A 240-Mbps, 1-W CMOS EPRML read-channel LSI chip using an interleaved subranging pipeline A/D converter

A 3.3-V, 1-W, 240-Mbps extended-partial-response maximum-likelihood read/write-channel large-scale-integration chip for hard disk drives has been developed. Power consumption of 1 W was achieved by using a 3.3-V power supply, a 0.4-/spl mu/m CMOS process, and a 3.3-V CMOS analog circuit design. Our approach to achieving a high transfer rate of 240 Mbps was to develop an interleaved subranging pipeline lookahead analog/digital (A/D) converter architecture. The power consumption of this A/D converter is 200 mW at 255 MHz. The read-mode channel path combines an acquisition-mode analog phase-locked loop (PLL) and a tracking-mode precision digital PLL, enabling the use of a long-latency pipeline A/D converter in the digital PLL. Consequently, a bit error rate of 10**(-9) at a signal-to-noise ratio of 24.5 dB has been achieved.