Introduce crystals and crystal oscillators and compare the process of quartz crystal oscillator with MEMS silicon crystal oscillator

This article briefly introduces the conceptual aspects of crystals and crystal oscillators, and briefly describes the process of quartz crystal oscillators and MEMS silicon crystal oscillators, as well as parameter comparisons.

First, the difference between crystal and crystal.

The name of the crystal and the crystal oscillator is quite chaotic in China. Many people will collectively call the crystal and the crystal oscillator a crystal. Generally speaking, crystal refers to passive crystal oscillator, English name: Crystal. A series capacitor is required to start the oscillation. The crystal oscillator is also called an active crystal oscillator. The English name is Oscillctor. There is no need for a series capacitor, and there is a clock output when powered up.
Introduce crystals and crystal oscillators and compare the process of quartz crystal oscillator with MEMS silicon crystal oscillator

Second, the production process of quartz crystal.

The quartz crystal oscillator is subjected to dozens of processes such as cutting, grinding, silver plating, dispensing, and nitrogen filling. There are risks associated with the following issues:

1. Fragile: Because of the precision required, quartz wafers need to be very thin. Therefore, it is very easy to break during transportation.

2, the quality is inconsistent: In addition to the fragile situation, too high temperature (such as: welding) will easily lead to loosening of the glue, resulting in bad products.

3, air leakage: Because the accuracy of quartz crystal oscillator has a direct relationship with silver plating, if the metal shell is not well sealed, it is easy to leak and be oxidized, resulting in a relatively large frequency deviation.

Therefore, the DPPM of the quartz crystal is between 200-300. (DPPM is the abbreviation of defective parts per million. It refers to the defect rate of parts per million. Production quality terminology)

Third, the production process of MEMS silicon crystal.

MEMS silicon crystals use a standard semiconductor process, and both Die and package are fully automated processes. Essentially solve all the risks of quartz crystal:

1, high shock resistance: 50000G shock resistance, stone fell, force stepping, pliers folder is no problem.

2, high quality consistency: DPPM is 0.15, which means that there are 0.15 defects in one million pieces.

3, high precision: ordinary chip has a temperature compensation circuit inside, full temperature accuracy guarantee.

The Sitime MEMS silicon crystal is 100% compatible with quartz crystals and can be directly replaced without any circuit changes.


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