I2C-programmable crystal oscillators have ultra-low jitter in the 95fs range

December 14, 2017 // By Julien Happich
The Si54x Ultra Series of I2C-Programmable crystal oscillators (XOs) announced by Silicon Labs maximize jitter margin for clocking high-speed 28 Gbps and 56 Gbps transceivers used in 100/200/400G communications and data center applications.

With a typical jitter performance as low as 95 femtoseconds (fs), the Si544/Si549 Ultra Series are capable of generating any frequency from 200kHz to 1.5GHz with no frequency gaps and 4 parts-per-trillion (ppt) tuning resolution, enabling a single device to be used across a broad spectrum of applications.
The Si544/Si549 XOs support up to four preset, pin-selectable start-up frequencies. After power-up, the device operating frequency can easily be changed via an I2C interface. This configuration flexibility enables a single oscillator to replace multiple single, dual and quad-frequency XOs and multiplexer (mux) devices with a single oscillator. The device can be powered from a single 1.8, 2.5 or 3.3 V supply, eliminating the need for different XO part numbers for different supply voltages. The Si54x XO’s I2C interface supports update rates as high as 1 MHz (Fast-mode Plus), maximizing compatibility with a broad range of ASSPs, ASICs, SoCs and FPGAs. The chips come in 3.2x5mm and 5x7mm packages, providing superior frequency flexibility in the same footprint as a standard, fixed-frequency XO. The Si544/Si549 oscillators support all popular output formats including LVDS, LVPECL, HCSL, CML, CMOS and Dual CMOS.
Silicon Labs - www.silabs.com