What are the differences between active and passive crystal oscillators?

In the digital and intelligent transformation of modern society, crystal oscillators serve as the key to synchronizing electronic devices, primarily generating stable frequency signals. Traditionally, crystal oscillators are categorized into active and passive types, which differ significantly in functionality, applications, and characteristics. To help readers better distinguish between them, this article provides a detailed comparison of active and passive crystal oscillators.

1. Basic definition of active crystal oscillator and passive crystal oscillator.

An active crystal oscillator, as the name implies, is a crystal oscillator with an integrated power supply. It generates and provides the required electrical energy through its internal circuitry, eliminating the need for external power. The primary advantages of active crystal oscillators are their compact size and low power consumption. However, their drawbacks include the requirement for precise circuit matching to function properly and relatively high cost.

A passive crystal oscillator, also known as a crystal without built-in power supply, operates entirely through external power. Its key advantages include simple setup—just connect it with suitable capacitors and resistors—but it has drawbacks: requiring precise circuit matching for proper functioning, relatively large size, and higher power consumption.

2. The main difference between active crystal oscillator and passive crystal oscillator.

1. Power supply: Active crystals have built-in power, while passive crystals require external power.

2. Size and power consumption: Passive crystals require external power, resulting in larger dimensions and higher power consumption compared to active crystals.

3. Complexity of usage: Active crystal oscillators are relatively simple to use, requiring only the connection of appropriate capacitors and resistors. In contrast, passive crystal oscillators demand more complex matching circuits, otherwise they may fail to function properly.

4. Price: Passive crystals typically cost more than active crystals due to their need for additional power supply and complex matching circuits.

5. Performance: Generally, active crystal oscillators outperform passive ones in terms of accuracy, stability, and other performance metrics.

III. Summary

In summary, active and passive crystal oscillators each have their own advantages and disadvantages, and the choice of oscillator type depends on specific application requirements. For critical fields such as network communication, radar detection, precision measurement, and industrial control, Saisi offers a range of mid-to-high-end active crystal oscillators with ultra-low noise and ultra-high stability, available in standard or customized configurations. The product lineup includes both passive and active oscillators, featuring a maximum background phase noise of-188dBc/Hz, short-term stability of 1.08E-13/s, and temperature stability of-40 to 85°C with ≤1E-11.