VCXO PLL Jitter Attenuators

IDT voltage-controlled crystal oscillator (VCXO) jitter attenuator devices are synchronous jitter attenuation and frequency translation products featuring a VCXO-based PLL stage with either internal VCXO requiring only an external pull-able crystal, or with an external low frequency VCXO. This PLL stage is typically configured with low loop bandwidth to provide jitter attenuation. It can also accommodate numerous pre, feedback, and output divider combinations to allow for frequency translation. The output frequency from the VCXO PLL stage is then followed by a frequency multiplier.

Some products use IDT’s FemtoClock® or FemtoClock NG technology for frequency multiplication. FemtoClock NG devices use a fixed crystal and perform the frequency pulling digitally using DPLL technology. The FemtoClock versions provide the capability to generate output frequencies up to 800 MHz with typical random phase-noise jitter of 1 ps RMS, while the NG versions have a maximum output frequency of up to 1.3GHz and a typical random phase-noise jitter of less than 0.7 ps RMS. These devices can be used in many applications to replace expensive VCSO PLLs.

Applications for VCXO PLL + Jitter Attenuators include synchronous Ethernet, wireless infrastructure, SONET/SDH, telecom and video.