Understanding quartz crystals and oscillators

325 Pages·2014·3.63 MB·English

by  Cerda, Ramón M.

Understanding Quartz Crystals
and Oscillators
For a complete listing of titles in the
Artech House Microwave Library,
turn to the back of this book.
Understanding Quartz Crystals
and Oscillators
Ramón M. Cerda
Library of Congress Cataloging-in-Publication Data
A catalog record for this book is available from the U.S. Library of Congress.
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library.
Cover design by Igor Valdman
ISBN 13: 978-1-60807-118-0
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10 9 8 7 6 5 4 3 2 1
To my kids, Cynthia, Ricardo, and Christian.

Contents
Preface xxi
Acknowledgments xxiiI
1 Quartz Crystals 1
1.1 Introduction 1
1.2 Mother Nature Used Quartz First 2
1.3 The Curie Brothers 3
1.4 Piezoelectricity 3
1.5 Quartz 4
1.6 Left-Handed and Right-Handed Quartz 5
1.7 Quartz Is Anisotropic 5
1.8 A Timeline of Quartz Crystals and Oscillators 6
1.9 Important Definitions 7
1.9.1 Time 7
1.9.2 Second 7
1.9.3 Frequency 8
1.9.4 Nominal Frequency 8
1.9.5 Clock 9
vii
viii Understanding Quartz Crystals and Oscillators Contents ix
1.9.6 Room Frequency or 25°C Frequency 9
1.9.7 Fractional Frequency 9
1.9.8 Allan Deviation 10
1.9.9 Accuracy, Precision, and Stability 10
1.9.10 Accuracy 10
1.9.11 Precision 12
1.9.12 Stability 12
1.9.13 Frequency Stability 12
1.9.14 Short-Term Frequency Stability 12
1.9.15 Medium-Term Frequency Stability 12
1.9.16 Long-Term Frequency Stability 12
1.9.17 Aging and Drift 12
1.9.18 Ambient Temperature 13
1.9.19 Frequency-Temperature Stability (Frequency
Versus Temperature Stability) 13
1.9.20 Tolerance 13
1.9.21 Calibration 13
1.9.22 Jitter 13
1.9.23 Oscillator 14
1.9.24 Phase Shift 14
1.9.25 Phase Noise 14
1.9.26 Resonance 14
1.9.27 Resonance Frequency 14
1.9.28 Quality Factor, Q 14
1.9.29 Resonator 14
1.9.30 Quartz Crystal 15
1.9.31 Quartz Crystal Oscillator 15
1.9.32 Random Deviations 15
1.9.33 Systematic/Deterministic Deviations 15
1.9.34 Uncertainty 15
1.10 Frequency Stability in Perspective 15
1.11 Growing Quartz 15
1.12 Swept Quartz 17
1.13 A Crystal Is Born 18
1.14 Inside the Crystal Unit 19
1.14.1 The Glass Seals 20
1.14.2 The Conductive Epoxy Cement 20
1.15 Sealing the Crystal Unit 21
viii Understanding Quartz Crystals and Oscillators Contents ix
1.15.1 Solder Seal 21
1.15.2 Resistance Weld 21
1.15.3 Cold Weld 21
1.15.4 Seam Weld 21
1.15.5 Epoxy Seal 22
1.16 Testing for Moisture 22
1.17 Crystal Resonator Mechanical Equivalent Model 22
1.18 Crystal Resonator Electrical Equivalent Circuit 22
1.19 Derivation of Equivalent Circuit Equations 24
1.20 Series-Resonant and Parallel-Resonant Oscillators 26
1.20.1 Definitions of Series and Parallel Crystals 26
1.21 Load Capacitance 27
1.22 Fundamental Mode Crystals 28
1.23 Overtone Mode Crystals 28
1.24 Spurious Modes 29
1.25 Expanded Quartz Resonator Equivalent Circuit Model 29
1.26 The Ideal Phase Angle of the Quartz Crystal Resonator 30
1.27 Pulling the Crystal Frequency by Changing the
Load Capacitance 31
1.28 Zero-to-Pole Spacing 33
1.29 Trim Sensitivity 34
1.30 Important Unitless Quantities 37
1.31 Resistance of the Crystal Above Series Resonance (ESR) 38
References 39
2 Quartz Crystal Characteristics 41
2.1 Introduction 41
2.2 Defining the Frequency Versus Temperature Curve 41