What factors affect the frequency stability of crystal oscillator?
What factors affect the frequency stability oscillator?
frequency stability oscillator over temperature refers to the frequency shift relative to the reference temperature caused by the oscillator operating in the specified temperature range when other conditions remain unchanged.
Usually, the main function of crystal oscillator is to provide the clock signal source for the clock chip in the oscillation circuit,
so the frequency accuracy and frequency stability oscillator are regarded as the two most critical electrical parameters of crystal oscillator.
There are two aspects that will affect frequency stability of crystal oscillators.
One is the influence of working environment on crystal oscillator. The second is the effect of poor process on crystal oscillator.
From the perspective of the application, it generally refers to the deviation amount of actual output frequency that is caused by the temperature ranges.
This frequency offset is related to the operating temperature range, load capacitance, external capacitance and drive level of the passive crystal oscillator.
For active crystal oscillator, the instability of input voltage will also affect the accuracy of frequency output.
PCB design will also affect the frequency stability oscillator, such as too long circuit, electromagnetic interference, too much stray capacitance,
poor chip or false soldering, poor soldering, unreasonable wiring, software problems, etc.
From the perspective of quality, in the process of use and storage, crystal oscillator will appear aging phenomenon with the change of time,
such as improper use of raw materials, poor surface processing of quartz wafer, surface pollution, poor adhesion of evaporated silver film, etc.,
which will affect the frequency stability oscillator.
Generally speaking, we need to analyze the problems in the specific situation to solve the problems more efficiently.