Crystal Oscillators for Electronics

A crystal oscillator is an electronic circuit that uses the mechanical resonance of a quartz crystal, a piezoelectric component, to generate a stable frequency signal. The crystal oscillator circuit works by applying voltage to the crystal, causing it to vibrate at its resonant frequency; that oscillation is then sustained by a feedback circuit and amplifier. Quartz crystal oscillators are used in microprocessors, clocks, GPS receivers, and any electronic device requiring a precise clock signal.

The AT-cut crystal is the most common type of crystal, covering frequencies from 1 MHz to approximately 200 MHz with strong frequency stability across commercial and industrial temperature ranges. SC-cut crystals are stress-compensated, making them less sensitive to thermal and mechanical changes and the preferred choice for precision oscillator designs where phase noise and long-term frequency stability are critical.

The most widely used crystal frequencies fall in the megahertz range, typically between 20 MHz and 40 MHz, particularly for wireless communication. For real-time clock circuits and digital watches, 32.768 kHz is the standard. This frequency in kilohertz divides cleanly to one pulse per second using a simple flip-flop chain, making it ideal for low-power timekeeping.

Both quartz crystals and ceramic resonators vibrate when exposed to an AC signal, but quartz crystals deliver significantly higher frequency accuracy and stability. Ceramic resonators are lower cost but less precise, suited for applications where minor frequency drift is acceptable. Quartz crystals are the better choice for electronics where maintaining a stable frequency across temperature changes is essential.

Start with your circuit design requirements: operating frequency, cut type, load capacitance, frequency tolerance, and package type. A microprocessor crystal quartz clock, for example, typically pairs a crystal with two ceramic capacitors valued between 15 to 33pF in an oscillator circuit. For most applications, an AT-cut crystal in an SMD package is the right starting point. SC-cut and tighter tolerance options are warranted for precision communications, GPS, or long-lifecycle designs where the frequency stability of the crystal is critical.

Suntsu offers a full catalog of quartz crystal oscillators and frequency control crystals in SMD and through-hole packages, with standard and custom configurations available. Engineers needing higher stability can also explore our VCXO and temperature compensation oscillator options. Browse the collection above or contact our team directly for custom frequency, tolerance, or package specifications.