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Ceramic resonators stand between quartz crystal oscillators
and LC/RC oscillators in regards to accuracy. They are considerably
smaller, require no adjustments, with improved start-up time
and low cost.
Ceramic resonators come with standard, single-in-line package
(ZTB and ZTA Series), or 3-leads with built-in capacitors
(ZTT Series).
The oscillation of ceramic resonators is dependent upon mechanical
resonance associated with the their piezoelectric crystal
structure. These material (usually barium titanatae or lead-zirconium
titanate) have large dipole movement which causes the distortion
or growth of the crystal by an applied electric field.
The available frequency range varies from 190kHz to 25.000MHz.
The maximum allowable frequency deviation compared to the
measured frequency at 25°C over the temperature window,
I.e., -20°C to +80°C. The typical stability is ±0.3%
(±300ppm).
The allowable deviation from the nominal frequency at room
temperature. Frequency tolerance is expressed in percentage,
typical ±0.5% or in parts per millions (ppm), ±500ppm.
The value of impedance the crystal exhibits in the operating
resonant circuit.
The relative frequency change over a certain period of time.
This rate of change of frequencies normally exponential in
character. Typically, aging is ±0.5% over 10 years.
Load capacitance is the amount of capacitance that the oscillator
exhibits when looking into the circuit through the two resonator
terminals. Load capacitance is expressed in a pair of C1 and
C2 with the default values given in table format.
Its equivalent circuit is similar to the quartz crystal equivalent
circuit, I.e., consists of a series L1, C1, R1 circuit shunting
with a parallel CO capacitance. A standard ZTB-4.000MHz has
its typical parameters as follows: L-330uH, C1-5pF/CO-40pF
and Q-900.
TEL 949-366-8700 FAX 949-366-8707
specifications subject to change * revision 3-2003
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