Overview: Ultra Series™ Crystal Oscillator Si549 Data Sheet Ultra Low Jitter I2C Programmable XO (95 fs), 0.2 to 1500 MHz The Si549 Ultra Series™ oscillator utilizes Skyworks Solutions’ advanced 4th generation DSPLL® technology to provide an ultra-low jitter, low phase noise clock at any output frequency. The device is user-programmed via simple I2C commands to provide any frequency from 0.2 to 1500 MHz with <1 ppb resolution and maintains exceptionally low jitter for both integer and fractional frequencies across its operating range. The Si549 offers excellent reliability and frequency stability as well as guaranteed aging performance. On-chip power supply filtering provides industry-leading power supply noise rejection, simplifying the task of generating low jitter clocks in noisy systems that use switched-mode power supplies. The Si549 has a dramatically simplified supply chain that enables Skyworks to ship custom frequency samples 1-2 weeks after receipt of order. Unlike a traditional XO, where a different crystal is required for each output frequency, the Si549 uses one simple crystal and a DSPLL IC-based approach to provide the desired output frequency. The Si549 is factory-configurable for a wide variety of user specifications, including startup frequency, I2C address, output format, and OE pin location/polarity. Specific configurations are factory-programmed at time of shipment, eliminating the long lead times associated with custom oscillators.
