A crystal oscillator is an electronic circuit that generates an electrical signal with a very precise frequency. To achieve this, it uses the mechanical resonance of a vibrating crystal made of piezoelectric material.
The first crystal oscillator was invented in the late 1920s by Walter Guyton Cady who was interested in submarine detection with ultrasonic waves. He suggested that a piezoelectric resonator could be used as a frequency reference, a coupling device between circuits, or a filter.
Crystal oscillators are the most common type of linear oscillators. They are most commonly made of quartz, which sets the frequency at which a specific oscillator works. These devices are used in microcontrollers and microprocessors for providing the clock signals and other industrial applications such as computers, radios, clocks, watches, TVs and more.
There are different types of crystal oscillator circuits such as the Colpitts Crystal Oscillator which normally uses a common collector amplifier, Pierce Crystal Oscillator which uses transistors and FETs, the Butler oscillator which is a crystal-controlled oscillator and the Tri-tet oscillator which is a crystal-controlled vacuum tube oscillator circuit. The Pierce oscillator configuration is commonly used because of cost, size, stability, and easy implementation. It includes a resistor, two capacitors, a single digital inverter, along with the quartz crystal.
When designing a crystal oscillator circuit you should think in terms of the crystal’s internal series resistance. The equivalent series resistance that the crystal is seeing must be equal to or less than the crystal’s internal series resistance to get the best frequency stability. You can also include extra elements to avoid oscillation from happening when power is applied.
Let’s take a look at the top 10 Crystal Oscillators on SnapEDA!
Note: This data is based on downloads of symbols & footprints on SnapEDA. Browse more crystal oscillators here.
Read more: The top 10 crystal oscillators from SnapEDA
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