Timing and data recovery circuit for high-speed optical storage drives

A new timing recovery circuit for high-speed optical storage drives is presented. The core of the timing recovery circuit is a mixed-signal-controlled oscillator (MSCO) which is controlled simultaneously by a digital signal and an analogue signal. With digital control, the MSCO can operate in a broad frequency range, with very high switching speed and flexibility. Within a small frequency step defined by a particular digital control word, an analogue control signal can then fine-tune the MSCO through a feedback loop. In addition, to accommodate the data-transition characteristics in the CD-ROM or DVD-ROM data, a new phase detector is proposed. The proposed IC also includes a frame synchronisation block and an eight-to-fourteen demodulation circuit for CD-ROM data recovery. The chip was fabricated in a 0.6-mum n-well SPTM CMOS process. The timing recovery circuit achieves an operating frequency range of 70-180 MHz and its acquisition time is much less than 1 mus while consuming only 85 mW from a 5 V power supply.