| Terminology |
Description |
| Frequency |
The
main component and purpose of a crystal. Cycles per second generated
or Hz.
This Parameter is usually specified in MegaHertz(MHz) |
| Crystal
element |
Piezoelectric
material cut to a given geometric shape, size and orientation with
respect to the crystal lographics axes of the crystal. |
| Electrode |
An
electrically conductive film in contact with the surface of a crystal
element, of which an electrical field is applied to the element. |
| Load
capacitance (CL) |
The
value of the external load needed in order for the crystal to run
at optimal operation.
Specified in pico Farads (pF) |
| Crystal
unit equivalent Circuit |
The
electrical circuit which has the exact impedance as the unit in the
immediate neighborhood of resonance. |
| Resonance
frequency (fr) |
The
lower of the two frequencies of the crystal unit, at which the electrical
impedance of the crystal unit is resistive( under specified conditions
) |
| Load
resonance frequency (fL) |
One
of the two frequencies of a crystal unit, similar with a series or
parallel load capacitance, under specified conditions, at which the
electrical impedance of the combination is resistive.
The frequency is the lower of the two frequencies when the load capacitance
is in series. |
| ESR
series resonant resistance (R1) |
Vibration
loss to the (equivalent) internal resistance component of the crystal
resonator, at the series resonant frequency. A measure of the easiness
of oscillation. |
| Load
resonance resistance (RL) |
The
resistance of the crystal unit in series with a stated external capacitance
at the load resonance frequency. |
| Motional
capacitance |
The
capacitance of the motional (series) arm of the equivalent circuit. |
| Shunt
Capacitance (C0) |
Charge
capacitance between the two electrodes in the crystal oscillator. |
| Capacitance
ratio (C0/C1) |
The
ratio of the shunt capacitance is to the motional capacitance. |
| Overtone
order |
The
numbers allocated to the successive overtones of a given mode of vibration
from the integral numbers commencing with the fundamental as unity.
|
| Tolerance |
The
accuracy of the crystal at 25℃, a parameter needed to allow for error
in quartz manufacturing process. Specified in parts per million (ppm) |
| Operating
temperature range |
The
range of temperatures over, which the crystal unit shall function
within the specified tolerances. |
| Storage
temperature range |
The
temperature ranges over the standard characteristics of the crystal
unit can be maintained.
When the crystal unit is not in operation. |
| Drive
Level |
Maximum
power rating of crystal. Specified in max milliWatts(mW). Exceeding
this rating could damage the crystal. |
| Aging |
Amount
of frequency drift when operated under the specified conditions for
a specified term. |
| Soldering
conditions |
Soldering
conditions that can be assured at mounting. Temperature or times over
these limits may result in characteristic degradation or destruction. |
| Insulation
resistance |
Resistance
between lead and lead, or between lead and case package. |
| Q
value |
In
a resonance circuit composed of an L, C and R, a quantity that represents
the sharpness of a resonance curve. A curve that shows the relationship
between the circuits current and the power frequency. |
| Frequency
stability |
Within
operating temperature, the operating voltage and output load range,
deviate in actual frequency from nominal frequency. |
| Supply
current |
The
electric current to supply (VVD) pin with no output load, when the
output is enabled. |
| Duty |
The
1/2 to 1 cycle ratio (as expressed in percentage), of an output waveform
at the specified voltage level. |
| Output
load |
The
load that can be connected to the oscillator. |
| Rise
time |
The
time interval required for the leading edge of a pulse waveform to
change from a specified L level to a specified H voltage level. |
| Start
up time |
The
time interval between power on and the supply voltage, the specified
voltage until the output waveform becomes stabilize. |
| Output
enable function |
The
function to change the output signal.
When pins OE are at H level or open: The specified frequency is output.
(Enable)
When pins OE are at L level or open: The output has high impedance.
(Disable) |
