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Synthetic Quartz Crystal

Standard Specifications

· Angular Deviation of the reference surface.
· Angular Deviation of Z surface from X axis:0°00'±30' :1°30'±30'
· Angular Deviation of the minus X surface from Y axis :0°00'±15'
· Angular Deviation of the minus X surface from Z axis :0°00'±15'
· Angular Deviation of Z surface from Y axis :0°00'±15'

The standard dimension of Lumbered

X-Axis:±0.2mm Z-Axis: ±0.2mm

Pure Lumbered ZY-Bar Seed Orientation?=0°

Please consult with us for other dimensions and angles.

Pure Lumbered Z-Plate Seed Orientation?=0°, 1.5°

Please consult with us for other dimensions and angles.

Explanation of Crystal Units

The crystal unit is an electronic device that is capable of composing a frequency generator circuit with an extremely high stability. It has achieved high degree of compactness and high performance, along with the progress of other electronic components

1 Equivalent Circuit
Vibration of a crystal unit is actually mechanical vibration. However, the crystal unit can be expressed by a two terminal network if its behavior is electrically converted. The series circuit consisting of L1, C1, and R1 is related to elastic vibration, while the element C0 connected in parallel to the series arm as a capacitance attributable to the dielectric body of a quartz crystal plate. The resistance R1 is a resonance resistance of the crystal unit at the series resonance frequency. (See Fig.1.)

2 Frequency-Temperature
Characteristics of an AT-cut The frequency-temperature characteristics of an AT-cut crystal unit most generally used at present are expressed by cubic curves. (See Fig.2.) A crystal plate is cut at an angle at which a required frequency tolerance is obtained in the given operating temperature range. Actually, however there can be some dispersion in apparent cutting angle due to the result of cutting and polishing accuracy in the successive processes. Therefore, it is necessary to raise processing accuracy.

3 Level of Drive
Since a crystal unit performs mechanical vibration, too much vibration may lead to unstable oscillation frequency, and finally to destruction in the worst case. When designing an oscillation circuit, the level of drive should be examined so as to use an oscillator below the level specified by our company. Fig.3 shows an example method of confirming a level of drive. The method employs a current probe to measure the crystal oscillator current. In this case the level of drive is as follows:

4 Load Capacitance
The load capacitance CL is a factor for determining the "conditions" of a crystal unit when used in the oscillation circuit. In an ordinary oscillation circuit, the crystal unit is used in a range where it functions as an inductive reactance. In such usage, the oscillation circuit operates as a capacitive reactance. In other words, when the oscillation circuit is seen from both terminals of the crystal unit, the oscillation circuit can be expressed as a series circuit of a negative resistance -R and a capacitance CL. At that time this capacitance is called the load capacitance. The relationship between load capacitance and oscillation frequency is not linear. When the load capacitance is small, the amount of frequency variation is large, and when the load capacitance is increased, frequency variation lowers. If the load capacitance is lessened in the oscillation circuit to secure a large allowance for the oscillation frequency, the frequency stability will be greatly influenced even by a small change in the circuit. The load capacitance can be chosen from standard values specified in the catalog.

5 Equivalent Circuit of Crystal Oscillation Circuit
When a crystal unit is actuated as an inductive reactance in an oscillation circuit, the relationship between crystal unit and oscillation circuit is shown in Fig.4. To improve the starting conditions of the oscillation circuit, it is preferable to increase the value of negative resistance -R which parameter of the oscillation circuit. The starting conditions will become worse if a circuit without much allowance in negative resistance (less negative resistance) is combined with a crystal unit having a larger resonance resistance. The oscillation circuit should be designed to a goal such that the value of negative resistance is 5 to 10 times the resonance resistance. It is also necessary that the center value of load capacitance (to determine the absolute value of oscillation frequency) and the variable range (fine adjustment range of oscillation frequency) are maintained at the optimum values in the oscillation circuit.

6 Oscillation circuit
A typical oscillation circuit composed of a crystal unit is introduced below. Element constants used are for example.

(1) Crystal units are designed to have lower limitable level of drive, of 100µW and below. Prior to use, the crystal current should be examined in an actually mounting circuit. (See Fig.3.)
(2) The negative resistance of a circuit must be checked. Confirmation of negative resistance is possible according to Fig.6. A goal of negative resistance is designed to 5 or more times of the resonance resistance.
(3) The Rd in the circuit diagram is indispensable when used in a C-MOS oscillation circuit. (See Fig.5.) If this Rd is attached, the level of drive is kept within the specified value and stable oscillation frequency can be obtained.
(4) Cg and Cd should be used within the range of 10 ? 30 pF. If Cg and Cd are used below 10 pF or above 30 pF, oscillation may be easily affected by circuit performance, level of drive may increase, or negative resistance may decrease, thus failing in maintaining stable oscillation.
(5) The layout for crystal oscillation circuits should be arranged as short as possible. The stray capacitance between circuits and ground patterns should be reduced. Crossing of crystal oscillation circuits patterns over other circuit patterns should be avoided.
(6) If the circuits used, IC types, and IC manufacturers are different, frequency, level of drive, and negative resistance should be confirmed.
:: Overtone oscillation circuits need additional consultation.

7 Notes for Crystal Unit Applications
(1) It has the possibility that a crystal element fractures when an excessive shock and a vibration more than the regulation are added at the time of the conveyance or circuit board mounting. Be sure to do characteristic confirmation when a shock more than the regulation, a vibration are added.
(2) Ultrasonic-wave cleaning may cause deterioration of crystal units, which printed in the catalog.
(3) Leave it and bend 0.5 or more mm from the foundation of the lead in the case of lead type.
(4) The deformation of the extreme circuit board sometimes brings about a pattern comes off, a terminal and electrode comes off, a crack in the solder. Be careful when you install it in the position where the curve of the circuit board appears greatly when you divide a circuit board after you mount it specially.
(5) Select the model whose shock is small as much as possible, and use it after confirmation in advance when you use an automatic loading machine.

8.Recommend reflow temperature profile

Taping and Reel Specifications

Tape

Reel

Glossary

Aging
It is the Change of nominal frequency and / or the resistance of a quartz crystal unit through the time.

Angle
It is the angle at which a resonator plate is cut from the quartz stone in relation to the original crystallographic axes. The angle of cut is critical to the performance of the crystal unit, particularly for frequency deviation over a temperature range.

AT cut
The commercial designation for a specifically oriented resonator plate, having desirable and repeatable operating characteristics. The "AT cut" is the most popular thickness-shear crystal unit manufactured today.

AT Strip
AT-cut crystal but in the shape of a rectangular strip. It has a higher ESR than a round AT-cut crystal but is smaller in size, thus allowing smaller crystal packages.

Axis Direction in quartz stone. The plural is "axes."

Base
Base is the lower portion of a crystal holder. The base incorporates a resonator mounting structure and leads or pins to connect the device to an external circuit. Please also refer to "Holder."

Bevel
Modification to one or both of the major faces of a resonator plate, in which the face is altered for a partially spherical configuration. Please also refer to "Contour."

Blank Quartz resonator plate. Also known as "wafer," "plate," or "resonator."

BT cut Commercial designation for a specifically oriented resonator plate, having well known and repeatable characteristics. "AT-cut" is more popular than "BT-cut"

C0
Also known as "Shunt Capacitance."

C1
Also known as "Motional Capacitance." Often also abbreviated as "Cm."

Capacitance
Property exhibited by two conductors separated by a dielectric where an electric charge becomes stored between the conductors. Measured in "farads" and identified with the letter "C."

Capacitor Passive electronic circuit component in its simplest form; consists of two metal electrodes separated by a dielectric.

Can
Please refer to "Cover"

C.I.
Abbreviation for "crystal impedance," sometimes also known as "resistance."

C.I.M.
Abbreviation for "crystal impedance meter." Please refer to "Test Set"

Cold Weld
Consist of a procedure in which the base and can are dissimilar metals that are pressed together to form one metal.

Contour
Modification to one or both of the major faces of a resonator plate, where the face is altered to have a completely spherical configuration. Please also refer to "Bevel."

Coupled Mode
An unwanted mode that is energized at the same frequency as the wanted mode; thus, draining energy from the desired mode.

Cycle
A complete repetition of an event

Deviation
Amount by which a quantity differs from its nominal value. In this case, the amount by which a frequency differs from the nominal or specified frequency.

Dew Point
The temperature at which components of a gas material starts to condense into liquid.

Dip
Term used to describe a sudden increase of activity, followed by a return to the previous level of the activity of a crystal unit.

Drive Level
Amount of power dissipated by the oscillating crystal unit. Expressed in terms of mW.

Equivalent Circuit
Vibration of a crystal is actually a mechanical vibration. However, the crystal unit can be expressed by two terminal networks if its behavior is electrically converted. The series circuit consisting of L1, C1 & R1 is related to elastic vibration, while the element C0 is connected in parallel to the series arm as a capacitance attributable to the dialectic body of a quartz crystal plate. The resistance R1 is a resonance resistance of the crystal unit at the series resonance frequency.

ESR
It is the abbreviation for "Equivalent Series Resistance." A crystal unit has a resistive element. This term is required to define and quantify that characteristic.

Etch
A process crystal manufacturers use to improve the surface condition of a crystal and to increase the frequency of a blank. The word "etch" is used to describe the material used in the etch process, as well as the process itself.

Frequency
It is a periodic repetition of an event within a unit of time. In an electrical circuit, it is the number of waves that pass through a given point in one second. In other words, it is the number of times a resonator plate oscillates or vibrates in one second. The customer usually specifies the nominal or desired frequency.

Frequency Stability
The acceptable deviation usually represented in parts per million (PPM), over a specified temperature range. Deviation is referenced to the measured frequency at +25? C.

Frequency Tolerance
The acceptable deviation from nominal frequency usually represented in parts per million (PPM), at a specific temperature, usually +25? C.

Fundamental
Lowest frequency a resonator plate will oscillate. Usually set by the physical dimensions of the plate.

Geometry
Shape of the resonator plate in a crystal unit. There are 3 geometrical forms available: Flat, Contoured, and Beveled.

Henry
Basic unit of inductance, represented by the letter "H." One henry of inductance is produced in a closed circuit by changing current uniformly at the rate of one Ampere per second.

Hertz (Hz)
Basic unit of measurement of frequency, "Hertz" used instead "cycle per second". Also used to denote one complete occurrence of an event in 1 second.

Impedance
Total opposition presented by a circuit or device to the flow of alternating current. Impedance is measured in "ohms", denoted by the letter "Z."

Inductance
In a conductor, or circuit, the inertial property that opposes the flow of current when a voltage is applied. Inductance is identified by the letter "L" and measured in "henries."

Inductor
Electronic component used to introduce inductance into a circuit.

Insulator
Any material that does not allow electricity to pass though easily

ISO
Abbreviation for "International Organization for Standardization."

Kilo
A prefix abbreviated "k," used to denote units of thousands. One "Kilo" is one thousand. In our industry, a frequency of one kilohertz is a frequency of one thousand hertz (cycles per second).

KHz
Abbreviation for "kiloHertz," used to describe the frequency of a crystal or oscillator in terms of thousands of Hertz (cycles per second).

Load Capacitance
It is the value of capacitance used in conjunction with the crystal unit. Load capacitance is a parameter normally set by the customer, typically expressed in pF (picoFarads).

Load Resonance
Term used to describe a crystal unit operating in conjunction with load capacitance.

Mega
Abbreviated with the capital letter "M," and used to denote units of millions, 106. One "Mega" is equal to one million. In this industry, one Mega hertz is a frequency of one million hertz (cycles per second).

Milli
Abbreviated "m," used to denote units of thousandths, 10-3. One "milli" is exactly the same as 1/1000th of a unit.

MHz
Abbreviation for "MegaHertz," describes the frequency of a crystal or oscillator in terms of millions of Hertz (cycles per second). A frequency denoted as "10.0 MHz" is the same as frequency of 10,000,000 Hertz (cycles per second).

Motional Capacitance
Abbreviated as "Cm" or "C1", it is the parameter associated with a quartz crystal unit, illustrates the electronic equivalence of the mechanical elasticity of the unit.

Motional Inductance
Abbreviated as "Lm" or "L1", it is the parameter associated with a quartz crystal unit, illustrates the electronic equivalence of the mechanical mass of the unit.

OEM
Abbreviation for "Original Equipment Manufacturer."

Operating Temperature Range
Temperature range at which the crystal's characteristics are guaranteed.

Oscillation Mode
A quartz crystal is designed to vibrate either on its fundamental frequency or one of its overtones. Deciding which oscillation mode to use becomes critical as frequency becomes higher. Fundamental vibration mode normally can go as high as 40MHz; although it may be more precise, cost can be an issue. Using overtones for high frequencies can be cost savings, however, it might not be as precise as desired.

Overtone
Odd numbered multiple of the fundamental frequency.

Package
Holder used to contain the crystal blank.

Parabolic Temperature Curve
BT-cut and Tuning Fork crystals' frequencies follow a parabolic curve over temperature. The frequency will change or decrease as the temperature goes above or below the turnover temperature.

Parallel Resonant
Oscillator circuit is normally uses a crystal unit that is designed to operate with a specified value of load capacitance. Resulting in a crystal frequency higher than the series resonant frequency, but lower than the true parallel resonant frequency.

PF
Abbreviation for "picoFarad," used to describe a fractional part 10-12, (one trillionth) of one Farad.

Pico
A prefix used to describe a sub-multiple of a number. One pico is one trillionth, 10-12, of a unit.

Plate
A quartz blank or resonator.

Polish
Polish is a term used to describe the process used in the manufacture of some types of quartz crystals. Which results in a very fine surface finish. Polish is also used to denote the material used in this process.

PPM
Abbreviation for "Parts Per Million," a method of calculation used to specify the acceptable frequency deviation of a crystal or oscillator.

Pullability
Change in frequency of a crystal unit; either from the natural resonant frequency (Fr) to a load resonant frequency (FL); or from one load resonant frequency to another. Frequency can be pulled in a parallel resonant circuit by changing the value of load capacitance.

Quartz
It is the crystalline form of Silicon Dioxide (SiO2). Material from which a blank is made.

Quartz Crystal Unit
A finished quartz crystal; consists of a resonator plate with electrodes, holder with suitable mounting structures, and a permanently sealed cover. Usually referred simply as a "crystal."

Reactance
Opposition to an alternating current presented by inductance, capacitance, or a combination of the two. Measured in "ohms" and denoted with the letter "X."

Resistance
The opposition to current flow in a circuit represented by the letter "R" and is measured in "ohms."

Resistance Weld
Procedure involving pressure sealing with electricity and back filling with nitrogen to force out oxygen and moisture. This process provides superior aging characteristics.

Resistor
Component used to introduce resistance into a circuit.

Resonant Frequency
Natural frequency at which a device vibrates. Abbreviated as "Frq" or "frq."

Resonance
Creation of vibrations in a system by applying periodic force; which is present when the frequency of the applied force is equal to the natural frequency of the system.

Resonator
Part that is capable of being set into resonance by the application of a periodic force.

Second
Basic unit of measurement of time, for our purposes, one "second" is 1/60th of a minute.

Series Resonance
Condition when a crystal unit is operated without the presence of load capacitance. "Series Resonance" is usually described as "series."

Shunt Capacitance
Parameter associated with a quartz crystal unit, used to denote capacitance resulting from the presence of the electrodes plus stray capacitance associated with the holder.

SMD
Abbreviation for "Surface Mount Device."

Spur
Substitution for the term "Spurious Frequency Response." Spur is used to describe a frequency occurring at some point higher than the desired mode but lower than the next overtone.

Tape and reel
A packaging style which, can accommodate automated pick & place equipment.

Test Set
Measures the frequency and resistance characteristic of a quartz crystal unit. Also referred as "crystal impedance meter," abbreviated as "C.I.M."

Trim Sensitivity
Measurement of the incremental fractional frequency change for an incremental change in the value of load capacitance. Trim sensitivity (S) is expressed in terms of PPM/pF and is calculated as follows:
Where (Ct) is the sum of the shunt capacitance (CO) and the load capacitance (CL).

Turnover Temperature
Temperature at which, the nominal frequency is at the up-most part of the parabolic curve.

Twinning
A condition within quartz stone where the optic and/or the electric axis suddenly reverse its natural order of polarity.

Volt
Basic practical unit of difference of (electrical) potential.