What is the difference between SPXO and XO ?
SPXOs, or Spread Spectrum Crystal Oscillators, are a type of crystal oscillator that provide superior anti-interference characteristics in high-speed communication applications. They differ from conventional crystal oscillators (XOs) in terms of their output signals, which include LVPECL, LVDS, and HCSL. LVPECL and LVDS have been used in major differential systems for a long time.
SPXOs use a two-line transmission to output a set of signals with the same amplitude but opposite phase. The receiving end judges the logical state based on the voltage difference of the signal. This type of output signal is ideal for high-speed communication, where anti-interference characteristics are crucial.
Conventional crystal oscillators typically have TTL and HCMOS outputs, which are single-line outputs that are convenient for wiring arrangements but have poor anti-interference abilities and are not suitable for high-speed information above 100MHz.
LVPECL (Low Voltage Positive Emitter-Coupled Logic) is a non-saturated digital logic circuit that operates using a 3.3V or 2.5V power supply. It is one of the fastest logic circuits available and can meet operating rates of up to 10 Gbps. PECL/LVPECL is more widely used than ECL because it can share a positive power supply with other circuits in the system.
LVDS (Low Voltage Differential Signaling) is another type of output signal used by SPXOs. It is a low-amplitude differential signaling technology that allows signals to be transmitted at hundreds of Mbps over differential PCB pairs or balanced cables. It has low amplitude and low current drive outputs for low noise and low power consumption.
LVDS line working principle
In general, SPXOs are better suited for high-speed communication applications above 100MHz, while XOs are more suitable for frequencies below 100MHz. Additionally, the price of SPXOs is typically higher than XOs due to their advanced features and superior anti-interference capabilities.
In summary, SPXOs are an ideal choice for high-speed communication applications that require reliable and accurate signals. Their advanced features and superior anti-interference capabilities make them a popular choice among engineers and designers.