glass substrate sputtering. simplified sputtering apparatus shown Fig.5. First, berzia pumped high vacuum, then pressure argon oxygen flow. Then, high frequency voltage ceramic target (cathode) that argon ionized. Ionized argon goes target, makes target composing element sputtered out. These eventually coated onto portions glass substrate. Murata established stable technique that produce high performance thin film with high deposition rate variation axis orientation.
Berzia
Glass Plate
Shutter
Target
Vaccum Pump
Magnet O2+Ar Voltage Supply
Fig.5 Sputtering apparatus
3-5. Assembly
Lead soldered directly substrate shown Fig.6 below, thus providing strong steady connection. This connection danger lead wire breaking caused vibration corrosion caused humidity conventional wire bonding connection. Resin mold caves surface substrate formed processes described below. First, coated electrodes element. Then element coated with resin dipping. When resin cured, melted heat absorbed into resin capillary phenomena, while caves formed surface substrate. first layer external resin expansion coefficient resin used Murata's CERAFIL®. second layer moistureresistant precise resin. (SAFGH Type)
Resin mold
Absorber
Lead Glass
thin film
Fig.6 Construction filter (SAFGH Type)
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Fundamentals
3-6. Electrical Characteristics
3-6-1. Amplitude characteristics
Fig.7 shows characteristics surface acoustic wave filter television circuit. Being remarkably different from conventional filters, filter response many peaks bottoms outside pass band. necessary items spurious attenuation upper side lower side.
Attenuation (dB) 1800 1600 1400 1200 1000 Group Delay Time (nsec.)
3-6-2. Phase Characteristics
case surface acoustic wave filters, output signal delay with regard input signal, corresponding time propagation from input output surface acoustic wave. example, when thin film sputtered glass used piezoelectric substrate, propagation velocity surface acoustic wave approximately 2600m/sec. distance between input output 3mm, propagation time surface acoustic wave will approximately 1.2µ sec. Since delay time surface acoustic wave filter relatively large shown above, gradient phase with regard frequency large, result, hard observe phase linearity measuring phase characteristic. view these facts, more convenient observe variations group delay time. SAFGN58M7VH0Z00B03 (shown Fig.7) designed properly compensating group delay time chroma bands. Since short cycle ripple group delay time critically affect performance these filters, sometimes included specifications filter. this case, ripple defined maximum value difference between neighbouring peak valley. ripple chiefly caused (Triple Transit Echo) most cases, also caused direct breakthrough.
Frequency (MHz)
Fig.7 Frequency characteristics SAFGN58M7VH0Z00B03
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Fundamentals
3-6-3. Insertion Loss
terms express loss there insertion loss power loss. some cases there confusion regarding these terms, here introduce term more, i.e., voltage loss, make clear distinction between definitions each term follows; Fig.8 signal source voltage, output voltage, signal source impedance, load impedance. insertion loss defined ratio output voltage when filter removed short circuited jumper wire, shown Fig.8 (b), maximum output voltage when filter inserted. this case, attention should paid fact that insertion loss ratio signal source voltage output voltage Even when ratio constant, insertion loss changed when ratio changed. this brochure ratio signal source voltage output voltage i.e., (VS/VL) defined voltage loss. From considerations presented above, following relation obtained: Insertion loss Voltage loss
Fig.8 Effect power dissipation incorrect insertion filter
Power loss defined ratio available power signal source power supplied load follows: Power loss (VS2/4RS) (VL2/RL) (VS/VL) (RL/4RS) Thus, Power loss Voltage loss (RL/4RS)
From obtain following relation: Power loss Insertion loss RL)2 4RSRL
From possible that when have: Power loss Insertion loss following considerations developed based upon definitions above. power loss filter determined relation impedance filter itself terminating impedances imput output sides. Close center frequency filter, input output impedances filter itself expressed capacitance resistance parallel. This resistance called radiation resistance, power consumed this resistance becomes surface wave energy. Thus, power loss reduced performing effective consumption power this radiation resistance. When signal source impedance load impedance
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Fundamentals
purely resistive, assuming equal absolute value input impedance filter, equal absolute value output impedance Zout filter, power loss becomes minimum.(*) Strictly speaking, condition minimum power loss slightly differs from condition Zout Since Zout have capacitive components, power loss further decreased performing cancellation these capacitive components means inductance, matching remaining pure resistive components with this case power loss actually minimized thanks conjugate impedance matching. described above, power loss reduced means impedance matching input/output impedances filter, known that level (Triple Transit Echo) power loss conflicting relation, i.e., when power loss reduced increases. required suppression cases practical -40dB, order attain that value, said theoretically that power loss filter should larger than 16dB. Thus, cases practical application, instead matching perfectly, filter mismatched some extent, with power loss larger than 16dB order make possible certain margin safety, actual value power loss should larger than 18dB).
3-6-4. Measurement Circuit
Fig.9 shows measuring circuit SAFGN58M7VH0Z00B03. reduce power loss, parallel tuning coil used. Since insertion loss filters large, output signal becomes low. feed through signals make accurate measurement difficult, requiring attention shielding test fixture.
TA7124P
15pF
0.75µH
1.1µH
SAFGN58M7VH0Z00B03
Fig.9 Measuring Circuit
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Fundamentals
3-6-5. Measurement Method
means network analyzer Amplitude phase, group delay time characteristics measured directly means network analyzer. Network analyzer this made several makers. Surface acoustic wave filter video television sets many specified points. Murata adopted synthesizer type programmable network analyzer, which measures quickly accurately, judges specifications automatically. time domain measurement system used verify spurious levels TTE, etc., shown Fig.10. Typical pulse responses shown Fig.11. Pulse rise time should optimally long, because "ears" appear response waveforms band limitations filter which disturbs measuring.
Input Main Signal Edge Reflection, Bulk Wave Direct Breakthrough Time Time
TTE=20log
Fig11 Typical Pulse Response Waveform
Annstu MG411B
Pulse Generator
Amp.1 Generator Mixer 10514A Picture Carrier Frequency Zin=Zout=50
Amp.2
Attenuator
Zin=Zout=50
Amp.3
Oscilloscope
National VP-5520A Amp.1 Amp.2 Amp.3 8447A(20dB Gain)
T=200 nsec.
Fig.10 Block Diagram Pulse Response Measurement System
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Application
4-1. Connection Surface Acoustic Wave Filter with Other Blocks
4-1-1. Input/Output Impedances Respective Blocks
most common method compensate high insertion loss filter putting amplifier. this case, connection four stages listed below becomes very important order filter perfectly. Tuner filter Amplifier compensation insertion loss chip color television stage. described before, characteristics filter (especially insertion loss TTE) influenced impedance matching. order connect filter stages before after, must cleverly consider facts described above. first time will calculate impedance each stage. Tuner Since most tuners coaxial cable, their nominal output impedance (50). other hand, consequence popularization electronic tuner, which sometimes connected Stage directly without coaxial cable mounting tuner main television set. this case tuner designed have high output impedance. Filter input output impedances filter determined piezoelectric substrate material mainly. described previously, equivalent circuit filter expressed resistance capacitance parallel series (Fig.12). Table presents results actual measurements performed with filters manufactured Since capacitance cancelled when parallel coil put, impedance filter (including coil parallel) center frequency given this case value impedance becomes larger than value tuning impedance Rp//Cp. When series coil put, parallel expression Fig.12 should changed into series expression Fig.12 (b). Since this case tuning coil series resonance, impedance filter (including tuning coil) becomes equal This value smaller than impedance filter without tuning coil (Rp//Cp). Amplifier compensation insertion loss. Amplifier compensation insertion loss composed discrete bipolar transistor, cost. Now, assume that amplifier configuration mentioned above. Used with emitter grounding, amplifier will have input impedance, order 100. output impedance depends upon resistor connected collector, this resistor small value gain amplifier reduced,
Input Output 6.6pF 5.2pF 3.4pF 8.4pF 1.7k 6.2pF 6.9pF 4.0k 5.0pF 4.7pF 3.3pF SAFGN58M7 VH0Z00B03 2.1k 8.1pF SAFGN45M7 VA0Z00B03 4.9k 6.8pF SAFGN38M9 VZ0Z00B03 4.7pF
Table Equivalent Circuit Constants filters
Parallel expression
Series expression
Fig.12 Equivalent Circuits Surface Acoustic Wave Filter
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Application
large value, output impedance transistor itself will upper limit. Thus, order useful. chip input impedance chip television order
1000
1000 1000
2200
1000 (a')
4-1-2. Connection Tuner Stage
When using filter, importance relation with impedances stages located after before filter already described. addition, connection between tuner next stages requires special attention. shown Fig.13, there many types output circuits tuner. most commonly used circuit that shown (a), double tuning system (c), cascade circuit also used. output frequency characteristics tuner depend upon circuit used. overall frequency characteristic television determined combination frequency characteristic tuner output stage frequency characteristic filter. Thus, even when overall characteristic stage television known, required frequency characteristic filter changed characteristic tuner, used together with filter, changed. other words, there filter with given characteristic, necessary connect with tuner presenting characteristics conveniently matched with filter. example, combine stage tuner with single tuning output circuit, some cases, required make resonant circuit between output circuit tuner input circuit stage, shown Fig.14, virtually performing double tuning circuit. this case, stage removed replaced filter, circuit will single tuning one, result overall bandwidth become narrower. When overall bandwidth narrow, most simple solution resistor parallel with input stage damp circuit widen output bandwidth. However, this action makes voltage level reduced, recommended change tuner with another have wider bandwidth. order increase bandwidth output stage, must adopt double tuning shown Fig.13 (b), damp circuit means damping resistor, shown cascade circuit used fear gain reduction Qdamping also improve stability circuit. other hand, circuits like that shown (a), possible widen bandwidth changing circuit constant, shown (a'). nominal output impedance tuner actual cases often strong frequency dependence shown
1000 1000 1000
1000
1000 1000
1000 1000 1000
Fig.13 Various Types Output Circuit Tuner
Tuner Coaxial Cable
Stage
Trap
Fig.14
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Application
Fig.15. Figure corresponds Fig.13 with popular type circuit, Fig.15 corresponds Fig.13 with double tuning circuit. Fig.15 corresponds case Fig.13 (a'), this circuit output impedance very weak frequency dependence. Connecting tuner output filter directly (for example, case post amplifier system described later), strong frequency dependence tuner output impedance difficult problem. Reactance tuner output changing frequency frequency will change tuning state filter make shape amplitude characteristics filter change from one. Thus, post-amplifier system desirable tuner with nearly constant output impedance, shown Fig.15 (c). other hand, preamplifier system described later, output impedance changing tuner difficult problem, being sufficient consider only bandwidth output stage. other words, since preamplifier plays role buffer, filter connected after influenced tuner output impedance.
R/Z0
Z0=75
Fig.15 Output Impedance Tuner
R/Z0
R/Z0
Z0=75
Z0=75
Fig.15 Output Impedance Tuner
Fig.15 Output Impedance Tuner
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Application
4-2. Application Circuit
4-2-1. Preamplifier System
system system where insertion loss compensation amplifier placed before filter called preamplifier system. Fig.16 example preamplifier system, converted into configuration shown Fig.16 operation. value shown Fig.16 controlled changing value other hand, also controlled changing value described previously, insertion loss filter depends upon impedance matching. make external terminating impedance equal impedance filter (impedance filter including tuning coil, when such coil used), gets minimum insertion loss. filter should mismatched order suppress TTE. When tuning parallel tuning, making terminating impedance mismatched lower side makes reduced that ripple group delay time characteristic reduced shown Fig.17). contrary, mismatching higher side makes increase. small bring high power loss, values must determined with making compromise between suppression voltage gain. case series coil tuning situation inverse. shown Fig.18, when external terminating impedance mismatched higher side, reduces.
Rs=1k
Rs=560
Group Delay Time
100nsec.
Rs=220
Rs=150
15pF
1.1µH
0.75µH
Fig.17 Relation between Terminating Impedance Ripple Group Delay Time Characteristic (Parallel tuning)
Rs=1k
Group Delay Time 100nsec.
Rs=220
Tuner chip
Rs=75
Rs=25
Fig.16 Preamplifier System
0.68µH
Fig.18 Relation between Terminating Impedance Ripple Group Delay Time Characteristic (Series Tuning)
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Application
referring gain preamplifier system. Fig.20, since capacitance filter, transistor cancelled means coil connected parallel, only resistive component taken into consideration. simplified equivalent circuit Fig.19 will have final configuration shown Fig.20. circuit shown Fig.20, considered equivalent actual working state Fig.19. last circuit used test circuit. Fig.20 voltage gain between input output expressed (e0/ei) Assuming insertion loss filter (dB) (L>0), output voltage when (equivalent situation with filter removed short circuited jumper wires), following relation valid: Thus, from definition insertion loss have: (e0/ei) 20log (E0/ei) RL)) Assuming power loss filter K(dB), equations 3-6-3, give following equation. (RL/4RS) order increase value values (RL/4RS) should increase value should reduced. However, should more than order suppress TTE. voltage gain preamplifier, depends upon collector current transistor. When source voltage given, maximum output level determined consequence linearity amplifier, thus, actual cases voltage gain preamplifier considered constant. Consequently, only (RL/4RS) remains undetermined. RL/RS should large possible, power loss order dB). example, power loss filter assumed 16dB (constant), total voltage gain RL/RS will present relation shown Fig.21. Fig.21 shows that when gain preamplifier constant, total gain increases with ratio RL/RS. preamplifier system Since signals preamplifier amplified high levels, necessary prevent distortions intermodulation. insert resistance negative feed back emitter commonly used. preamplifier system suited high impedance filters. Using impedance filter with preamplifier system, values shown Fig.20 will very fear TTE, result gain preamplifier, reduced. preceeding chapter, change could
Filter
Fig.19
eigm
Filter
Where Output resistance Input resistance
eigmRs Filter
Where Rs=Rc//R1 RL=Rin//R2
Fig.20
Power Loss Filter=16dB(constant) Total Vpltage Gain (dB)
20log(gm
Rs)=26d
23dB 20dB
17dB
RL/Rs
Fig.21 Relation between Total Voltage Gain RL/RS
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Application
compensated changing result changing collector current, resulting therefore constant value However, when value small, collector current limited maximum collector dissipation, become high. Consequently possible compensate reduction using impedance filters preamplifier system, following modifications required. impedance filter preamplifier system. impedance conversion circuit required impedance filter preamplifier system. Fig.22 shows example impedance filter preamplifier system. well-known impedance conversion circuit using transformer down shown Fig.23 modified circuit shown Fig.23 with capacitance down, capacitance filter Fig.22 corresponds capacitance Fig.23 (b). coil plays part transformer well tuning coil. Fig.23 equivalent transformation ratio given C2), impedance ratio given C2)2. Thus, arbitrary impedance transformation attained selecting convenient value circuit Fig.22, impedance input side filter reduced stepping-down, output side impedance increased stepping-up. Thus, this case possible impedance filter with same peripheral circuit used case high impedance filter.
Transformation Ratio n1:n2
Transformation Ratio(C1+C2):C1
Fig.23 Transformation Circuits
Tuner
chip
Fig.22 Circuit Using Low-impedance Filter Preamplifier System
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Application
4-2-2. Postamplifier System
system system using amplifier compensation insertion loss after filter called postamplifier system. Fig.24 shows example postamplifier system. postamplifier composed emitter grounded bipolar transistor, input impedance will have value order 100. Usually output impedance tuner nominal value external terminating impedances postamplifier system changed easily preamplifier system. When both input output high impedance filter terminated mismatching rate much, resulting large insertion loss, necessary modify circuit described below section. When impedance filter terminated both suppression insertion loss arranged suitable value. However, since input impedance filter seen from tuner perfectly frequency characteristic output stage tuner sometimes influenced filter impedance. example, input impedance filter larger than factor output circuit tuner becomes high, result bandwidth become narrower. prevent this, necessary insert damping resistor parallel with input terminals filter. about relation between power loss filter noise figure postamplifier system postamplifier system, reason signal level after filter, they suspect deterioration noise figure. noise figure block diagram shown Fig.25 should discussed. Here, order simplify discussion, filter assumed attenuator with gain Assuming that only thermal noise generated, that both tuner filter have same bandwidth noise figure filter will expressed follows: (Sin/kBTB) (Sout/Nout (Sin/kBTB)
Tuner
1chip
Fig.24
Tuner Noise Figure Gain
Filter
Sout
Post Amplifier
Fig.25
Noise Figure System F(dB)
Ft=3dB Ft=5dB Ft=7dB
Gt=40dB Gt=35dB Gt=30dB Gt=25dB
(1+Gf )kBTB
Where Boltzman's constant, absolute temperature filter, bandwidth Nout output noise level. noise figure this system will given
Tuner
Filter
Post Amplifier Fa=20dB Ga=3dB
Fv=8dB
Constant
Power Loss Filter (dB)
Fig.26 shows relation between power loss filter noise figure total system, with
Fig.26
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Application
Noise Figure System F(dB)
tuner gain tuner noise figure taken parameters. According Fig.26 condition that tuner gain larger than 30dB, deterioration noise figure total system does exceed even when power loss filter 24dB. Thus, when using filter postamplifier system desirable connect high gain tuner, order prevent deterioration ratio high input level, desirable tuner which higher signal level which begins operate. (i.e., Handling signal level mixer transistor FET) tuner high). Fig.27 shows calculation results noise figure total system assuming postamplifier noise figure 2dB, 4dB. These results show that noise figure postamplifier less effective upon noise figure total system than gain noise figure tuner, Fig.28 presents calculation results noise figure total system assuming that noise figure 6dB, 10dB. curves almost superimposed. result, deterioration ratio insertion loss filter avoided using convenient tuner. high impedance filter postamplifier system. have said that impedance filter better postamplifier system because terminating impedance filter limited low, high impedance filters also usable means series coil tuning, described below. filter impedance expressed means parallel expression series expression, shown Fig.12, which converted mutually. series coil tuning, easier analyze with equivalent circuit with series expression. Tuned with series coil, apparent impedance filter becomes (Rso). Table shows (Rso) series expression very small compared with (Rpo) parallel expression. impedances high impedance type filter SAFGN58M7VH0Z00B03, SAFGN45VA0Z00B03 become very order Thus, even high impedance filters used postamplifier system means series coil tuning. Fig.29 shows example circuit using high impedance type filter postamplifier system. Since output side filter connected postamplifier, which input impedance order 100, which brings heavy mismatching. input side filter close matching thanks series tuning coil, whole total power loss becomes high suppress TTE.
Noise Figure System F(dB) Tuner Gf=33dB Filter Post Amplifier Ga=20dB
Fa=2dB Fa=3dB Fa=4dB
Fv=8dB
Power Loss Filter (dB)
Fig.27
Fv=6,8,10dB Tuner Gf=33dB Filter Post Amplifier Ga=20dB
Curves Superposed
Power Loss Filter (dB)
Fig.28
Tuner
chip
Fig.29 High Impedance Type Filter Postamplifier System
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Application
4-2-3. Method Compensation Insertion Loss without Amplifier
gain chip increased, possible leave insertion loss compensation amplifier, shown Fig.30. From another point view, possible that postamplifier described previously absorbed chip Now, power loss voltage loss related follows, described 3-6-3, Power loss Voltage loss (RL/4RS) Assuming that power loss certain value (const.) suppress TTE, voltage loss made small increasing RL/RS ratio. output impedance tuner, which signal source filter, assumed have fixed value other hand, generally input impedance chip VIF, load side, relatively high, order Thus, desirable without reducing impedances have fixed values, like this case, necessary modify circuit constants adopt filter given conditions. Fig.31 shows examples circuits with high impedance type filter impedance type filter, respectively. case high impedance type Fig.31 (a), output side tuned means parallel coil, practically matched with load impedance. impedance case Fig.31 (b), since impedance filter value, order several hundred Ohms even when tuned parallel coil, impedance increased means transformation circuit like that described 4-2-1. both circuits attain insertion loss approximately 12dB, result, amplifier compensation insertion loss abridged, provided chip IC's gain increased little.
Tuner
Filter
High Gain chip
Fig.30 Configuration without Amplifier Compensation Insertion Loss
Tuner
Filter
High Gain chip
High impedance type
Tuner
Filter
High Gain chip
impedance type
Fig.31
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Appendix
5-1. Detection Methods Specification Surface Acoustic Wave Filter
There detection methods chip VIF, which shown Fig.32 (b). Both methods adopt (Low Level Detector), synchronous detection method. intercarrier type sound detection video detection performed same detector, they separated. signal divided two, supplied sound detector another supplied video detector through sound carrier trap. there problem 920kHz beat (c-s). increase excessively level sound carrier, that sound carrier attenuation filter should required order 18dB 24dB from peak. other hand, method (b), since sound carrier trap inserted before video detector, there problem 920kHz beat. this case, order increase output sound sound carrier attenuation filter should required have order l0dB 18dB from peak. result there required frequency characteristics filter (especially attenuation sound carrier frequency) depending upon type used (detection method used).
Detector stage Amplifier Input Synchronous Detector Video Output Sound Output Carrier Limit
Sound Carrer Trap
Detector stage Synchronous Detector Video Output Carrier Limit Sound Output Synchronous Detector
Input
Fig.32 Detection Methods
5-2. Direct Breakthrough
Suppose direct breakthrough sufficiently suppressed, there will superposition signals with time delay advance) upon main signal, producing result ghost troubles upon picture television set. TTE, since delay sec. with regard main signal, ghost will appear right side, direct breakthrough, ghost will appear left side sec. advance(*). Whether direct breakthrough suppressed sufficiently observed amplitude characteristics group delay time characteristics stage. other words, direct breakthrough interferences with main signal, result periodic ripples amplitude characteristics group delay time characteristics, suppression direct breakthrough inferred from magnitude ripples. ripple period when caused TTE, 1/Hz when caused direct breakthrough. Thus, imagine roots ripple seeing period ripples. example, case SAFGN58M7VH0Z00B03 approximately 1.0µsec., thus period ripples
Fig.12
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Appendix
approximately 500kHz. High level direct breakthrough makes only ripples group delay time amplitude also trap depths reduction shown Fig.33, with deterioration attenuation level outside pass band. described previously level suppressed less than -40dB increasing power loss value larger than 18dB, means mismatching. other hand, level direct breakthrough influenced printed circuit layout. causes direct breakthrough classified items: Electrostatic causes like stray capacitance, etc. Electromagnetic inductions currents passing through printed pattern residual resistance common ground.
Attenuation (dB) 47.0 52.0 57.0 Frequency (MHz) Frequency characteristics when direct breakthrough sufficiently suppressed 62.0
1800 1600 1400 1200 1000 67.0 Group delay time (nsec.) Group delay time (nsec.)
1800 1600 1400 1200 1000 52.0 57.0 Frequency (MHz) Frequency characteristics when direct breakthrough suppressed 62.0 67.0
With regard electrostatic causes, printed Input/Output patterns should made sufficiently small short, stage including filter etc. should shielded from other stage, many cases, design earth pattern important influence upon direct breakthrough level. conventional filters, every free space printed circuit board filled much possible with earth pattern, which mutually connected wherever possible. However, this configuration suited case filter. This configuration creates many earth path loops, currents passing through these loops often make coupling between input output. same reasons, earth position bypass capacitor amplifier insertion loss compensation must selected with special care. When designing pattern printed circuit, recommendable prepare initially provisional pattern, then some many earth path means method, until minimizing bottom level outside pass band. Fig.34 shows frequency characteristic video detector output when direct breakthrough sufficiently suppressed, when suppression sufficient, respectively. Fig.34 since direct breakthrough sufficiently suppressed, only small ripple with period exists. Fig.34 there superposition double period ripple caused direct breakthrough upon ripple, result large ripple small ripple appear alternatively.
Attenuation (dB) 47.0
Fig.33
Detector Output (DC)
Frequency
Detector Output (DC)
Frequency
Fig.34
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Appendix
5-3. Impedance Surface Acoustic Wave Filter
far, discussions related impedance filter refer equivalent circuit Fig.12 with value resistor capacitor considered constant value. However, values both capacitor resistor present frequency dependence. example, Fig.35 present frequency characteristics Rpi, SAFGN58M7VH0Z00B03. input side (Rpi, Cpi) output side (Rpo, Cpo) present different frequency characteristics difference IDT. While output normal electrode constant overlap constant pitch, input apodized (weighted) one. measurement result input impedance SAFGN58M7VH0Z00B03 including series tuning coil plotted Smith chart shown dotted line Fig.37 (Since SAFGN58M7VH0Z00B03 high impedance type filter, tuned series order lower impedance around 75). purpose reducing return loss mismatching remarkable change frequency characteristic direct connection tuner output filter, necessary minimize variation impedance filter including matching network from action adding resistor shown Fig.38 which effective adjust input impedance filter constant. Solid line Fig.37 shows impedance characteristic when resistor added variation from become small. However, this case, power consumed attached resistor increases loss. have said 4-1-2 that problem that tuner output impedance varies much with frequencies case direct connection tuner filter. connection easily made impedance filter adjusted constant means this method.
15.0 15.0
10.0
10.0 (pF)
52.0
54.0
56.0
58.0
60.0
62.0
Frequency (MHz)
Fig.35
15.0
15.0
10.0
10.0 (pF)
52.0
54.0
56.0
58.0
60.0
62.0
Frequency (MHz)
Fig.36
R/Z0
R=1.5k
Z0=75
Fig.37
P06E3.pdf 01.10.24
Appendix
When impedance adjusted adding resistance, shown Fig.38 (a), (b), (c), there additional advantage, which damping frequency dependence radiation resistance (RS), same time disadvantage, which increase loss. transformation impedance without increase power loss performed shown Fig.39 (b), damping radiation resistance variation expected.
Fig.38 Impedance Adjustment Means Resistor
Fig.39
P06E3.pdf 01.10.24
Appendix
5-4. Reliability Test
Surface acoustic wave filter should used carefully exceed maximum rating shown Table below. Murata performs periodic reliability tests filter. conditions them shown Table data SAFGN58M7VH0Z00B03 shown Fig.40, which shows that variation small enough compared limit. (Table
Test Items Vabration Drop Lead Pull Lead Bend Heat Resistivity Melt Solder Soldering Humidity Test Thermal Stress Test Test Conditions 3300 r.p.m. Amplitude (P.P.) 1.5mm X,Y,Z directions, each 100cm, times seconds 0.3kg, return 260°C, seconds 230°C 5sec. covered with solder more than lead 60°C, hours, -55°C min. min. cycles 85°C, hours -40°C, 500hours
Items Voltage Pulse Voltage Input Signal Voltage Operating Temperature Storage Temperature Maximum Rating 150V/200pF 5Vp-p +60°C. +85°C.
High Temperature Test Temperature Test
Table Reliability Test Conditions
Insertion Loss Variation Variation Variation Variation ±1.5dB max. ±1dB max. ±1dB max. ±1.5dB max.
Table Maximum Ratings
Table Limit
Humidity Test 60°C +0.5 loss (dB)
High Temperature Test 85°C
Pressure Cooker Test 120°C
Thermal Stress Test -55°C +85°C
-0.5
1000 (hrs.)
1000 (hrs.)
(hrs.)
(cycle)
+0.5 (dB) (dB) (dB)
-0.5
+0.5
-0.5
+0.5
-0.5
Fig.40 Reliability Test Result SAFGN58M7VH0Z00B03
P06E3.pdf 01.10.24
Appendix
5-5. Notice (handling)
characteristics vary filter without cutting voltage. static high voltage applied between input terminals output terminals, filter destroyed. characteristics vary lead contact with heated soldering iron long time. filter direction opposite input mark makes frequency characteristics disgraded.
P06E3.pdf 01.10.24
Note:
Export Control customers outside Japan Murata products should used sold development, production, stockpiling utilization conventional weapons mass-destructive weapons (nuclear weapons, chemical biological weapons, missiles), other weapons. customers Japan products which controlled items subject "Foreign Exchange Foreign Trade Law" Japan, export license specified required export.
Please contact sales representatives product engineers before using products listed this catalog applications listed below which require especially high reliability prevention defects which might directly cause damage third party's life, body property, when intending products other applications than specified this catalog. Aircraft equipment Aerospace equipment Undersea equipment Power plant equipment Medical equipment Transportation equipment (vehicles, trains, ships, etc.) Traffic signal equipment Disaster prevention crime prevention equipment Data-processing equipment Application similar complexity and/or reliability requirements applications listed above Product specifications this catalog August 2001. They subject change products discontinued without advance notice. Please check with sales representatives product engineers before your ordering. there questions, please contact sales representatives product engineers. parts numbers specifications listed this catalog information only. requested approve product specification transact approval sheet product specification, before your ordering. Please note that unless otherwise specified, shall assume responsibility whatsoever conflict dispute that occur connection with effect and/or third party's intellectual property rights other related rights consideration your using products and/or information described contained catalogs. this connection, representation shall made effect that third parties authorized rights mentioned above under licenses without consent. None ozone depleting substances (ODS) under Montreal Protocol used manufacturing process
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Cat. P06E-3
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