VCXO and VCSO

VCXOs are key to building phase locked loops (PLLs) from scratch. These products are used for a variety of applications such as 5G RRHs, high speed DAC/ADC/SERDES, military radios, optical networks and microwave backhaul/ point to point. 

An XO is the simplest of all oscillators. Although the stability performance is usually the lowest of all the oscillator families, it excels in terms of floor phase noise and RMS jitter performance. A VCXO allows the user to manually adjust a control voltage to compensate for instabilities in the output frequency. It is used to bring the oscillator back to frequency after being impacted by instabilities (e.g. long term stability). Because of the additional components, a VCXO’s floor phase noise and RMS jitter are slightly impacted.

Sinewave and CMOS outputs provide the best phase noise out of all these types. LVPECL and LVDS provide very good signal security to minimise external interferences and therefore are more secure output types. The last difference is that CMOS is unable to operate at higher frequencies (greater than 200MHz), whereas sinewave, LVPECL and LVDS can operate in the GHz frequency ranges.