cerafil app manual

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CERA M IC FILTER (CERA FIL

)APPLICATION MANUAL

MurataManufacturing Co., Ltd.

Please read CAUTION and Notice in this catalog for safety. This catalog has only typical specifications. Therefore you are requestedto approve our product specification or to transact the approval sheet for product specification, before your ordering.

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Introduction

Cera mic filters (CE RAFIL *) ha ve now become an

indispensable component in n umerous electric

equipments.

The IC, ha ving developed in milita ry a nd spa ce

a pplications, ha s found wide use in t he field ofcommercial equipment , such a s st ereo systems, TV sets,

Automotive radios, etc. For this rea son, new miniat ure

integrated filters, with high performance, are extremely

desira ble for use in IF circuits.

Moreover, radio wave disturbance due to remarkable

sophisticat ion of communication netw ork and ra pid

progress of dat a tra nsmitt ing ra te ha ve become

significa nt problems. As a r esult, the dema nd for filters

with high selectivi ty an d wide pass ban d width ha s

increased.

The IC application of the a ctive elements w ill continu e

its progress, and t here wil l be a growing demand forhighly selective, non-a djusta ble, minia tur e and w ide

pass band w idth IF circuit .

Under such circumstances, CERAFIL f i ts in a broad

ra nge of products a s the most suita ble component.

However, w hen one comes to th e application of

CERAFIL , one finds very litt le reference litera tur e on

application and design features. This CERAFIL

Application Ma nua l ha s been compiled to help you

design with the superior characteristics of CERAFIL ,

to utilize them more effectively an d wit hout an y

problem. The edition explains the CE RAFIL principle,

the feat ures a nd th e specific criteria for th e applica tionof CE RAFIL .

We intend t o assist y ou utilize all of these feat ures

effectively by ma tching th e purpose and the a pplication.

*CERAFIL is the bra nd n a me of the MU RATA product.


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1 Types of CERAFIL

2 Filter

3Operating Principle ofCERAFIL

4 Tecnical terms of CERAFIL

5 Discriminator

6 Trap

7 Features for CERAFIL

8 How to Use CERAFIL

9Ceramic DiscriminatorApplication

10 Appendix

CONTENTSTypes of CERAFIL YYYYYYYYYYYYYYYYYYYYYYYYYYY12

FilterYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY13

1. Filter ..............................................................................................03

2. Operating Principles and Features of Filters ............................03

Operating Principle of CERAFILYYYYYYYYYYYY

141. What is Piezoelectric Effect? ......................................................04

2. What is Piezoelectric Ceramics?................................................05

3. Electrical-Mechanical Transducerand its Equivalent Circuit ...........................................................05

1. Vibrating Mode ............................................................................05

2. Symbols in the Electrical Circuit of the Electrical-Mechanical

Transducer and the Equivalent Circuit........................................06

4. CERAFIL......................................................................................07

Tecnical terms of CERAFIL YYYYYYYYYYYYYYYYY18

1. Frequency Characteristics of CERAFIL

and the Related Terminologies...................................................08

2. Other Terminologies....................................................................09

1. Input/Output Impedance .............................................................09

2. Impedance Matching...................................................................09

3. dB (Decibel) ................................................................................09

4. dB..............................................................................................10

5. Group Delay Time Characteristic ................................................10

Discriminator YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY11

1. Discriminator ...............................................................................11

2. Detection methods......................................................................12

1. Ratio detection ............................................................................12

2. Quadrature Detection..................................................................13

3. Differential Peak Detection .........................................................13

Trap YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY14

1. Trap ...............................................................................................14

2. Ceramic Trap ................................................................................14

1. Two-Terminal Ceramic Trap .......................................................14

2. Three-Terminal Ceramic Trap .....................................................15

Features for CERAFILYYYYYYYYYYYYYYYYYYYYYYY16

1. Designing with a high-selectivity is easy ..................................16

2. No Peaking Needed .....................................................................16

3. A Very Suitable Component for Miniaturization........................16

4. A Very Suitable Component for Integrated Filter......................16

5. Optimum Component for Solid State Application ....................16

How to Use CERAFILYYYYYYYYYYYYYYYYYYYYYYYY17

1. Impedance Matching ...................................................................17

2. Countermeasure for Spurious Response..................................18

3. Consideration for Gain Distribution ...........................................18

4. Bias Circuit ...................................................................................19

Ceramic Discriminator ApplicationYYYYYYYYYY20

Appendix YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY22

1. Correct Use of Ceramic Discriminator .......................................22

2. Applied IC Reference Table for Ceramic Discriminator ...........22

1

2

3

4

5

6

7

8

9

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2

1 Types of CERAFIL

1

Types of CERAFIL and applicable markets

Types of CERAFIL

CeramicFilter

CeramicDiscrim

inator

CeramicTrap

Typical CenterFrequency

450kHz455kHz

K K K K K K K K

K K K K K K K

K K K K K K K K

K K K K K K K

K

K K K

K K K K K

K

10.7MHz

4.5MHz5.5MHz

6.0MHz6.5MHz

450kHz455kHz

10.7MHz

4.5MHz5.5MHz

6.0MHz6.5MHz

Hi-FiAudio

RadioCommunica

tion

Equipment

CodeLessPhon

e

MobilePhone

WireLessData

communication

RKE/TPMS

TV/VCR

CarAudio

PortableAudio

SMD Type

Lead Type

SMD Type

Lead Type


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2 Filter

1. Filter

An electrica l component wh ich has a function of passing

(or st opping) a specific freq uency.

2. Operating Principles and Features of Filters

The filters ha ve different n am es depending on the

structures an d th e mat erials used. The types, the

principles and t he featur es of the filters which ar e

currently used a re shown in the t able 1.

Fig.2-1 graphically show s the rela tions between the

applicable frequency range a nd th e band w idth of each

filter.

!Table 1. Operating Principle and feature of each filter.

Active Filter

Mechanical Filter

Crystal Filter

Ceramic Filter

LCFilter

100

10

1

10

10

10

-1

-2

-3

100 1k 10k 100k 1M 10M 100M 1G

Frequency(Hz)

FractionalBandWidth

(%)

Filter Groups

The Range of

ApplicableFrequency

Function Operating Principle Feature

10kHz

to 100MHz

B.P.

B.E.

Utilizing a piezo-electrical ceramics as anelectrical-mechanical transducer and as a

mechanical resonator, a specific characteristic isobtained by simultaneously providing electricaland mechanical system within a single system.

The dimensions are smaller than the LC filter. Thefrequency is fixed for both IF circuit and FM detectorcircuit, and high selectivity is obtained. The

frequency stability is inferior to the crystal filter. It hassome spurious response by mechanical vibration.

Ceramic Filter

100Hzto 150MHz

L.P.

H.P.B.P.B.E.

A specific characteristic is obtained by merging the

positive and negative reactances of the coil (L) andthe capacitor (C).

The acceptable degree of vibration for choosing thecenter frequency, the pass band, the amplitudecharacteristic or delay characteristic is normally

great. On the other hand, the dimensions are oftenlarger compared with the vibrating type of filter and

the shape factor is inferior.

LC Filter

3kHzto 200MHz

L.P.

H.P.B.P.B.E.

A specific characteristic is obtained by merging

both series and parallel resonant frequency byusing frequency characteristics near the resonantpoint of the crystal resonator.

The loss is extremely small, the cut-off characteristic

is very steep and the stability is great. It is hard to getthe wide band because of a high Q.

Crystal Filter

100Hzto 800kHz

B.P.

It consists of 3 portions of mechanically vibrating

filter sections which have certain frequencycharacteristics. The mechanical electrical

transducer section and the matching section whichconnects with the external electronic circuit. It

converts energy by adhering the piezo-electricceramics on the metallic resonant element.

The loss is small, the cut-off characteristic is steepand the stability is great. The structure is rather

complicated. It also has a spurious characteristic.The dimensions are large.

Mechanical

Filter

100Hzto 80kHz

L.P.H.P.B.P.

B.E.

Although the operating principle differs by the type,each of them generally utilizes the characteristics

of the OP-Amp., and it operates the circuit bycorresponding the merging circuit of both the OP-

Amp. And the RC to the transfer function. A hybridIC is used because a respectively high accuracy is

required for the RC.

The characteristics of any filters are available withthis type. Compared with both the LC and

mechanical filter, a miniature and light-weight filter isavailable in the low frequency range. It has strong

vibration and shock resistance. It requires the power

source.

Active Filter

L.P. : Low Pass Filter, B.P. : Band Pass Filter, H.P. : High Pass Filter, B.E. : Band Eliminate Filter

Fig. 2-1 The relations between the Applicable FrequencyRange and the Band Width of Each Filter Type

2


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CERAFIL (cera mic filter) is a filter w hich uses a

piezoelectric ceramics (bar ium tit a na te ceramics, lead-

zircona te-tita na te cera mics, etc.) a s an electrical-mechan ical tr an sducer and a s a mechanical resona tor.

It provides simultaneously the electrical and the

mechan ical system with in a single element.

1. What is Piezoelectric Effect?

Distort ion ta kes place in the crystal la t t ice when a

stress is a pplied upon it, an d the crysta l group wh ich

ha s no symmetric center in the crysta l groups causes a

polarization in addition to the distortion.

This phenomenon w a s found by the C urie brothers in1880 a nd is called t he piezoelectr ic direct effect (or

Curies Effect). In other wa rds, i t means t ha t t he

mechanical force (stress) can be converted int o an

electrica l signa l (an electrical field) or t he electrica l

signa l into t he mechan ical force. These tw o phenomena

a re collectively called t he piezoelectric effect, a nd a ny

substance which ha s this na ture is cal led the

piezoelectric ceram ics.

The crysta l group, the symmet ry of wh ich is inferior

among a l l crysta ls having the chara cterist ic of the

piezoelectricity, ha s a na tive limited volume of

polar izat ion before some electric field or st ress isa pplied. This is called sponta neous polar izat ion. The

crysta l is distorted by a phenomenon like the th erma l

vibration of atoms according to the temperature change.

The degree of the sponta neous polar izat ion also chang es

according to the distort ion of crysta l a nd i ts varia t ion

a ppear s a s a potentia l difference. This is called the

phenomenon of pyroelectricity.

On the other hand, w hen such a crystal is applied with

a n electr ic field, a dist ortion or a str ess occurs. It is

called the piezoelectric inverse effect (or Lippmans

Effect).

Also among the crystals which have a spontaneous

polar izat ion, those which can r everse its direction by the

externa l electrica l field ar e called ferroelectric

substa nce. The relat ions among th ese effects ma y be

expressed a s Fig . 3-1.

Fig. 3-1 Relations Among Piezoelectricity, Plroelectricity,and Ferroelectricity.

Dielectrics

Piezoelectricity

Pyroelectricity

Ferroelectricity

3 Operating Principle of CERAFIL

3


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3. Electrical-Mechanical Transducer and its Equivalent Circuit

1. Vibrating ModeSince the ceramic resonator with which the polarization

ha s been oriented is piezoelectric, a s described earlier, it

vibra tes in a vibra t ing mode when the electrodes are

provided with t he cera mic resona tor, a sine wa ve is

a pplied across the both polar ities an d then excited.

Ta ble 2 shows th e typical vibrat ing modes, the sha pes

a nd t he a pplicable frequencies of such ceramic

resonators.

!Table 2. The Vibrating Modes and the ApplicableFrequency Band

Frequency

Vibrating mode (Hz)

Flexural

mode

Lengthmode

Area

expansion

mode

Thicknessshear

mode

Thicknessexpander

mode

1k 10k 100k 1M 10M 100M 1G

Note : Arrows signifies the directions of the vibrations.

Operating Principle of CERAFIL 3

2. What is Piezoelectric Ceramics?

Some of the piezoelectric cryst al can be calcined int o the

polycrysta l cera mics, though th ere is a sponta neous

polar izat ion in each of the fine cryst a ls in the

piezoelectric ceramics wh ich is cancelled a s a wh ole and

shows no piezoelectricity. B ut w hen a high D .C. volta ge

is a pplied t o such ceram ics, the directions of the

spontaneous polarizations are brought to an uniformity

a nd a ferr oelectricity ceramics is att a ined. With some

addit ives, the ma terial w ith extremely sta ble frequency,

tempera ture a nd a ging chara cterist ics is being used by

MU RATA for CE RAFIL . Compared w ith t he single

crysta l, the piezoelectric cera mics has va rious

adva nta geous features a s fol lows ;

1. Can be mass-produced a t low cost.

2. Ca n be formed into any desira ble sha pe.

3. The direction of the polar izat ion is ea sily at ta ina ble.

4. Chemically and physically stable.

5. Easy for fabrication.

3


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3 Operating Principle of CERAFIL

3

In an ideal electrical-mechanical transducer, the

impedance change t a kes place as shown in Fig. 3-5, a nd

each consta nt of these and each consta nt of the

equivalent circuit in Fig. 3-3 are in the following

relat ion of equa tions shown in Fig. 3-5.

Fig. 3-5 Impedance Characteristic of the 2-terminal Type

Za

Zr

fr

Frequency

fa

fr

fa

Zr

Za

: Resonant Frequency

: Anti-Resonant Frequency

: Resonant Impedance

: Anti-Resonant Impedance

fr=1

2 L1 C1

fa=1

2 L1 C1 C0

C0+C1

Fig. 3-3 Two-terminal Type Equivalent Circuit

C1

C1

L1

R1

C0

: Equivalent Compliance

: Equivalent Mass

: Equivalent Resistance

: Parallel Equivalent Capacity

L1 R1

C0

Fig. 3-4 Relations Between Spring-Pendulum andElectrical-Mechanical Transducer

Mass M.=.L1

SpringConstant.=.1/C1

Wall

Floor

FrictionResistance.=.R1

Weight

2. Symbols in the Electrical Circuit of theElectrical-Mechanical Transducer and the

Equivalent CircuitThe symbols as shown in Fig. 3-2 are us ed for theelectrica l-mechanical t ra nsducer in a n electrica l circuit.

The equivalent circuit w ith t wo-termina l type

tra nsducer near the resona ting point is shown in Fig. 3-3

even if the vibra ting mode used is different. E a ch

par am eters can be considered a s spring-pendulum

show n in Fig. 3-4.

C 0 : the capa citan ce between th e electrodes is ca lled the

para l lel equivalent capacita nce.

C 1 : mechanica lly corresponds to t he flexibility of rubber

or a spring, and i t is cal led the equivalentcompliance.

L1 : mecha nically corresponds to the inert ia (mas s or

moment) a nd is called the equiva lent ma ss (or

equivalent inductance).

R1 : is a friction resista nce, a nd is called the equivalent

resistance.

Fig. 3-2 Symbols in the Electrical Circuit for the Transducer

Two-terminal Transducer Three-terminal Transducer


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4. CERAFIL

When t he piezoelectric cera mics described a bove is

polar ized by providing a pa ir of electrodes so tha t it ca n

be excited in a prescribed vibrat ing mode and if a

suita ble matching impeda nce is a pplied to operat e it, a

CERAFIL is completed. A model exam ple of 455 kHz

CERAFIL for AM is shown in F ig. 3-6.

Fig.3-6 Mod el of t he 455 kHz CERAFIL for AM

(Ceramics)

Ground

Input (Driving Electrode) Output (Pick-up Electrode)

Operating Principle of CERAFIL 3

3


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4

Frequency

0

3

20

[dB]

Input Level

(or6)

(or40)

q

e

r

t

y

w

u

i

A

ttenuation

Some specific terms ar e used with C ER AFIL . Let us

explain those terms in this pa ra graph.

1. Frequency Characteristics of CERAFIL and the Related Terminologies

Refer to the freq uency chara cteristic gra ph (Fig. 4-1)

wit h pa rticula rs (Ta ble 3).

Fig. 4-1 An example of CERAFIL frequency characteristic

Numbers in Fig.4-1 Terminology Symbol Unit Explanation of the Term

Center Frequency f0 HzIt signifies the frequency in the center of the pass band width. However, the center

frequency for some product is expressed at the point where the loss is minimum.q

Pass Band Width(3dB)

B.W.Hz

Signifies a difference between the two frequencies where the attenuation becomes 3dB

from the level of the minimum loss point.w

Insertion Loss Loss dB

Expressed in the input and output level ratio at the point of minimum loss in dB. (The

insertion loss for some product is expressed in the input and output level ratio at the

center frequency.)

e

Ripple dB

If there are peaks and valleys in a pass band width, the ripple expressed the level

difference of voltage between the maximum peak and minimum valley and it is

expressed in dB.

r

Attenuation Band Width

(dB band width)

(20dB)

B.W.Hz

Signifies a difference between the two frequencies where the attenuation becomes the

specified values (dB) from the level of minimum loss.

(Example: Expressed at a point where the attenuation becomes 20 dB in case of 10.7

MHz filter.)

t

Selectivity dB

Expressed as the attenuation of the detuning point from the center frequency.

(Example: The attenuation that 9 kHz was detuned from the center frequency in case

of 455 kHz filter.)

y

Spurious Response sp dB

Expressed as the difference of voltage ratio between minimum attenuation point in the

stop band range and minimum loss point in the pass band width by using dB (The

stopped range is specified with each filter).

u

Spurious Signifies the frequency response based on the parasitic (unwanted) vibration against

the frequency except the fundamental vibration.i

Bottom Level dBSignifies the minimum or average attenuation without both main response and spurious

within the specified frequency range.

Shape Factor

One of the ways expressing the selectivity, which is expressed as [Attenuation Band

Width/Pass Band Width]. The selectivity becomes steeper as the resultant value comes

closer to value 1.

Other

!Table 3. Terminologies



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2. Other Terminologies

1. Input/Output ImpedanceSignifies the internal impedance value of the input and

output side at t he center frequency of CE RAFIL , and i t

is expressed in . It causes no problem even if the input

and the output a re used in reverse with CERAFIL ,

since the input a nd th e output impedance are in a

symmetry of substa ntia l ly almost same value.

2. Impedance MatchingWhen connecting one electric circuit to another, or a

component to another, or one electric circuit to a

component, the electric energy is supplied mostefficiently from th e signa l source to the load if th e signal

source impedance and t he loa d impedance are sa me. If

these impedan ces a re misma tched, electric energy

esca pes in form of a reflection. To mat ch the signa l

source impedance and the load impeda nce is called the

impedance ma tching. This is very importa nt for

CERAFIL , as an improper impedance matching may

cause va rious troubles (refer to the a dvised points in

chapter 8-1).

3. dB (Decibel)

Decibel is the loga rith mic rat io va lue by comparing t hetwo levels. I t is a lso used with C ERAFIL when

expressing th e frequency cha ra cteristics, the insertion

loss, the spurious response, etc.

dB is defined a nd calculat ed by the rat io of the electric

power, th e volta ge and t he current , as follows:

Electric Power Ra tio dB = 10log10P 2/P 1

(electric power a t t wo points a s P 1 and P 2)

Volta ge Rat io dB = 20log10E 2/E 1

(voltage a t t wo points a s E 1 and E 2)

Current Ra tio dB = 20log10I2/I 1

(current a t t wo points a s I1

and I2

)

The merit of using the decibel:

(1) As exemplified a bove, the d ecibel is express ed in

logari thm.

(2) The a mplitude, a tt enua tion, etc. ar e simply

calculated by merely a dding, or subtra cting.

4

4Tecnical terms of CERAFIL


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4

4. dBThe dB ha s been used only for compar ing th e two

volumes such as the electric power ra tio, volta ge ra tio,current ra tio, etc. Besides dB ma y be also used for

expressing t he electric power or volta ge by deciding on

some reference values. In CE RAFIL , dB is used for

expressing voltage va lue such a s the input level. Here

the reference value is 0 dB = 1 V. In other w ords, the

volume tha t represents a level of 60 dB equa ls 1 mV. It

is important to clearly distinguish dB from dB.

The decibel for expressing other levels:

dB m : The voltage or current level to obta in th e power of

1 mV in th e load of 600 is specified a 0 dB m.

(Volta ge : 0 dB m = = 0.775 Vrms)

dB s : Reference values is 1 Vrms = 0 dBsw

5. Group Delay Time CharacteristicOne of the most importa nt cha ra cteristics of a

tra nsmitt ing element is to tra nsmit a signal with th e

lowest distort ion. This dist ortion occurs wh en th e phase

shift ing of a signa l which passes through a certa in

tra nsmitt ing pat h is nonlinear to the frequency. For

convenience the G DT chara cteristic is used for the

purpose of expressing th e non-linearit y a ga inst t hefrequency of phase shifting a nd it is calculated by th e

followin g formu la : TD (G DT), , (phase difference

between input a nd output) and (an gula r frequency).

Above formula shows th at the pha se slope was

differentiated by t he frequency. Tha t is to say, when t he

GD T is consta nt , a signal is tra nsmitted correctly

without distort ion.

Recent trends in quality FM receiver and other

equipment emphasizing the distortion factor

chara cterist ic are a lso stressing the phase l ineari ty inthe pass band. In other word, they need a flat GD T

Cha racterist ic with high selectivi ty.

In principle the G DT chara cterist ic and the a mplitude

chara cteristic rela ted each other. The amplitud e

chara cterist ic with a flat top is cal led the Butt erworth

Cha racterist ic, while the a mplitude chara cterist ic

resembling a sign wa ve is cal led a G aussia n

Cha ra cteristic as shown in F ig. 4-2.

Fig. 4-2 Relationship between Amplitude andGDT Characteristic

Attenuation

Attenuation

Frequency Frequency

AmplitudeCharacteristic

AmplitudeCharacteristic

GDT

Characteristic

GDT

Characteristic

(b) GaussianCharacteristic(a) ButterworthCharacteristic

600110-3

TD =d

d



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5 Discriminator

In t he preceding cla use, they ar e an explana tion for

filter chara cteristic and it s principle. We have ceramic

discriminat ors which convert the changes in frequencyinto an audio signal via the va rious detection methods

based on impedance or pha se cha ra cteristics of

CERAFIL .

1. Discriminator

The detection of FM wa ve is mad e through t he circuit in

which the relat ion between the frequency a nd th e

output voltag e is linear. The discriminat or functions t o

convert t he change of the frequency into audio

frequency, an unique syst em of detection only used for

FM broadcasting. FM wave detection methods, such as

ra tio detection, Foster-Seeley detection, qua dra tur e

detection, differentia l peak detection, etc. ar e known.

5


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5

5 Discriminator

2. Detection methods

1. Ratio detectionRa tio detection is the most popular m ethod in use at

present. Let us intr oduce its simple opera ting principle

a s show n in F ig. 5-1. The volta ge e1 and e2 applied to

the diode D 1 and D 2 a re composed of both the prima ry

volta ge V1 and a hal f of the secondary voltage V2. The

volta ge e1 and e2 ar e expressed in the equat ions a s

shown in F ig. 5-1 (b). B y t his high frequency volta ge,

the rectified current l1 of diode D1 ha s voltage E 1

genera ted a t both ends of C3, and voltage E 2 as w ell as

E 1 occurs a t both end s of C4. Moreover, th e voltage of

both ends of R3 and R4 becomes (E 1+ E 2)/2 si nce the

voltage (E 1+ E 2) ta kes place at both ends of R3 and R4 by

the current l1 and l2.

We will consider t he tun ing frequency of discriminat or

as fo and the input frequency as f .

(1) For f= fo, E0 becomes zero owin g t o E1= E 2

(2) For f


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3. Differential Peak DetectionThis detection method w a s developed by RCA as a

sound detector for TV sets. The method has following

features.

(1) Ca n output lar ge level.

(2) Can function with only 1 synchronous coil.

The prin ciple is shown in F ig. 5-3. The circuit r esona tes

f1 at point B a nd f2 a t point A due to own impedance

change.

Non-linearit ies of synchronous cha ra cteristics ar e

compensat ed each other by a pplying rectified

intermedia te frequency volta ge. As the results, linearit y

like line a shown in Fig. 5-3 ca n be obtain ed.

Fig. 5-3 Differential Peak Detector

Vcc

(a) Schematic

A B

C D

(b) S-Curve

f1

V

a

f2 f

2. Quadrature DetectionThis detection method w a s origina lly developed as a

sound detector for TV sets, but r ecently it ha s becomepopular in t he consumer mar ket (FM tun ers, ca r ra dios,

etc.). The fund am enta l circuit composition is illustra ted

in F ig. 5-2 (a ) and th e opera tin g prin ciple in Fig. 5-2 (b)

a nd (c). This detection method ut ilizes the pha se

chara cteristic. An FM sign a l is supplied directly to one

side of the multipliers input w ith a n IC to the other side

of the multipliers input a n FM-IF signa l, which is

passed through th e phase shift ing circuit ma inly

composed of a ta nk circuit tuned to FM-IF, is a pplied.

According t o the pha se difference betw een e1 and e2

(passed t hrough t he pha se shifter). As shown in Fig. 5-2

(b) a nd (c), th e pulse wid th of out put iL

changes, and bypassing i t through the low pass fi l ter the average va lue

of the output -pulse cha nges a nd t he pha se detection is

performed. U p to this time a coil ha s been used a s a

phase shifter. Again, by ta king adva nta ge of the phase

characteristic of the ceramic resonator as a ceramic

discriminator, we can el iminat e adjustment of the FM-

IF circuit.

5Discriminator

5

Fig. 5-2 Quadrature Detector

Phase

Shift Circuit

Multiplier Low-pass

Filter

AudioAmp.

Output

Input

LimitingAmp.

(a)BlockDiagram

eo

ei

Input

iL

RL

i4

i3

e2

e1

i1i2

is

I0

Vcc

Vout

(b) Schematic

PhaseShiftCircuit

e1

i1 i2 i1 i2 i1 i2 i1

i4 is i4 is i4 is

i1

i2

e2

iL

+

0

+

0

0

0

(c) Wavesof each part

Iav


16/2714


P11E.pdf 02.10.30

6

6 Trap

1.Trap

As ment ioned a bove, cera mic filter pass es only

part icular frequency. To the contrary, B an d E liminat e

Filter (B. E. F.) wh ich blocks or a tt enua tes par ticular

frequency is called tr a p. Sound tr a p for TV set is one of

the fa mous exa mple of B. E . F.

In TV set, video signal is used in pictur e am plitude

circuit a fter video signa l detection block, cera mic

resonat or is insert here a nd tr a p circuit is formed in

order to elimina te sound signa l involved in video signa l.

2. Ceramic Trap

Cera mic tra p is divided into 2 types as mentioned

below.

1.Two-Terminal Ceramic TrapA 4.5 MH z resona tor (TP SR D4M50J 00-B 0) is inser ted

in para l lel with sta ndar d signal generator (S. S . G.) as

shown in Fig. 6-1 and block 4.5 MHz signa l wh ile

leading it to eart h side. Fig. 6-2 shows t he signa l at 4.5

MHz is at tenuat ed around 30 dB from 0 Hz point tha t is

rega rded a s 0 dB. Two-termina l cera mic discrimina tor is

used in B lack a nd White TV sets since the number ofperiphera l components can be reduced, th ough its

at tenuat ion isn t so much.

Fig. 6-1 Measurement Circuit Diagram ofTwo-Terminal Ceramic Trap

75

50

Rg=50

S.S.G

1k RF

Voltage MeterCeramicTrap

Fig. 6-2 Frequency Characteristic ofTwo-Terminal Ceramic Trap

TPSRD4M50J00-B0

0

10

20

30

40

50

60

70

0 1 2 3 4 5 6 7 8 9 10

Attenuation

(dB)

Frequency(MHz)


17/2715


P11E.pdf 02.10.30

2.Three-Terminal Ceramic TrapThree-termina l cera mic tra p has a monolith str ucture

formed from 2 ceramic resona tors. F ig. 6-3 shows ameasu rement circuit of three-termina l cera mic tr ap

(TP SRA4M50C00-B 0) tha t is inserted in pa ra llel with S.

S. G . The cha ra cteristic of a th ree-termina l cera mic tra p

equals t wo tw o-terminal cera mic trap.

Three-termina l ceram ic tra p att enuat es the signal at 4.5

MHz a round 50 dB from 0 Hz point sh own a s Fig. 6-4.

Though thr ee-termina l cera mic tra p needs a dditiona l

coil shown a s Fig . 6-3, it is used in C olor TV set a nd

VCR due to i ts high a t tenua tion.

Fig. 6-3 Measurement Circuit Diagram ofThree-Terminal Ceramic Trap

220

50

Rg=50

S.S.G

R RF

Voltage MeterCeramicTrap

L

Fig. 6-4 Frequency Characteristic of Three-TerminalCeramic Trap

TPSRA4M50C00-B0

0

10

20

30

40

50

60

70

0 1 2 3 4 5 6 7 8 9 10

Attenuation(

dB)

Frequency(MHz)

6Trap

6


18/2716


P11E.pdf 02.10.30

7

7 Features for CERAFIL

1. Designing with a high-selectivity is easy

By virtue of employing a mecha nical vibra t ion means,

CERAFIL ha s a high Q compared w ith IFT, and

therefore, a h igh selectivity is obtain ed. J ust one

CERAFIL equals th e selectivi ty wh ich is a vai lable with

2 or 3 IFTs. It a lso has a rema rka ble frequency

tempera tur e coefficient, high selectivity a nd high

stabi l i ty.

2. No Peaking Needed

Because of the fact tha t CE RAFIL is employing a

mechanical resona nce, it is almost una ffected by thesurrounding circuits, and it s cha ra cteristics do not

deviat e when i t is implant ed in the printed circuit a nd

no adjustment is required.

3. A Very Suitable Component for Miniaturization

CERAFIL ha s var ious form in order to apply man y

kinds of a pplicaions.

CERAFIL will support y ou to rea lize spa ce sa ving an d

low profile in your products.

4. A Very Suitable Component for Integrated Filter

There is a growing n eed for int egra ting t he selective

elements because th e gain per sta ge is greater w hen IC

is used in the a mplifier. When building the int egra ted

filter by LC, a t least 5 to 8 stages w ill be required

depending on the selectivity, a nd consequent ly, a la rge

size integrat ed LC fi l ter wil l be required a nd th e

a djustments become extremely complica ted w hen

talking into consideration such factors as the

adjustments for each stage, dispersions and

temperature characteristics. In this respect, CERAFIL

can ea sily be integra ted in compact form a nd for simple

high selectivity.

5. Optimum Component for Solid State Application

Nowa da ys, the electronics sha ll be represented by the

IC, a nd dea ls with t he electrons in th e solid-sta te,

head ing in t he direction of the solid-sta te a pplication

where the functions cannot be separa ted.

CERAFIL utilizes the electrons in the piezo-electric

cera mics, and un like the conventiona l IFT, it cann ot be

dismembered into each fra gment like coil or capa citor. Itis, therefore, most suita ble in IC circuit an d w ill become

popular with I C growth.


19/2717


P11E.pdf 02.10.30


1. Impedance Matching

It is impera tive to mat ch the impedance properly

wh enever any circuit is connected t o other circuit, a ny

component to a nother component or a ny circuit to other

component.

This is a lso the basic requirement for CER AFIL . Thechara cterist ics a s described in the cata log a re a pplicable

a s long a s proper impeda nce ma tching is met.

Impedance matching required for CE RAFIL is not

difficult sin ce the resista nce values giving proper

input /output im peda nce for optimum fr equen cy

chara cterist ics a re shown in our cat alog or

specifica tions. One only ha s to mat ch the signa l source

impedance and the load impeda nce, so the values meet

the ones specified.

Fig. 8-1 shows t he cha nges of the fr equency

chara cterist ics w ith chan ges of the resistance values

with SFECS10M7HA00-R0.If t he input /output impeda nce (R1) and (R2) a re

connected to lower va lues tha n t hose specified, the

center frequency shifts towa rd t he low side a nd th e

ripples increase a s shown F ig. 8-1. On th e other h a nd, if

(R1) and (R2) a re connected to higher values th a n th ose

specified, the center frequency shifts t owa rd th e high

side and t he ripples increa se as shown.

However, the char acterist ic shift caused by t he

misma tching is n ot such a serious problem. The

ma tching impeda nce ca n be wit hin t he ra nge of + /-50%

of the values specified, though the a ccura cy for th e

impedance mat ching depends on the requiredperformance of the model.

As mentioned earlier, CE RAFIL abounds with ma ny

features in comparison with the IF T, but t here are

points of caut ion t o be observed in th e use of CERAFIL

.Let us expla in th ese points h ere. The CE RAFIL must

be thoroughly understood, and when used a t i ts

optimum performa nce, it operat es with out problems.

Fig. 8-1 SFECS10M7HA00 Impedance Characteristic(Input & Output resistive termination)

0

10

20

30

40

10.4 10.5 10.6 10.7 10.8 10.9 11.0

Attenuation

(dB)

Frequency(MHz)

R1+Rg=R2=150

R1+Rg=R2=200

R1+Rg=R2=330R1+Rg=R2=470

R1+Rg=R2=680

R1

Rg

R2

Test Circuit

S.S.G

RF

Voltmeter

8


20/2718


P11E.pdf 02.10.30

8


3. Consideration for Gain Distribution

The impedance of both input a nd output is symmetr ic

a nd sma ll, it is necessa ry to consider the distr ibution in

the circuit. A resister is u sed for the impeda nce

ma tching, a s described in preceding section 8.1. a nd a

certa in D.C. loss is ca used by the resistors, wh ich

reduces the ga in. This sometimes creat es a problem if

the set ha s no a llowa nce for t his loss. The following

countermeasures a re a vai lable.

Countermeasures

(1) U sing CE RAFIL collectively inst ead of using it in

the intersta ge, design the a mplifier sta ge putt ing

stress on the gain.(2) U se in combination w ith IFT for min imizing both

mat ching loss an d D.C. loss. In this case, regard the

IFT merely a s a mat ching tra nsformer an d rely on

CERAFIL for the selectivity.

0

20

40

60

800 2 4 6 8 10

Attenuation(dB)

Frequency(MHz)

2. Countermeasure for Spurious Response

The question of spurious ar ises by the fact th a t t he

resonance occurs under a lien vibrat ing mode or

overtone expect th e basic vibra tion, beca use CE RAFIL

uses mechanical vibrat ion mode. With cera mic filter

such as 10.7 MHz, 4.5 MHz, etc., the spurious is not

grea t enough t o ca use serious problem since these types

use trapped energy vibration mode. But a

countermeasure against the spurious is required for the

455 kHz filt er.

The following countermea sures a re ava ilable.

(1) It is recommenda ble to use supplementa ry I FT

together with C ERAFIL for suppression of spurious.(2) Arranging 2 or more CERAFIL for mutua l

cancellation of spurious.

(3) To provide low pa ss or hig h pa ss filt er of the fixed

LC for suppression of spurious.

Among th e counterm easur es itemized above, the most

common a pproach is meth od (1). The spur ious responses

a re shown in F ig. 8-2 with only S FU LA450KU 2B-B 0

a nd F ig. 8-3 with SF U LA450KU 2B-B 0 + IFT. This

a rra ngement for suppression is enough.

Fig. 8-2 Spurious Response with SFULA450KU2B-B0

0

20

40

60

80

0 2 4 6 8 10

Attenuation

(dB)

Frequency(MHz)

Fig. 8-3 Spurious Response with SFULA450KU2B-B0+IFT


21/2719

8How to Use CERAFIL

8

4. Bias Circuit

Although a bias required to drive the t ra nsistor,

CERAFIL does not pass D .C. This means t ha t t he bias

circuit is required. Bu t since CERAFIL requires,

mat ching resistance, the matching resister can play a

double role a s both ma tching a nd bia s resistor. (Refer to

Fig. 8-4)

In t his case, check the impeda nce of tra nsistors side

from C ERAFIL side, and alw ays ta ke the para l lel

circuit of both the bias resist a nce an d the tr a nsistors

internal resistance into consideration to meet the

resista nce value wit h one of the specifica tion beca use

the internal r esista nce of transistor is cha nged by the

bias resistance.

When using I C, th ere is no need for ad ditiona lly

providing a ny bias circuit since IC ha s a bia s circuit

within i tself . However, considering t hat CERAFIL does

not pass D.C. a nd tha t t he conversion ga in can not be

sufficiently obta ined since the input impeda nce of

CERAFIL is low, th e general a pproa ch is to use IFT

when coupling with MIX stage (Refer to Fig. 8-5).

Fig. 8-4 Coupling with a transistor

Matching

VB

Matching

Bias

VB

Biasand Matching

CeramicFilterdoesnotPassD.C.

D.C.canbesupplied intothetransistorbyaddingaBiasresistor.

TheBiasresistorand theMatchingresistorshallbecommon.

Fig. 8-5 Coupling with MIX stage

OSC.

Mix.

IF

Amp.

IFT

VB

C.F.


P11E.pdf 02.10.30


22/27


23/2721


P11E.pdf 02.10.30

9

!CDSCA10M7GF072-R0Applications : VICS, etc.,

!CDSCA10M7GF107-R0Applications : RKE, TPMS, etc.,

TA31161 Type IC Test Circuit

1 2 3 4 5 6 7 8

16 15 14 13 12 11 10 9

0.01

0.01AF-OUT 820

IF-IN

0.01

0.01

33

+

0.01

4.7

C.D.

10p

Vcc (3.0V)

TA31161(TOSHIBA)

C.D.:Ceramic Discriminator

R:

C:F

L :H

TA31272FN Type IC Test Circuit

1 2 3 4 5 6 7 8 9 10 11 12

24 23 22 21 20 19 18 17 16 15 14 13

AF OUT

R

Vcc(5.0V)

C.D.

S.S.G.

TA31272FN(TOSHIBA)

0.01uF

+

1

00uF

0.

01

uF

0.

01

uF

0.

01

uF

0.

01

uF

1

000pF

0.

01

uF

C.D.:CeramicDiscriminator

R:

C:F

L :H

Recovered Audio Frequency Voltage & Total HarmonicDistortion vs. IF Input Frequency

1000

100

10

1

0.1

100

10

1

0.1

0.01

10.3 10.4 10.5 10.6 10.7 10.8 10.9 1 1. 0 1 1. 1

AFoutputVoltage(mVrms)

T.

H.

D.

(%)

Frequency(MHz)

Output Voltage

T.H.D.

Input =100dBfdev.=40kHz

fmod.=1kHz

Vcc =5.0V

Output D.C. Voltage vs. IF Input Frequency

3.0

2.5

2.0

1.5

1.0

0.5

0.0

Input =100dB

fmod.=1kHz

Vcc =5.0V

1 0. 3 1 0.4 1 0.5 1 0.6 10.7 10.8 10.9 1 1. 0 1 1. 1

Out

putVoltage(V)

Frequency(MHz)

9Ceramic Discriminator Application

Recovered Audio Frequency Voltage & Total HarmonicDistortion vs. IF Input Frequency

1000

100

10

1

0.1

100

10

1

0.1

0.01

10.3 10.4 10.5 10.6 10.7 10.8 10.9 1 1. 0 1 1. 1

AFoutputVoltage(mVrms)

T.

H.

D.

(%)

Frequency(MHz)

Output Voltage

T.H.D.

Input =100dBfdev.=80kHz

fmod.=1kHz

Vcc =3.0V

Output DC Voltage vs. IF Input Frequency

1 0. 3 1 0.4 10.5 10.6 10.7 10.8 10.9 1 1. 0 1 1. 1

OutputVoltage(V)

Frequency(MHz)

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

Input =100dB

fmod.=1kHz

Vcc =3.0V

AF Output Voltage & T.H.D. vs. Input Level

0

10

20

30

12.0

10.0

8.0

6.0

4.0

2.0

0.0

20 40 60 80 100 120

AF

outputvoltage(dB)

T.

H.

D.

(%)

Input level (dB)

fdev.=80kHz

fmod.=1kHz

Vcc =3.0V

AF ouotput voltage

T.H.D.[%]


24/2722


P11E.pdf 02.10.30

10 Appendix

1. Correct Use of Ceramic Discriminator

Accura te Circuit va lues ar e required to obtain specified

electrica l cha ra cteristic. In case of input /output

impedance mismatching or application to unsuitable IC,

it ma y cause char acterist ic shift. We would like to

recommend to inquire a ppropriat e cera mic

discriminat or an d circuit condition to your a pplication

to us fixing circuit design.

2. Applied IC Reference Table for Ceramic Discriminator

Example : CDSCA10M7GA027- R0

q Pr oduct ID

CDS CA : SMD Type

CD ALA : Lea d Type

w Nominal Center Frequency

10M7 : 10.7 MH z

e Type and Fr equency Ran k Code

r Applied IC C ode

ex.) 027 : CXA1238 (SONY)

100 : TA2149N (TOS H IB A)

*Plea se see following ta ble for r eference applied IC. I f

you can n ot find IC par t number seeking, please

contact our sales representative.

t Packaging

q w e r t

Code Packaging

B0

A0

R0

Bulk

Radial Taping H0=18 mm

Plastic Taping =180 mm

IC Manufacturer IC Part Number rSuffix Number

ATMEL

INFINEON

MATSUSHITA

MOTOROLA

NEC

PHILIPS

U2501B

U2765B

U4313B

U4490B

U829B

TDA1576T

TDA6160X

TDA6160-2X

AN6138SH

AN7004

AN7006S

AN7007SU

AN7232

MC13156

MC13158

MC13173

MC3363

PC1391M

NE604

SA605

SA626SA636DK

SA639

TBA120U

TBA229-2

TDA1596T

TDA2557

TEA5591

TEA5592

TEA5594

TEA5710

TEA5712T

TEA5757HL

TEA5762 / 5757

UAA3220TS

028

095

081

034V

025

051

038

044

097

011

014A

013

053

049

073

052

087

056

020

042

047096

085

029

021A

120

024

017

030

035

040

055

105A

061

098

0


25/2723


P11E.pdf 02.10.30

10

10Appendix


RFMD

ROHM

SAMSUNG

SANYO

SONY

RF2905

RF2925

BA1440

BA1448

BA4110

BA4220

BA4230AF

BA4234L

BA4240L

KA22425

KA2244

KA22901

KA2292

KA2295

KA2297

KA2298B

KB22902

S1A0903

LA1150

LA1225M

LA1260

LA1805

LA1810

LA1814M

LA1816

LA1822

LA1823

LA1827M

LA1830

LA1831

LA1832/M

LA1833

LA1835/MLA1838/M

LA7770

LV23000M

LV23100V

CX1691M

CX-20029

CX-20076

CXA1030P

CXA1111

CXA1238

CXA1238N

CXA1343M

CXA1376AM

CXA1538M/N/S

111

104

019

060

066

041

005

004

067

089

059

090

063

064

091

065

103

118A

070

108A

007

026

022

115

015

094

101

083

037

043

046

086

048079

023

114

121

078

001

002

012

093

027

027N

032

054

069


SONY

T.I.

TOKO

TOSHIBA

CXA1611

CXA1619B

CXA1991N

CXA3067M

TRF6901

TK14570L

TK14581

TK14583V

TK14588V

TA2003

TA2007N

TA2008A/AN

TA2022

TA2029

TA2046

TA2057

TA2099N

TA2104AFN

TA2104F

TA2111N/F/FN

TA2132

TA2132BP

TA2142FN

TA2149AN

TA2149N

TA2154FN

TA2159F

TA31161

TA31272F

TA7130P

TA7303P

TA7640AP

TA7765AFTA8122AN/AF

TA8132AN/AF

TA8186

TA8721ASN

075

117

068

076

119

122

062

112

109

031

033

045

050

036

058

057

082

080

080A

077

092

092D

102

100A

100

113

116

072

107

009

008

006

071016

018

039

088


26/2724


P11E.pdf 02.10.30

10 Appendix

Area / CountryFrequency [MHz]

AP S C P AS P-S System

52.75

39.75

39.75

31.50

30.00

31.50

39.75

31.50

39.75

39.75

39.75

39.75

31.90

31.50

40.70

30.00

29.875

31.90

29.875

31.90

54.25

41.25

41.25

33.50

31.50

33.50

41.25

33.50

41.25

41.25

41.25

41.25

33.40

33.50

39.20

31.50

31.375

33.40

33.40

33.40

55.17

42.17

42.17

35.07

33.57

35.07

42.17

35.07

42.17

42.17

42.17

42.17

34.47

35.07

37.10

35.57

37.445

34.47

34.47

34.47

58.75

45.75

45.75

39.50

38.00

39.50

45.75

39.50

45.75

45.75

45.75

45.75

38.90

39.50

32.70

38.00

36.875

38.90

38.90

38.90

60.25

47.25

47.25

41.50

39.50

41.50

47.25

41.50

47.25

47.25

47.25

47.25

40.40

41.50

31.20

39.50

38.375

40.40

40.40

40.40

4.5

4.5

4.5

6.0

6.5

6.0

4.5

6.0

4.5

4.5

4.5

4.5

5.5

6.0

6.5

6.5

5.5

5.5

5.5

5.5

NTSC

NTSC

NTSC

PAL

PAL

PAL

NTSC

PAL

NTSC

NTSC

NTSC

PAL

PAL

PAL

SECAM

SECAM

PAL

PAL

PAL

SECAM

Asia

ASEAN

Japan

Korea

Taiwan

Hong Kong

China

India

Philippine

Malaysia

Canada

U.S.A.

Mexico

Brazil

Germany

U.K.

France

Russia

Australia

New Zealand

Nigeria

Saudi Arabia

!Intermediate Frequency of Television System in the World

North

and

SouthAmerica

Europe

OtherArea

Remarks

P : P ict ur e S ign a l

C : C hr om a t ic S ig na l

S : S oun d S ign al

AP : Adjacent Cha nnel P icture Signal

AS : Adjacent Cha nnel Sound Signal

0


27/27

Note:1. Export Control

Murata products should not be used or sold for use in the development, production, stockpiling or utilization of any conventional weapons or mass-destructive

weapons (nuclear weapons, chemical or biological weapons, or missiles), or any other weapons.

For products which are controlled items subject to the Foreign Exchange and Foreign Trade Law of Japan, the export license specified by the law is requiredfor export.

2. Please contact our sales representatives or product engineers before using our products listed in this catalog for the applications listed below which requireespecially high reliability for the prevention of defects which might directly cause damage to the third party's life, body or property, or when intending to use one

of our products for other applications than specified in this catalog.

q Aircraft equipment w Aerospace equipmente Undersea equipment r Power plant equipmentt Medical equipment y Transportation equipment (vehicles, trains, ships, etc.)

u Traffic signal equipment i Disaster prevention / crime prevention equipmento Data-processing equipment !0 Application of similar complexity and/or reliability requirements to the applications listed in the above

3. Product specifications in this catalog are as of July 2002. They are subject to change or our products in it may be discontinued without advance notice. Pleasecheck with our sales representatives or product engineers before ordering. If there are any questions, please contact our sales representatives or product

engineers.

4. Please read rating and CAUTION (for storage and operating, rating, soldering and mounting, handling) in this catalog to prevent smoking and/or burning, etc.

5. This catalog has only typical specifications because there is no space for detailed specifications. Therefore, please approve our product specification or transactthe approval sheet for product specification before ordering.

6. Please read CAUTION and Notice in this catalog for safety. This catalog has only typical specifications. Therefore you are requested to approve our productspecification or to transact the approval sheet for product specification, before ordering.

7. Please note that unless otherwise specified, we shall assume no responsibility whatsoever for any conflict or dispute that may occur in connection with the effect

of our and/or third party's intellectual property rights and other related rights in consideration of your using our products and/or information described orcontained in our catalogs. In this connection, no representation shall be made to the effect that any third parties are authorized to use the rights mentioned

above under licenses without our consent.

8. No ozone depleting substances (ODS) under the Montreal Protocol are used in our manufacturing process.

http://www.murata.com/


P11E.pdf 02.10.30

cerafil app manual

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