prEN IEC 60444-11:2025

Measurement of quartz crystal unit parameters - Part 11: Standard method for the determination of the load resonance frequency fl and the effective load capacitance cleff using automatic network analyzer techniques and error correction

Messung von Schwingquarz-Parametern - Teil 11: Standardverfahren zur Bestimmung der Lastresonanzfrequenz fL und der effektiven Lastkapazität CLeff mit automatischer Netzwerkanalysatortechnik und Fehlerkorrektur

Mesure des paramètres unitaires quartz - Partie 11: Méthode standard pour la détermination de la fréquence de résonance de charge fl et de la capacité de charge effective cleff à l'aide de techniques d'analyseur de réseau automatiques et de correction d'erreur

Meritev parametrov kvarčnokristanih enot - 11. del: Standardne metode za ugotavljanje obremenitvene resonančne frekvence fL in efektivne obremenitvene kapacitivnosti CLeff z uporabo tehnik z avtomatičnim omrežnim analizatorjem in popravljanjem napak

General Information

• Status: Not Published
• Publication Date: 12-Oct-2026
• ICS: 31.140 - Piezoelectric devices
• Technical Committee: CLC/SR 49 - Piezoelectric and dielectric devices for frequency control and selection
• Current Stage: 4060 - Enquiry results established and sent to TC, SR, BTTF - Enquiry
• Start Date: 13-Jun-2025
• Completion Date: 13-Jun-2025
• Ref Project: oSIST prEN IEC 60444-11:2025 - Measurement of quartz crystal unit parameters - Part 11: Standard method for the determination of the load resonance frequency fL and the effective load capacitance CLeff using automatic network analyzer techniques and error correction

Relations

• Revises: EN 60444-11:2010 - Measurement of quartz crystal unit parameters - Part 11: Standard method for the determination of the load resonance frequency fL and the effective load capacitance CLeff using automatic network analyzer techniques and error correction
• Effective Date: 26-Sep-2023

Overview

prEN IEC 60444-11:2025 defines a standard measurement method for determining the load resonance frequency (fL) and the effective load capacitance (CLeff) of quartz crystal units using automatic network analyzer techniques with error correction. This second edition (replacing the 2010 edition) formalizes an error-corrected, automated method that improves accuracy and reproducibility compared with the older manual technique, extends the practical measurement range to about 200 MHz, and allows determination of equivalent crystal parameters in a single test sequence.

Key topics and technical requirements

• Measurement principle: Finds the frequency where the crystal reactance equals the negative reactance of the equivalent load capacitance (X = –XCL), enabling accurate identification of fL and CLeff.
• Automatic network analyzer techniques: Uses automated S-parameter/admittance measurements rather than physical load capacitors, improving throughput and correlation to application conditions.
• Error correction and calibration: Incorporates error-correction procedures (based on IEC 60444-5 techniques) and calibration resistances/fixtures to minimise systematic measurement errors.
• Accuracy and reproducibility: Specifies evaluation of measurement accuracy, reproducibility and limitations, including analysis of noise, voltage measurement errors and calibration contributions.
• Single-sequence parameter extraction: Allows extraction of load resonance frequency, effective load capacitance and equivalent crystal parameters without changing the test fixture.
• Annex A (informative): Retains the main content of the withdrawn manual method (IEC TR 60444-4) for user convenience; the automated method is the normative reference in case of dispute.
• Scope limits: Notes practical upper-frequency applicability (~200 MHz) and references figure of merit definitions from IEC 60122-1:2002.

Applications and users

Who benefits from this standard:

• Crystal and oscillator manufacturers - production test, acceptance criteria and characterization of quartz units.
• Component test laboratories and calibration houses - reproducible measurement procedures and traceable error correction.
• R&D and design engineers - accurate parameter extraction for oscillator design, pulling sensitivity and frequency control.
• Quality assurance and compliance teams - standardized method for product specifications and comparison across suppliers.

Practical uses:

• Characterizing load resonance behavior for oscillator circuit design.
• Measuring effective load capacitance for specified nominal frequencies.
• Replacing manual load-capacitor methods to increase throughput and extend frequency capability.

Related standards

• IEC 60444-5 (error-corrected measurement techniques) - referenced foundation for error correction.
• IEC 60122-1:2002 - figure of merit and related parameter definitions.
• IEC TR 60444-4 - manual measuring method (withdrawn) whose contents are included in Annex A for reference.

Keywords: IEC 60444-11, quartz crystal unit, load resonance frequency fL, effective load capacitance CLeff, automatic network analyzer, error correction, crystal measurement, frequency control, piezoelectric devices.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2025
Meritev parametrov kvarčnokristanih enot - 11. del: Standardne metode za
ugotavljanje obremenitvene resonančne frekvence fL in efektivne obremenitvene
kapacitivnosti CLeff z uporabo tehnik z avtomatičnim omrežnim analizatorjem in
popravljanjem napak
Measurement of quartz crystal unit parameters - Part 11: Standard method for the
determination of the load resonance frequency fL and the effective load capacitance
CLeff using automatic network analyzer techniques and error correction
Mesure des paramètres unitaires quartz - Partie 11: Méthode standard pour la
détermination de la fréquence de résonance de charge fl et de la capacité de charge
effective cleff à l'aide de techniques d'analyseur de réseau automatiques et de correction
d'erreur
Ta slovenski standard je istoveten z: prEN IEC 60444-11:2025
ICS:
31.140 Piezoelektrične naprave Piezoelectric devices
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

49/1489/CDV
COMMITTEE DRAFT FOR VOTE (CDV)

PROJECT NUMBER:
IEC 60444-11 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2025-03-21 2025-06-13
SUPERSEDES DOCUMENTS:
49/1467/CD, 49/1478/CC
IEC TC 49 : PIEZOELECTRIC, DIELECTRIC AND ELECTROSTATIC DEVICES AND ASSOCIATED MATERIALS FOR FREQUENCY
CONTROL, SELECTION AND DETECTION
SECRETARIAT: SECRETARY:
Japan Mr Masanobu Okazaki
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):

ASPECTS CONCERNED:
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some
Countries” clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is
the final stage for submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
Measurement of quartz crystal unit parameters - Part 11: Standard method for the
determination of the load resonance frequency fL and the effective load capacitance CLeff
using automatic network analyzer techniques and error correction

PROPOSED STABILITY DATE: 2028
NOTE FROM TC/SC OFFICERS:
download this electronic file, to make a copy and to print out the content for the sole purpose of preparing National
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IEC CDV 60444-11 © IEC 2025 – 2 – 49/1489/CDV
1 CONTENTS
3 FOREWORD . 4
4 INTRODUCTION . 6
5 1 Scope . 7
6 2 Normative references . 7
7 3 Terms and definitions . 7
8 4 General concepts . 8
9 4.1 Load resonance frequencies f and f . 8
Lr La
10 Effective load capacitance C . 9
4.2 Leff
11 5 Reference plane and test conditions . 9
12 5.1 General . 9
13 5.2 Principle of measurement . 9
14 5.3 Evaluation of errors. 12
15 5.3.1 General comments . 12
16 5.3.2 Accuracy of measurement . 12
17 5.3.3 Reproducibility . 13
18 5.3.4 Comparison with the manual method . 15
19 5.3.5 Limitations . 15
20 Annex A (informative) Manual measuring method of the load resonance frequency f ,
L
21 load resonance resistance R using physical load capacitance . 16
L
22 A.1 General . 16
23 A.2 Measuring circuit . 16
24 A.2.1 The measuring circuit of a zero phase -network system . 16
25 A.2.2 An outline description . 16
26 A.2.3 Load capacitor specification . 16
27 A.3 Method of measurement . 17
28 A.3.1 Initial adjustment . 17
29 A.3.2 The method for the measurement of load resonance frequency and
30 resistance . 17
31 A.4 Load capacitor design . 17
32 A.4.1 Mechanical features . 17
33 A.4.2 Insertion into -network . 18
34 A.4.3 Calibration and measurement of load capacitors . 20
35 A.5 Measurement errors . 21
36 A.5.1 General . 21
37 A.5.2 Main sources of measurement errors . 21
38 A.5.3 The effects of the frequency/temperature characteristics of the crystal
39 unit . 22
40 A.5.4 The accuracy of the frequency measurements . 22
41 A.6 Analysis of errors . 22
42 A.6.1 Measurement error of load resonance frequency f . 22
L
43 A.6.2 Measurement error of load resonance resistance R . 22
L
44 A.6.3 Measurement errors of C . 23
45 Bibliography . 27

IEC CDV 60444-11 © IEC 2025 – 3 – 49/1489/CDV
47 Figure 1 – Admittance of a quartz crystal unit . 8
48 Figure 2 – X as a function of frequency (solid line) in the vicinity of f . 11
C L
49 Figure 3 – Level of drive of a crystal in a -network vs. frequency . 11
50 Figure 4 – Error of the load resonance frequency due to the inaccuracy of the
51 measured voltages (dashed line) and the calibration resistances (soft line) . 13
52 Figure 5 – C -error resulting from f error (due to inaccuracy of the measured voltages
L L
53 and the calibration resistances) for the same crystal as in Figure 4. 13
54 Figure 6 – Frequency error due to noise of the measured voltages . 14
55 Figure 7a – Error of load resonance frequency f at 30 pF for typical equivalent
L
56 parameters of quartz crystal units . 14
57 Figure 7b – Error of load resonance frequency f at 10 pF for typical equivalent
L
58 parameters of quartz crystal units . 15
59 Figure A.1 – Typical load capacitor with carrier . 18
60 Figure A.2 – Method of insertion of load capacitor into -network . 19
61 Figure A.3 – Circuit diagram of -network including load capacitor C . 20
L
62 Figure A.4 – Load capacitance inaccuracy as a function of frequency, for a load
63 capacitance of 30 pF inclusive of calibration inaccuracy and residual inductance
64 effects (Worst case situation) . 21
65 Figure A.5 – Relative measurement error of f versus crystal pulling sensitivity for
L
66 various frequencies at a load capacitance of 30 pF . 22
67 Figure A.6 – Relative measurement error of R versus frequency, for various values of
L
68 C . 23
L
69 Figure A.7 – Relative measurement error of C as a function of frequency. 24
70 Figure A.8– Relative measurement error of C as a function of C for various
1 1
71 frequency measurement errors C = 5 pF; C = 15 pF; C = 30 pF . 25
o L1 L2
72 Figure A.9 – Relative measurement error of C as a function of C for various values
1 1
73 of quality factor Q C = 3 pF; C = 15 pF; C = 30 pF . 26
o L1 L2
IEC CDV 60444-11 © IEC 2025 – 4 – 49/1489/CDV
75 INTERNATIONAL ELECTROTECHNICAL COMMISSION
76 ____________
78 MEASUREMENT OF QUARTZ CRYSTAL UNIT PARAMETERS
80 Part 11: Standard method for the determination of the load resonance
81 frequency 𝒇 and the effective load capacitance 𝑪 using automatic
L Leff
82 network analyzer techniques and error correction
84 FOREWORD
85 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
86 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
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93 Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
94 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
95 consensus of opinion on the relevant subjects since each technical committee has representation from all
96 interested IEC National Committees.
97 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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111 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
112 Publications.
113 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
114 indispensable for the correct application of this publication.
115 9) IEC draw attention to the possibility that the implementation of this document may involve the use of (a) patent(s).
116 IEC take no position concerning the evidence, validity or applicability of any claimed patent rights in respect
117 thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which may
118 be required to implement this document. However, implementers are cautioned that this may not represent the
119 latest information, which may be obtained from the patent database available at https://patents.iec.ch [and/or]
120 www.iso.org/patents. IEC shall not be held responsible for identifying any or all such patent rights.
121 IEC 60444-11 has been prepared by IEC technical committee 49: Piezoelectric, dielectric and
122 electrostatic devices and associated materials for frequency control, selection and detection . It
123 is an International Standard.
124 This second edition cancels and replaces the first edition published in 2010. This edition
125 constitutes a technical revision.
126 This edition includes the following significant technical changes with respect to the previous
127 edition.
128 a) Key contents of withdrawn IEC TR 60444-4 are reproduced as Annex A.
129 b) Some formula in the first edition have been corrected.

IEC CDV 60444-11 © IEC 2025 – 5 – 49/1489/CDV
130 The text of this International Standard is based on the following documents:
Draft Report on voting
XX/XX/FDIS XX/XX/RVD
133 Full information on the voting for its approval can be found in the report on voting indicated in
134 the above table.
135 The language used for the development of this International Standard is English.
136 This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
137 accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
138 at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
139 described in greater detail at www.iec.ch/publications.
140 The committee has decided that the contents of this document will remain unchanged until the
141 stability date indicated on the IEC website under webstore.iec.ch in the data related to the
142 specific document. At this date, the document will be
143 • reconfirmed,
144 • withdrawn,
145 • replaced by a revised edition, or
146 • amended.
IEC CDV 60444-11 © IEC 2025 – 6 – 49/1489/CDV
150 INTRODUCTION
151 This part of IEC 60444 defines the measuring method of load resonance frequency fL using
152 automatic network analyzer techniques.
153 At the same time, though the standard for manual measuring method specified by IEC TR
154 60444-4 has been withdrawn, the main contents of manual measuring method remain as Annex
155 A for user’s convenience. However, in case of dispute, the standard method as described below
156 shall be used as reference.
157 The figure of merit M, according to Table 1 of IEC 60122-1:2002, is expressed in the following
158 equation:
𝑄 1
159 𝑀 = = (1)
𝑟 𝜔𝐶 𝑅
0 1
160 This gives good results in a frequency range up to 200 MHz. This method allows the calculation
161 of load resonance frequency offset f , frequency pulling range f f and pulling sensitivity
L L1, L2
162 S as described in 2.2.31 of IEC 60122-1: 2002.This measurement technique avoids the use of
163 physical load capacitors, and allows higher accuracy, better reproducibility and correlation to
164 the application. It extends the upper frequency limit from 30MHz by the manual method to
165 200MHz approximately. This method is based on the error-corrected measurement technique
166 of IEC 60444-5:1995, and therefore allows the measurement of f and C together with the
L Leff
167 determination of the equivalent crystal parameters in one sequence without changing the test
168 fixture.
169 With this method the frequency f is searched where the reactance X of the crystal has the

L C
170 opposite value of the reactance of the load capacitance.
171 𝑋 = −𝑋 = (2)
𝐶 𝐶𝐿
𝜔 𝐶
𝐿 𝐿
172 Furthermore, this method allows to determine the effective load capacitance C at the nominal
Leff
173 frequency f .
nom
IEC CDV 60444-11 © IEC 2025 – 7 – 49/1489/CDV
175 MEASUREMENT OF QUARTZ CRYSTAL UNIT PARAMETERS
177 Part 11: Standard method for the determination of the load resonance
178 frequency 𝒇 and the effective load capacitance 𝑪 using automatic
L Leff
179 network analyzer techniques and error correction
183 1 Scope
184 This part of IEC 60444 defines the standard method of measuring load resonance frequency f
L
185 at the nominal value of C , and the determination of the effective load capacitance C at the
L Leff
186 nominal frequency for crystals with the figure of merit M  4.
187 2 Normative references
188 The following documents are referred to in the text in such a way that some or all of their content
189 constitutes requirements of this document. For dated references, only the edition cited applies.
190 For undated references, the latest edition of the referenced document (including any
191 amendments) applies.
192 IEC 60122-1:2002, Quartz crystal units of assessed quality – Part 1: Generic specification
193 IEC 60122-1 Amd.1(2017), Amendment 1 - Quartz crystal units of assessed quality - Part 1:
194 Generic specification
195 IEC 60444-1 (1986): Measurement of quartz crystal unit parameters by zero phase technique
196 in a π‐ network. Part l: Basic method for the measurement of resonance frequency and
197 resonance resistance of quartz crystal units by zero phase technique in a π-network
198 IEC 60444-2 (1980): Part 2: Phase offset method for measurement of motional capacitance of
199 quartz crystal units
200 IEC 60444-5:1995, Measurement of quartz crystal units parameters – Part 5: Methods for the
201 determination of equivalent electrical parameters using automatic network analyzer techniques
202 and error correction
203 3 Terms and definitions
204 For the purposes of this document, the terms and definitions given in IEC 60122-1 apply.
205 ISO and IEC maintain terminology databases for use in standardization at the following
206 addresses:
207 • IEC Electropedia: available at https://www.electropedia.org/
208 • ISO Online browsing platform: available at https://www.iso.org/obp
IEC CDV 60444-11 © IEC 2025 – 8 – 49/1489/CDV
210 4 General concepts
211 4.1 Load resonance frequencies f and f
Lr La
212 As can be seen in Figure 1, there are two intersection frequencies where XX=− , f with
C CL Lr
213 high admittance (low impedance) and f with low admittance (high impedance).
La
214 The load resonant frequency f is one of the two frequencies of a crystal unit in association with
L
215 a series or with a parallel load capacitance, at which the electrical admittance (respectively
216 impedance) of the combination is resistive. The load resonance frequency f is the lower of the
L
217 two frequencies.
218 In a first approximation f can be calculated by:
L
𝑓 =
(3)
s
2𝜋 𝐿 𝐶
√
1 1
𝐶
𝑓 ≈ 𝑓 ∙ (1 + ) (4)
L S
( )
2 ∙ 𝐶 + 𝐶
0 L
f
fm
f
s
  C
Conductance
fr
fa
  CL
f
La f
Lr
R
R
r
2R1
IEC  2353/10
220 NOTE f is load resonance frequency that commonly expressed f .
Lr L
221 Figure 1 – Admittance of a quartz crystal unit
Susceptance
IEC CDV 60444-11 © IEC 2025 – 9 – 49/1489/CDV
223 Effective load capacitance C
4.2 Leff
224 C is defined by the reactance of the crystal at the nominal frequency
Leff
𝐶 = (5)
Leff
( )
𝜔 𝑋 𝜔
nom C nom
225 5 Reference plane and test conditions
226 5.1 General
227 Reference plane: as in 8.4 of IEC 60444-5:1995.
228 Test conditions: crystal case not grounded.
229 Level of drive: the output level of the generator is set, such that at its (series) resonance
230 frequency, the crystal under test is measured at the nominal drive level.
231 The measurement at the load resonance frequency using the method described below leads to
232 a level of drive, which is remarkably lower than at the (series) resonance frequency due to the
233 relative high reactance value. Therefore, a correction measurement is performed, for details
234 see 5.2.
235 5.2 Principle of measurement
236 The principles of measurement are the following.
237 a) Calibration
238 Due to the high impedance measurements with this method special care has to be taken in
239 the calibration of the test set-up.
240 Similar to IEC 60444-5:1995, use the following three known calibration elements:
241 1) short-circuit (0 ) or resistor with low resistance;
242 2) resistor of 25  or 50  nominal;
243 3) open circuit (infinite resistance) or capacitor of 10 pF nominal;
244 b) Calibration with three known calibration elements:
245 1) short-circuit calibration;
246 2) calibration load (25  or 50 );
247 3) open circuit calibration (or calibration capacitor of 10 pF);
( ) ( ) ( )
𝑍 𝑍 𝑉 𝑉 +𝑍 𝑍 𝑉 −𝑉 +𝑍 𝑍 𝑉 −𝑉
1 2 1− 2 2 3 2 3 3 1 3 1
248 𝑅 = (6)
T
( ) ( ) ( )
𝑍 𝑉 −𝑉 +𝑍 𝑉 −𝑉 +𝑍 𝑉 −𝑉
1 2 3 2 3 1 3 1 2
( ) ( ) ( )
𝑉 𝑍 𝑍 𝑉 𝑉 +𝑉 𝑍 𝑍 𝑉 −𝑉 +𝑉 𝑍 𝑍 𝑉 −𝑉
3 1 2 1− 2 1 2 3 2 3 2 3 1 3 1
249 𝑉 = (7)
S
𝑍 𝑍 (𝑉 −𝑉 )+𝑍 𝑍 (𝑉 −𝑉 )+𝑍 𝑍 (𝑉 −𝑉 )
1 2 1 2 2 3 2 3 3 1 3 1
( ) ( ) ( )
𝑍 𝑉 𝑉 𝑉 +𝑍 𝑉 𝑉 −𝑉 +𝑍 𝑉 𝑉 −𝑉
1 1 2− 3 2 2 3 1 3 3 1 2
250 𝑉 = (8)
( ) ( ) ( )
𝑍 𝑉 −𝑉 +𝑍 𝑉 −𝑉 +𝑍 𝑉 −𝑉
1 2 3 2 3 1 3 1 2
251 where
252 Z is the impedance of calibration element 1
IEC CDV 60444-11 © IEC 2025 – 10 – 49/1489/CDV
253    Z is the impedance of calibration element 2
254  Z is the im
...