Complete explanation of professional terms in the crystal oscillator industry!

In the crystal oscillator industry, understanding the terminology related to crystal oscillators is crucial for selecting and applying them correctly. This article will delve into some common crystal oscillator related terms to facilitate a better understanding of crystal oscillator technology.

1. Piezoelectric effect: refers to the phenomenon in which a crystalline material generates an equal amount of charge on its surface when subjected to mechanical stress or pressure. This phenomenon is called piezoelectric effect.

2. Nominal frequency: refers to the frequency value output by an oscillating circuit under normal matching, expressed in MHz or KHz. The higher the frequency of the crystal oscillator, the faster the system operates.

3. Frequency range: refers to the minimum and maximum frequencies at which the crystal oscillator can operate stably. High performance devices may require higher crystal oscillator frequencies and operating frequencies to ensure their processing power and response speed, while low performance devices can choose lower frequencies to reduce power consumption and costs. ‌‌

4. Output mode (also known as "output waveform"): refers to the signal form output by the crystal oscillator (such as CMOS, LVPECL, LVDS, HCSL, etc.). ‌

5. Vibration modes: Quartz chips exhibit various vibration modes due to the electric field effect of different quartz cutting angles and electrode shapes. The frequently generated vibration modes can be divided into bending mode, stretching mode, surface shear mode, and thickness shear vibration mode.

6. Fundamental frequency: refers to the lowest order vibration frequency of the crystal oscillator in the vibration mode.

7. Pantone: refers to the mechanical harmonic of crystal vibration. The ratio of overtone frequency to fundamental frequency is close to an integer multiple but not an integer multiple, which is its main difference from electrical harmonics. There are 3 overtones, 5 overtones, 7 overtones, 9 overtones, etc. in overtone vibration.

8. Frequency deviation (also known as "crystal oscillator accuracy"): refers to the deviation between the output frequency of the crystal oscillator and the nominal frequency, expressed in parts per million (ppm). The smaller the ppm value, the higher the crystal oscillator accuracy, that is, the higher the clock accuracy of the system, thus ensuring the stable operation of the system.

9. Load capacitance: refers to the external capacitance required by the crystal oscillator, used to adjust the resonance frequency and stability of the crystal oscillator. Choosing the appropriate load capacitor can optimize the performance of the crystal oscillator. Once any external capacitor is connected in series with a quartz crystal component, it becomes a determining factor in its resonant frequency. When the load capacitance changes, the frequency will also change accordingly. Therefore, when used in circuits, the standard load capacitance is often used to fine tune the frequency to the desired value.

10. Frequency stability: refers to the degree of frequency variation of the output signal of the crystal oscillator. High frequency stability indicates that the frequency variation of the output signal is very small, and the crystal oscillator has good time measurement ability. ‌‌

11. Temperature stability: refers to the degree to which the frequency of the output signal of a crystal oscillator changes with temperature. The higher the temperature stability, the more stable the frequency output of the crystal oscillator can be maintained at different temperatures, indicating higher system stability and suitability for applications with a wide temperature range. ‌

12. Drive power: refers to the maximum output power that the crystal oscillator output signal can provide. A higher drive power means that the crystal oscillator can drive more load circuits, making it suitable for applications that require driving complex circuits. ‌‌

13. Drive level: refers to the minimum power supply voltage required for the crystal oscillator to operate. By using an oscilloscope and power supply to test the driving level, it is possible to observe whether the waveform is stable, thereby ensuring the reliable operation of the crystal oscillator.

14. Phase noise: refers to the instantaneous fluctuation or amplitude of the output signal phase of a crystal oscillator. A lower phase noise indicates that the crystal oscillator has better frequency stability and less clock jitter. Phase noise mainly affects the shape, amplitude, and frequency of signals. ‌

15. Phase jitter: refers to the uncertainty of digital signals in time, also known as time jitter or time offset. It is usually caused by interference or instability in the rising or falling process of digital signals.

16. Start up time: refers to the time required for the crystal oscillator to reach a stable working state from a non working state, and the start up time depends on the internal circuit and characteristics of the crystal oscillator. ‌

17. Working temperature range: refers to the ambient temperature range within which the crystal oscillator can operate normally, usually determined by the temperature limitations of the crystal resonator and packaging materials. In low-temperature environments, due to the high impedance of crystal resonators, the output power of the driving circuit can be too low, which can affect the stability and distortion of the output waveform; In high-temperature environments, water vapor and impurities in crystal resonators will evaporate, causing a decrease in resonant frequency and affecting the accuracy and stability of the crystal oscillator. ‌

18. Storage temperature range: refers to the temperature range in which the crystal oscillator can be safely stored when not in use. This range refers to the temperature range in which the crystal oscillator can be stored for a long time without damage or performance degradation. If the temperature exceeds this range, it may cause the internal materials of the crystal oscillator to become brittle, freeze, expand, or fail, thereby affecting the performance and reliability of the crystal oscillator. ‌

19. Resonant resistance: refers to the resistance value of a crystal oscillator at the resonant frequency. It is composed of the resistive part of the internal circuit components of the crystal oscillator and the load resistance connected to the external circuit. Resonant resistance plays an important role in regulating the damping effect of oscillating circuits, affecting the performance and stability of crystal oscillators.

20. Insulation resistance: refers to the resistance between the insulation leads (pins or pads) of a crystal oscillator or between the leads and the crystal oscillator casing. The testing of crystal oscillator insulation resistance (IR) is a quantitative test that reflects the electrical insulation efficiency of the crystal oscillator, that is, the ability of the crystal oscillator material to resist leakage current under DC bias gradient. The higher the insulation resistance value requirement, the better, and the more reliable the non conductivity between them. In other words, the higher the insulation resistance of a crystal oscillator, the stronger its ability to resist leakage current, thereby improving operational reliability and stability.

21. Negative impedance: refers to the impedance characteristic value of the oscillating circuit at the oscillation frequency when viewed from the two terminals of the quartz crystal resonator towards the oscillating circuit. Negative impedance is not a product parameter of quartz oscillators, but an important characteristic parameter of oscillation circuits. To improve the starting conditions in oscillating circuits, it is necessary to increase the negative impedance in the oscillating circuit, and without sufficient negative impedance deviation in the circuit, it is difficult to start oscillating. The value of negative impedance in an oscillating circuit should reach 5-10 times the resonant impedance.

22. Power consumption: refers to the electrical energy consumed by the crystal oscillator during operation. The lower the power consumption of the crystal oscillator, the lower the energy consumption of the system, thereby extending the battery life of the system.

23. Duty cycle: refers to the ratio of the duration of a high level in a periodic signal to the entire signal cycle time, usually expressed in percentage form. Ideally, a 50% duty cycle means that the time for high and low levels is equal, and this ratio is crucial for ensuring signal stability and accuracy.

24. Aging rate: refers to the speed at which the frequency of a crystal oscillator gradually changes over time of use. As the usage time of the crystal oscillator increases, the frequency of the crystal oscillator may undergo slight drift or change due to the gradual physical and chemical changes in the internal materials, as well as the influence of the external environment. The aging rate describes the rate at which this frequency changes. A lower aging rate indicates slow frequency changes in the crystal oscillator, while a higher aging rate indicates faster frequency changes.

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