Accuracy, stability and related electrical parameters of active crystal oscillator
The accuracy of active crystal oscillator can reach :
±0.2PPM, ±0.5PPM, ±1PPM, ±2PPM, ±5PPM, ±10PPM, ±20PPM and ±30PPM.
As the specific design objectives and requirements of electronic products are different,
the accuracy of the selected active crystal oscillator is also different.
For example, in the selection of crystal oscillator for an electronic product with GPS positioning,
it is recommended that the crystal oscillator accuracy should be at least within ±10PPM.
The stability of active crystal oscillator is as follows:
① The working temperature is in the range of -20 ℃ ~ + 70 ℃, and the stability can be controlled
in the range of ±20ppm ~ ±30ppm.
② The working temperature range (- 40 ℃ ~ + 85 ℃) and the stability can be controlled at ±25ppm.
③ In the active crystal oscillator series, the stability of temperature TCXO and VCXO can be controlled
at ±0.5ppm or even lower.
Parameters and analysis:
① The total frequency difference of crystal oscillator includes the maximum frequency difference caused by
frequency temperature stability, frequency temperature accuracy, frequency aging rate,
frequency power supply voltage stability and frequency load stability.
② Start-up characteristic (frequency stable preheating time): refers to the rate of change from the frequency of
a period of time（five minutes ) after start-up to that of another period of time (one hour）after start-up,
indicating that the crystal oscillator reaches a stable speed.
③ Frequency aging rate: the aging rate of crystal oscillator refers to the aging degree of crystal oscillator in years, expressed by PPM.
For example, the aging rate of quartz crystal resonators and quartz crystal oscillators produced by XTALONG
can be controlled within the maximum ±3ppm/ years. Based on the difference of the working environment of the crystal oscillator,
the aging frequency shift direction of the crystal oscillator is generally different. Relatively speaking,
the aging rate of the crystal oscillator will be relatively high in the first year of use, and then gradually tend to be stable.