IEC 60122-4:2019

IEC 60122-4 ®
Edition 1.0 2019-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Quartz crystal units of assessed quality –
Part 4: Crystal units with thermistors

Résonateurs à quartz sous assurance de la qualité –
Partie 4: Résonateurs à quartz équipés de thermistances

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IEC 60122-4 ®
Edition 1.0 2019-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Quartz crystal units of assessed quality –

Part 4: Crystal units with thermistors

Résonateurs à quartz sous assurance de la qualité –

Partie 4: Résonateurs à quartz équipés de thermistances

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.140 ISBN 978-2-8322-6457-7

– 2 – IEC 60122-4:2019 © IEC 2019
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms, definitions, units and symbols . 6
3.1 Terms and definitions . 6
3.2 Units and symbols. 6
4 Specifications . 6
4.1 General . 6
4.2 Structure of crystal units with thermistors . 7
4.3 Handling of the thermistor . 7
4.4 Shipping requirements . 7
5 Delivery conditions . 8
6 Quality and reliability . 8
Annex A (informative) Effect of frequency stability using crystal units with thermistors . 9
A.1 Object . 9
A.2 Comparison of conventional crystal units with crystal units with thermistors . 9
A.3 Verification test of crystal units with thermistors . 10
A.3.1 Test condition . 10
A.3.2 Test result . 11
A.4 Example of crystal units with thermistors . 12
A.4.1 Structure . 12
A.4.2 Terminal functions . 13
Bibliography . 14

Figure 1 – Block diagrams of the quartz crystal units . 7
Figure A.1 – Conventional crystal oscillator with thermistor . 9
Figure A.2 – Conceptual diagram for crystal units with thermistors . 10
Figure A.3 – Test condition . 11
Figure A.4 – Test result . 12
Figure A.5 – Crystal units with thermistors inside enclosure (side view) . 13
Figure A.6 – Crystal units with thermistors outside enclosure (side view) . 13
Figure A.7 – Typical example of crystal units with thermistors – Terminal functions . 13

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
QUARTZ CRYSTAL UNITS OF ASSESSED QUALITY –

Part 4: Crystal units with thermistors

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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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 IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
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expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60122-4 has been prepared by IEC technical committee TC 49:
Piezoelectric, dielectric and electrostatic devices and associated materials for frequency
control, selection and detection.
The text of this International Standard is based on the following documents:
CDV Report on voting
49/1281/CDV 49/1291/RVC
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60122 series, published under the general title Quartz crystal units
of assessed quality, can be found on the IEC website.

– 4 – IEC 60122-4:2019 © IEC 2019
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
QUARTZ CRYSTAL UNITS OF ASSESSED QUALITY –

Part 4: Crystal units with thermistors

1 Scope
This part of IEC 60122 is applicable to crystal units with thermistors mainly used in the field of
mobile communication that requires high frequency stability such as local reference signal
generator for the mobile phone base station or GPS. This document provides users with
technical guidelines of crystal units with thermistors as well as basic knowledge of common
crystal units with thermistors.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60027 (all parts), Letter symbols to be used in electrical technology
IEC 60050-561, International Electrotechnical Vocabulary – Part 561: Piezoelectric, dielectric
and electrostatic devices and associated materials for frequency control, selection and
detection
IEC 60068 (all parts), Environmental testing
IEC 60122-1:2002, Quartz crystal units of assessed quality – Part 1: Generic specification
IEC 60122-1:2002/AMD1:2017
IEC 60122-2-1, Quartz crystal units for frequency control and selection – Part 2: Guide to the
use of quartz crystal units for frequency control and selection – Section One: Quartz crystal
units for microprocessor clock supply
IEC 60444-1, Measurement of quartz crystal unit parameters by zero phase technique in a pi-
network – Part 1: Basic method for the measurement of resonance frequency and resonance
resistance of quartz crystal units by zero phase technique in a pi-network
IEC 60444-5, Measurement of quartz crystal unit parameters – Part 5: Methods for the
determination of equivalent electrical parameters using automatic network analyzer
techniques and error correction
IEC 60444-9, Measurement of quartz crystal unit parameters – Part 9: Measurement of
spurious resonances of piezoelectric crystal units
IEC 60539-1:2016, Directly heated negative temperature coefficient thermistors – Part 1:
Generic specification
IEC 60617 (all parts), Graphical symbols for diagrams (available at http://std.iec.ch/iec60617)
IEC 63041-1, Piezoelectric sensors – Part 1: Generic specifications

– 6 – IEC 60122-4:2019 © IEC 2019
ISO 80000-1:2009, Quantities and units – Part 1: General
3 Terms, definitions, units and symbols
For the purposes of this document, the terms and definitions given in IEC 60027 (all parts),
IEC 60050-561, IEC 60617, IEC 63041-1 and ISO 80000-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 Terms and definitions
3.1.1
FT curve coefficient
coefficient of first, second and third order frequency temperature characteristic curve
3.1.2
residual frequency stability slope
temperature differential of difference between actual FT data and calculated FT value
3.1.3
normal zero-power resistance
normal value at the standard reference temperature of 25 °C, unless otherwise specified
[SOURCE: IEC 60539-1: 2016, 3.19]
3.1.4
B-value
index of the thermal sensitivity
[SOURCE: IEC 60539-1: 2016, 3.22]
3.2 Units and symbols
Crystal units with thermistors covered in this document are those used for the high stability
signal generator. For the purposes of this document, units and letter symbols shall, wherever
possible, be taken from the following standards: IEC 60027, IEC 60050-561, IEC 60617,
IEC 63041-1 and ISO 80000-1:2009.
4 Specifications
4.1 General
Crystal units with thermistors are used for the high stability signal generator. For example, a
local reference signal generator is synchronized to the mobile phone base station, or a local
reference signal generator for receiving a signal from satellite positioning system represented
by Navigation Satellite System.
Characteristics related to crystal units shall follow IEC 60122-2-1, IEC 60444-1, IEC 60444-5,
and IEC 60444-9.
Environmental testing shall meet the requirements of IEC 60068 (all parts).

Concepts and specifications for the crystal units with thermistors are shown in detail in 4.2
to 4.4.
4.2 Structure of crystal units with thermistors
Quartz crystal and thermistor are placed inside or outside enclosures that are different from
conventional crystal units.
And equipped with external terminal for quartz crystal and for thermistor (see Figure 1).

a) Conventional quartz crystal resonator units

b) Quartz crystal units with thermistors
Figure 1 – Block diagrams of the quartz crystal units
The effect of frequency stability using crystal units with the thermistors and actual structures
are described in Annex A.
4.3 Handling of the thermistor
Thermistor position and fixing method shall be considered as follows:
– Damage for thermistor during handling.
– Fixation method considering solder heating experienced when the product is used.
4.4 Shipping requirements
The requirements listed below shall be specified upon agreement between the supplier and
the user:
– First, second and third order FT curve coefficient.
– Residual frequency stability slope.
– Normal zero-power resistance.
– B-value.
– 8 – IEC 60122-4:2019 © IEC 2019
5 Delivery conditions
Clause 3 of IEC 60122-1:2002 applies.
6 Quality and reliability
Clauses 4 of IEC 60122-1:2002 and IEC 60122-1/AMD1:2017 apply.

Annex A
(informative)
Effect of frequency stability using crystal units with thermistors
A.1 Object
The object of Annex A is to describe crystal units with thermistors in detail and the effect of
frequency stability, and examples.
A.2 Comparison of conventional crystal units with crystal units with
thermistors
Figure A.1 shows the conventional TCXO (temperature compensated crystal oscillator) with
crystal units and thermistor. In the figure, crystal unit and thermistor on the PCB are
described.
The thermistor gives a voltage according to ambient temperature that is converted from
analogue to digital data. The digital data will pick up the voltage data from the pre-set memory.
The voltage data will convert to analogue voltage and control VCXO to compensate frequency.
Accuracy of compensation will be better if the thermistor provides voltage that corresponds as
much as possible to the actual crystal temperature.
However, in this structure, temperature difference between the crystal blank and thermistor is
large due to the different positions of each part. The temperatures of crystal blank and
thermistor are mainly dependent on the position of other parts on the PCB that generate heat.
Due to this temperature difference, compensated frequency stability is not small.

Figure A.1 – Conventional crystal oscillator with thermistor
Figure A.2 shows crystal units with thermistors on PCB.
The frequency compensation system is the same as that shown in Figure 1, but it is
distinguished to use crystal units with thermistors.
In this structure, thermistors are placed near the crystal because the temperature difference
between crystal blank and thermistor is small. This small difference in temperature between
the crystal blank and thermistor leads to small compensated frequency stability.

– 10 – IEC 60122-4:2019 © IEC 2019

Figure A.2 – Conceptual diagram for crystal units with thermistors
A.3 Verification test of crystal units with thermistors
A.3.1 Test condition
Crystal units with thermistors and a thermistor are mounted on a test PCB. Put the test PCB
in oven and measure frequency, thermistor resistance inside crystal, and thermistor
resistance on PCB by changing temperature from -30 °C to 90 °C. (Figure A.3).
Temperature ramp-up conditions are given below:
– Test 1: Thermistor resistance is taken from crystal units with thermistors; ramp-up speed
is 0,2 °C/min. This ramp-up speed is slow and that will not give temperature difference
between crystal and thermistor.
– Test 2: Thermistor resistance is taken from a thermistor mounted on a test PCB; ramp-up
speed is 5 °C /min, that is 25 times faster than test 1.
– Test 3: Thermistor resistance is taken from crystal units with thermistors; ramp-up speed
is 5 °C /min, that is 25 times faster than test 1.

Figure A.3 – Test condition
A.3.2 Test result
Test 1 is considered as the real crystal temperature characteristic. Test 2 and Test 3 are
faster ramp-up speeds, Test 3 is nearer than Test 2 in temperature characteristic. (Figure A.4).

– 12 – IEC 60122-4:2019 © IEC 2019

Figure A.4 – Test result
A.4 Example of crystal units with thermistors
A.4.1 Structure
There are two typical positions of thermistors: mounted inside enclosure (Figure A.5) or
outside enclosure (Figure A.6) with consideration of mount quality.
a) Crystal units with thermistors inside enclosure
A thermistor inside enclosure (Figure A.5) is featured as described below:
– There is no risk of short circuit between thermistor and crystal’s pads, also no damage
to thermistor.
– Back side terminal can be large (shock assuagement by solder).

– There is no risk under resin molding (heat release by resin). Thermistor terminal is
close to crystal’s pads.
– There is no risk of re-melting at junction at thermistor and package when mounted on
PCB.
b) Crystal units with thermistors outside enclosure
A thermistor outside enclosure (Figure A.6) is featured as described below:
– Cost-efficient due to the fact that thermistors are mounted after crystal inspection.
– Smaller temperature difference between crystal and thermistor.
– Less limitation given by connection of thermistor.

Figure A.5 – Crystal units with thermistors inside enclosure (side view)

Figure A.6 – Crystal units with thermistors outside enclosure (side view)
A.4.2 Terminal functions
T
...