A Fractional-N PLL for SONET-Quality Clock-Syntlhesis Applicationis

A frequency-synthesis IC, targeted toward replacing high frequency XOs and VCXOs, is proposed. It is based on a fixed-frequency XO and a fractional-N PLL. A linearized phase detector, phase-error cancellation, and an integrated shielded LC-VCO are used. The measured jitter is 0.3ps rms in the OC-192 band. The chip draws 70mA excluding the output driver.