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Nominal Frequency |
32.768kHz |
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The specified reference or "center" frequency of the crystal.
Typically specified in megahertz (MHz)or kilohertz (kHz).
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Frequency Tolerance |
±20ppm at 25°C |
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The amount of frequency deviation from a specified center frequency
at ambient temperature (referenced at 25°C). This parameter is specified with a
maximum and minimum frequency deviation, expressed in percent (%) or parts per million
(ppm). This deviation is associated with a set of operating conditions including: Load
Capacitance and Drive Level.
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Frequency Stability |
-0.042ppm/(change in °C)2 Maximum, Parabolic; Turn over temperature at 25°C ±5°C |
|
The amount of frequency deviation from the ambient temperature
frequency over the operating temperature range. This deviation is associated with
a set of operating conditions including: Operating Temperature Range, Load Capacitance,
and Drive Level. This parameter is specified with a maximum and minimum
frequency deviation, expressed in percent (%) or parts per million (ppm).
The frequency stability is determined by the following primary factors:
Type of quartz cut and angle of the quartz cut. Some of the secondary factors
include: mode of operation, drive level, load capacitance, and mechanical design.
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Operating Temperature Range |
-10°C to +60°C |
|
The maximum and minimum temperatures that
the crystal device can be exposed to during oscillation.Over this
temperature range,all of the specified device operating
parameters are guaranteed.
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| Load Capacitance |
12.5pF |
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Equivalent Series Resistance (ESR) |
35,000 Ohms Maximum |
|
The resistive element, measured in ohms, of a crystal device. At the frequency found in
Equation 1, the motional inductance
(L1)and motional capacitance (C1) are of equal ohmic value
but are exactly opposite in phase. The net result is that they cancel one another and only
a resistance remains in the series leg of the equivalent circuit. The ESR measurement is made only at the series
resonant frequency (FS), not at some predetermined parallel resonant frequency
(FL). Crystal resistance measured at some parallel load resonant frequency is
often called the "effective" resistance.
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|
Shunt Capacitance |
0.85pF Typical, 2pF Maximum |
|
The static capacitance between the crystal
terminals. Measured in picofarads (pF), Shunt Capacitance is present
whether the device is oscillating or not (unrelated to the piezoelectric
effect of the quartz). Shunt Capacitance is derived from the
dielectric of the quartz, the area of the crystal electrodes,
and the capacitance presented by the crystal holder.
|
|
| Motional Capacitance |
2.0fF Typical |
|
Storage Temperature |
-20°C to +70°C |
|
The minimum and maximum temperatures that the device can
be stored or exposed to when in a non-oscillation state. After exposing or
storing the device at the minimum or maximum temperatures for a length of
time, all of the operating specifications are guaranteed over the specified
Operating Temperature Range.
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|
Drive Level |
1 µWatt Maximum |
|
A function of the driving or excitation current flowing
through the crystal. The Drive Level is the amount of power dissipation in
the crystal, expressed in microwatts or milliwatts. Maximum power is the most
power the device can dissipate while still maintaining operation with all
electrical parameters guaranteed. Drive level should be maintained at the
minimum levels necessary to initiate proper start-up and assure steady state
oscillation. Excessive drive level can cause poor aging characteristics and
crystal damage.
|
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Aging (at 25°C) |
±3ppm/year Maximum |
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The systematic change in frequency with time due to internal changes in the crystal. Aging
is often expressed as a maximum value in parts per million per year [ppm/yr]. The rate of
aging is typically greatest during the first 30 to 60 days after which time the aging rate
decreases. The following factors effect crystal aging: adsorption and desorption of
contamination on the surfaces of the quartz, stress relief of the mounting and bonding
structures, material outgassing, and seal integrity.
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| Insulation Resistance |
500 Megaohms Minimum at 100Vdc |
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