Choosing Between Quartz Crystals and Oscillators in Electronic Assemblies

One of the most critical decisions in developing an electronic assembly is selecting the appropriate frequency control product.  The two main options are quartz crystals and oscillators.  While both have their advantages, it's essential to consider several parameters to choose the right component for the application.

 

An oscillator is an electronic circuit that generates a periodic signal without requiring an external input. It can produce a precise frequency output, but it may not be as stable as a quartz crystal oscillator.

A quartz crystal is a highly stable piezoelectric resonator that vibrates at a specific frequency when an electric field is applied to it. It is used as a timing element in electronic circuits, and can provide a very accurate and stable frequency output.

Here are some factors to consider when choosing between an oscillator and a quartz crystal:

 

Frequency stability: The frequency stability of a component refers to how well it maintains a specific frequency output over time.  Quartz crystals are known for their high frequency stability and accuracy, making them suitable for applications that require precise timing and synchronization.  In contrast, oscillators may not be as stable as quartz crystals, but they can still provide a reliable frequency output for many applications.

 

Size and cost: The size and cost of a component are important considerations for many electronic designs, particularly those with limited space or budget.  Oscillators are typically smaller and less expensive than quartz crystals, making them a good choice for applications where space and cost are a concern.

 

Environmental factors: The environmental factors that a component will be subject to can greatly impact its performance and reliability.  Quartz crystals are known for their stability under varying environmental conditions, such as temperature, humidity, and vibration.  In contrast, oscillators may be sensitive to these factors and may require additional measures to ensure reliable operation.

 

Power consumption: The power consumption of a component is an important consideration for battery-powered devices or applications where power usage is a concern.  Quartz crystals consume less power than oscillators, making them a good choice for applications where power consumption needs to be minimized.  However, oscillators can still provide a reliable frequency output while consuming slightly more power than quartz crystals.

 

In situations where the developer wants to build their own electronic oscillator and tune all the relevant parameters, a quartz crystal is the better choice. However, this requires building and adapting the oscillator to ensure oscillation stability over the entire operating temperature range. Components such as capacitors must be carefully selected to achieve the quartz crystal's specific load capacity, or significant deviations from the specified nominal frequency may occur. Defining the specifications for the quartz crystal in advance is crucial to avoid frequency deviations.

Choosing between a quartz crystal and an oscillator depends on several factors, such as stability, space requirements, and development costs.  While quartz crystals require more effort for building and adaptation to achieve oscillation stability, they are less expensive than crystal oscillators and make an excellent choice for larger quantities.  On the other hand, crystal oscillators offer improved frequency stability, consume less power, and require less space on the board.  Ultimately, the decision of which component to choose depends on the specific needs of the application and its requirements.