SIST EN 60368-2-2:2002

SLOVENSKI STANDARD
SIST EN 60368-2-2:2002
01-september-2002
Piezoelectric filters - Part 2: Guide to the use of piezoelectric filters - Section 2:
Piezoelectric ceramic filters (IEC 60368-2-2:1996)
Piezoelectric filters -- Part 2: Guide to the use of piezoelectric filters -- Section 2:
Piezoelectric ceramic filters
Piezoelektrische Filter -- Teil 2: Leitfaden für die Anwendung von piezoelektrischen
Filtern -- Hauptabschnitt 2: Piezoelektrische Keramikfilter
Filtres piézoélectriques -- Partie 2: Guide d'emploi des filtres piézoélectriques -- Section
2: Filtres à céramique piézoélectrique
Ta slovenski standard je istoveten z: EN 60368-2-2:1999
ICS:
31.140 3LH]RHOHNWULþQHLQ Piezoelectric and dielectric
GLHOHNWULþQHQDSUDYH devices
31.160 (OHNWULþQLILOWUL Electric filters
SIST EN 60368-2-2:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60368-2-2:2002

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SIST EN 60368-2-2:2002

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SIST EN 60368-2-2:2002

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SIST EN 60368-2-2:2002

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SIST EN 60368-2-2:2002

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SIST EN 60368-2-2:2002
NORME CEI
INTERNATIONALE IEC
60368-2-2
INTERNATIONAL
Première édition
STAN DARD
First edition
1996-07
Filtres piézoélectriques
Deuxième partie:
Guide d'emploi des filtres piézoélectriques
Section 2 — Filtres à céramique piézoélectrique
Piezoelectric filters
Part 2:
Guide to the use of piezoelectric filters
Section 2 — Piezoelectric ceramic filters
© IEC 1996 Droits de reproduction réservés — Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun any form or by any means, electronic or mechanical,
procédé, électronique ou mécanique, y compris la photo- including photocopying and microfilm, without permission in
copie et les microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: inmail@iec.ch IEC web site http: //www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
PRICE CODE
International Electrotechnical Commission
IEC
MenigyHapo Hae 3neKTpoTeXHN4eCHaR HOMNCCNH
Pour prix, voir catalogue en vigueur
•
For price, see current catalogue

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SIST EN 60368-2-2:2002
_ 3 —
368-2-2 © IEC:1996
CONTENTS
Page
FOREWORD 5
INTRODUCTION 7
Clause
1 Scope 11
2 Normative references 11
3 Terms and definitions 11
3.1 General terms 11
3.2 Electrical properties 13
4 Piezoelectric ceramic resonators for filters 15
4.1 General 15
4.2 Mode of vibration as a function of frequency 17
5 Basic filter characteristics 19
5.1 Types of piezoelectric ceramic filters 19
5.2 Utilization and limitations 33
5.3 Input level 37
6 Practical remarks 39
6.1 Impedance matching 39
6.2 Spurious response suppression 41
7 Measuring techniques 41
8 Marking 41
9 Specification procedure for a piezoelectric ceramic filter 43

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SIST EN 60368-2-2:2002
368-2-2 © IEC:1996 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
PIEZOELECTRIC FILTERS —
Part 2: Guide to the use of piezoelectric filters —
Section 2: Piezoelectric ceramic filters
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization
comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to
promote international cooperation on all questions concerning standardization in the electrical and
electronic fields. To this end and in addition to other activities, the IEC publishes International Standards.
Their preparation is entrusted to technical committees; any IEC National Committee interested in
the subject dealt with may participate in this preparatory work. International, governmental and
non-governmental organizations liaising with the IEC also participate in this preparation. The IEC
collaborates closely with the International Organization for Standardization (ISO) in accordance with
conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of the IEC on technical matters, express as nearly as possible an
international consensus of opinion on the relevant subjects since each technical committee has
representation from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the
form of standards, technical reports or guides and they are accepted by the National Committees in that
sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the
subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 368-2-2 has been prepared by IEC technical committee 49:
Piezoelectric and dielectric devices for frequency control and selection.
IEC 368-2-2 cancels and replaces IEC 368B, published in 1975, and constitutes a
technical revision.
IEC 368: Piezoelectric filters, comprises:
- IEC 368-1: Part 1: General information, standard values and test conditions (1992).
- IEC 368-2: Part 2: Guide to the use of piezoelectric filters, which comprises:
- IEC 368-2-1: Section 1: Quartz crystal filters (1988).
IEC 368-2-2: Section 2: Piezoelectric ceramic filters (1996).
IEC 368-3: Part 3: Standard outlines (1991).
The text of this standard is based on the following documents:
FDIS Report on voting
49/317/FDIS 49/348/RVD
Full information on the voting for the approval of this standard can be found in the report
on voting indicated in the above table.

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SIST EN 60368-2-2:2002
368-2-2 © I EC:1996 – 7 –
INTRODUCTION
In accordance with the progress in research and development of stable piezoelectric
ceramic materials a new, rather promising field has appeared in designing high quality,
miniature and economical filters using piezoelectric ceramic resonators (hereinafter
referred to as ceramic resonators).
The availability of ceramic resonators with a high coupling factor, a high quality factor, and
a satisfactory stability has permitted a design of a piezoelectric ceramic filter which can be
used as an alternative to conventional LC filters, mechanical filters, as well as for new
applications.
Piezoelectric ceramic filters (hereafter referred to as ceramic filters) are at present widely
used in communication (in IF amplifiers of communication receivers), in equipment for
forming a set of reference frequencies, and also in telemetry and measurement applica-
tion, as well as in the IF amplifiers of broadcast receivers. Although specifications for
these filters are very diverse, many of the above needs can be served by a few standard
types of ceramic filters.
The standard detail specifications (in the IEC 368 and IEC 1261 series) and national speci-
fications or data sheets issued by manufacturers will define the available combinations of
reference frequency, pass bandwidth, ripple, shape factor, terminating impedance, etc.
These sheets are compiled to include a wide range of ceramic filters with standardized
performances. It cannot be overemphasized that the user should, wherever possible,
select his ceramic filters from these specification sheets, when available, even if it may
lead to making small modifications to his circuit to enable standard filters to be used. This
is especially so in the case of the selection of the reference frequency.
In contrast to conventional LC filters, ceramic filters, as well as quartz crystal filters, offer
substantial advantages in design and production costs, when their reference frequencies
are limited to a few narrow frequency ranges. Hence, an order which does not specify one
of the more commonly used reference frequencies may be uneconomical.
It should be understood that standardization is not a fixed process, but rather a continuing
one. As new requirements arise, new detail specifications are prepared to meet these
requirements.
It is of prime interest to a user that the filter characteristics should satisfy the requirements
of a specification sheet. The selection of internal filter and resonator networks to meet that
specification should be an option of the manufacturer.
The amplitude versus frequency characteristics of a filter are usually expressed in terms of
transducer attenuation as a function of frequency, as shown in figure 1. In some
applications, such characteristics as transient response or group delay time are more
important than transducer attenuation.

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SIST EN 60368-2-2:2002
368-2-2 © IEC:1996 — 9 —
Transducer attenuation characteristics are further specified by reference frequency,
minimum transducer attenuation, pass-band ripple and shape factor, of which standard
values are given in IEC 368-1 and IEC 1261-1. The specification is to be satisfied between
the lowest and highest temperature of the specified operating temperature range. This
condition should also be satisfied before and after the environmental tests. In some cases,
particularly for filters for broadcast receivers, the maximum variation of characterisics over
a given temperature range may be specified.

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SIST EN 60368-2-2:2002
368-2-2 © IEC:1996 - 11 -
PIEZOELECTRIC FILTERS —
Part 2: Guide to the use of piezoelectric filters —
Section 2: Piezoelectric ceramic filters
1 Scope
This section of IEC 368-2 describes passive band-pass filters operating over the
frequency range of a few kHz to more than 10 MHz which are commercially available as
separate and independent units. It is not the aim of this standard to explain theory, nor to
attempt to cover all the eventualities which may arise in practical circumstances.
This standard draws attention to some of the fundamental questions which should be
considered by the user before he places an order for a filter for a new application. Such a
procedure will be the user's insurance against unsatisfactory performance.
2 Normative references
The following normative documents contain provisions which, through reference in this
text, constitute provisions of this section of IEC 368-2. At the time of publication, the
editions indicated were valid. All normative documents are subject to revision, and pa rties
to agreements based on this section of IEC 368-2 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated
below. Members of IEC and ISO maintain registers of currently valid International
Standards.
IEC 368-1: 1992, Piezoelectric filters - Part 1: General information, standard values and
test conditions
IEC 1261-1: 1994, Piezoelectric ceramic filters for use in electronic equipment - A speci-
fication in the IEC quality assessment system for electronic components (IECQ) - Pa rt 1:
Generic specification - Qualification approval
IEC 1261-2: 1994,
Piezoelectric ceramic filters for use in electronic equipment - A speci-
fication in the IEC quality assessment system for electronic components (IECQ) - Pa rt 2:
Sectional specification - Qualification approval
IEC 1261-2-1: 1994, Piezoelectric ceramic filters for use in electronic equipment - A speci-
fication in the IEC quality assessment system for electronic components (IECQ) - Part 2:
Sectional specification - Qualification approval - Section 1: Blank detail specification -
Assessment level E
3 Terms and definitions
For the purpose of this section of IEC 368-2, the following terms and definitions apply.
3.1 General terms
3.1.1 piezoelectric ceramic resonator: Piezoelectric ceramic element with electrodes
which can be made to vibrate in a particular mode of vibration.

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SIST EN 60368-2-2:2002
368-2-2 © IEC:1996 - 13 -
3.1.2 polarization: Orientation of the polarization axis in one direction by applying a high
d.c. electric field at high temperature in order to create the piezoelectric effect in a
ceramic material.
3.1.3 electrode: Electrically conductive plate or film in contact with, or in proximity to, a
face of a ceramic element, by means of which an electric field can be applied to the
element.
3.1.4 mode of vibration: Pattern of motion of the individual particles in a vibrating body
resulting from stresses applied to the body.
The most common modes of vibration are:
a) area expansion mode;
b) trapped thickness shear mode;
c) trapped thickness expansion mode.
NOTE - Applicable frequency range is referred to in figure 2.
3.2 Electrical properties
3.2.1 Geometrical mean of the cut-off frequencies. However, the
mid-band frequency:
mid-band frequency might be defined as the minimum transducer attenuation for some
specific applications.
NOTE - In practice, the arithmetic mean is often used as a good approximation to the geometric mean.
3.2.2 pass-band: Band of frequencies in which the relative attenuation is equal to or less
than a specified value.
3.2.3 Logarithmic ratio of the power delivered to the load
insertion attenuation:
impedance before insertion of the filter to the power delivered to the load impedance after
insertion of the filter.
3.2.4
pass-band ripple: Difference between the maximum and minimum attenuation in
the pass band or in a specified portion of the pass-band.
3.2.5 selectivity: Difference between the attenuation at the given frequency outside the
pass-band and the reference value at a given reference frequency. The reference
frequency might be specified according to its application.
3.2.6 State of resonance of a piezoelectric ceramic resonator other
unwanted response:
than that associated with the characteristic frequency (such as mid-band frequency).
3.2.7 operating temperature range: Range of temperatures over which the piezoelectric
ceramic filter works within the specified tolerances.
3.2.8 reference temperature: Temperature at which piezoelectric ceramic filter measure-
ments are made. The reference temperature is the mid-point of the controlled temperature
range.

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SIST EN 60368-2-2:2002
368-2-2 © IEC:1996 - 15 -
The reference temperature is normally (25 ± 2) °C.
3.2.9 ageing: (long-term parameter variation): Relation which exists between the
reference frequency and time.
NOTE - It will be specified, according to user's request, when piezoelectric ceramic filters are used under
severe requirements for frequency accuracy.
Minimum transducer
attenuation
Figure 1 - Transducer attenuation characteristic of a filter
4 Piezoelectric ceramic resonators for filters
4.1 General
Materials, the whole body of which are of crystal, are called single crystals, while those
comprised of many crystal bodies are called ceramics.

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SIST EN 60368-2-2:2002
368-2-2 © IEC:1996 — 17 —
Piezoelectric ceramics are composed of many crystals. Single crystals, like a quartz
crystal, in which the internal polarization axes are all oriented in one direction, can be
used as piezoelectric materials as they are.
Ceramics, however, which are composed of fine crystals, unevenly directed, do not show
the piezoelectric effect, since the crystals' polar axes are oriented in random directions. In
this case, ceramics act as dielectric materials. In order to create the piezoelectric effect in
ceramics, it is necessary to orient the polarization axis in one direction.
This is accomplished by applying a direct electric field of high intensity for a long time, and
the process is referred to as the polarization treatment.
The basic materials for piezoelectric ceramic resonators are lead titanate-zirconate and
lead titanate. The temperature coefficient of the resonance frequency can be adjusted by
changing the lead zirconate to lead titanate ratio for each mode of vibration.
Physical dimensions are tightly controlled, since they determine the resonance frequency.
The resonance frequencies are inversely proportional to physical dimensions. The one
exception is thickness in the flexural mode of vibration.
Typical data for piezoelectric ceramics used for filters are listed in table 1. In this table,
the frequency constants are the resonance frequency for the planar expansion mode
multiplied by the diameter of a ceramic disc. Coupling coefficients also apply for the planar
expansion mode.
Table 1 – Typical data on piezoelectric ceramics used for filters
Frequency Coupling
Material Permittivity Om
constant coefficient k
m/s % £
PZT-60 2510
35 790 830
PZT-6E 2040 31 820 1130
PCM-18 1200
2520 39 1800
PCM-67 2580 32 620 3130
4.2 Mode of vibration as a function of frequency
The frequency range covered commercially by piezoelectric ceramic resonators is
generally from 10 kHz to 30 MHz. Mechanical resonance is classified according to the
vibration direction and the type of waves generated.
This is referred to as the mode of vibration, which depends on the shape of electrodes,
direction of polarization, and driving direction. Various modes result in various frequency
ranges of the resonator.

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SIST EN 60368-2-2:2002
368-2-2 © IEC:1996 -
19 -
Figure 2 shows typical modes of vibration and frequency ranges.
Frequency Hz
1k 10 k 100k 1 M 10 M 100 M 1G
Mode of vibration
Flexural }^
vibration
1
Length
vibration 0
Expansion R !.
vibration •
-"";
Radial R .
r y
vibration
Trapped shear
thickness shear
f a
Trapped vibration
thickness
/ I I
Note - The
...