In electronic system timing design, both programmable oscillators (POOs) and active crystal oscillators are key components providing stable clock signals. The main differences between active and programmable crystal oscillators are described below:
Definition and Function:
Active Crystal Oscillator：A complete module integrating a quartz crystal and oscillation circuit. It directly outputs a square wave signal at a fixed frequency after power-on, requiring no external circuitry.
Programmable Crystal Oscillator：A crystal oscillator whose output frequency can be programmed. Users can adjust parameters such as frequency according to their needs, offering greater flexibility.
Frequency Adjustability:
Active Crystal Oscillator：The output frequency is fixed and cannot be changed.
Programmable Crystal Oscillator：Supports frequency programming, allowing adjustment of the output frequency within a certain range.
Internal Structure:
Active Crystal Oscillator：Relatively simple in structure, mainly composed of a quartz crystal and oscillation circuit.
Programmable Crystal Oscillator:** Complex in structure, containing a crystal oscillator chip, microcontroller chip, PLL chip, etc.
Performance Parameters:
Active Crystal Oscillator：Internally contains only CMOS circuitry, resulting in low current consumption and high phase noise jitter performance.
Programmable crystal oscillators: In addition to CMOS circuitry, they also contain PLL circuitry. The programming process activates the PLL circuitry, consuming more current than ordinary active crystal oscillators.
Production and Delivery:
Active crystal oscillators: Require production according to the crystal oscillator manufacturing schedule, with a lead time of approximately 4 weeks.
Programmable crystal oscillators: Use pre-made crystal oscillators for direct programming, allowing for rapid delivery in 1-2 days.
Application Scenarios:
Active crystal oscillators: Suitable for general electronic devices requiring stable clock signals, such as communication equipment, computers, and industrial control systems.
Programmable crystal oscillators: Suitable for high-end applications requiring flexible frequency configuration, such as communication equipment, medical instruments, and industrial automation control systems.
