Silicon Labs has introduced a new family of crystal oscillators (XOs) that look to provide ultra-low jitter reference timing for 10G, 40G and 100G cloud computing and networking equipment. These new Si535 and Si536 XOs leverage Silicon Labs’ DSPLL technology to provide improved levels of performance, stability and flexibility for 10/40G data centre core/access switches, storage area networking equipment, security routers, enterprise switches/routers, and Carrier Ethernet switches and routers.
To support the growing demand for cloud computing-based services, data centre equipment is migrating to higher speed serial data transmission, often 10G or faster. In parallel, there is a significant trend to maximise energy efficiency by consolidating switching, storage and computing resources into fewer components. These trends have given rise to processors, Ethernet switch ICs and FPGAs with integrated high-speed serializer-deserializer (SerDes) technology that requires low-jitter timing references. Silicon Labs’ Si535/536 oscillators look to address this market providing the ultra-low jitter and ±20 ppm stability that is required by state-of-the-art cloud computing and networking infrastructure equipment.
The Si535/536 XOs are able to offer exceptional jitter performance of <200 femtoseconds (fs) RMS jitter (integrated from 10 kHz to 1 MHz) for common Ethernet and Fibre Channel reference frequencies. They also support LVDS and LVPECL output formats at 2.5 V and 3.3 V and offer both ±20 ppm and 31.5 ppm total stability, simplifying interfacing to a wide variety of processors, switches, PHYs and FPGAs. When combined with Silicon Labs’ Si533xx differential clock buffers, the Si535/536 XOs provide low-jitter clock generation and distribution for SoCs requiring multiple high-performance reference clocks.
The Si535/536 oscillators use Silicon Labs’ patented DSPLL technology to provide a low-jitter clock at high-speed differential frequencies. Unlike a traditional XO in which a different crystal is required for each output frequency, they use a common fixed-frequency crystal to provide exceptional stability and reliability and leverage the DSPLL IC to generate any output frequency. In addition, DSPLL clock synthesis provides superior supply noise rejection, simplifying the task of generating low-jitter clocks in noisy environments typically found in data center and networking systems.
Oscillators based on DSPLL technology can be supplied at any output frequency without cutting and tuning a unique 3rd overtone (OT) crystal or surface acoustic wave (SAW) device, as required by competing low-jitter XOs. Silicon Labs’ mixed-signal IC-based approach also enables simplified factory programming at time of shipment, eliminating long lead times associated with custom oscillators. Si535/536 XO samples ship in two weeks, the shortest lead time in the high-performance frequency control industry.