Spread-Spectrum Clock Generator for Serial ATA with Multi-Bit ΣΔ Modulator-Controlled Fractional PLL

Masaru KOKUBO  Takashi KAWAMOTO  Takashi OSHIMA  Takayuki NOTO  Masato SUZUKI  Shigeyuki SUZUKI  Takashi HAYASAKA  Tomoaki TAKAHASHI  Jun KASAI  

IEICE TRANSACTIONS on Electronics   Vol.E89-C    No.11    pp.1682-1688
Publication Date: 2006/11/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e89-c.11.1682
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Circuits
PLL,  spread-spectrum,  jitter,  serial ATA,  

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We have developed a spread-spectrum Phase-Locked Loop (PLL) for serial Advanced Technology Attachment (ATA) applications. We investigated the relation between the output jitter of PLLs in serial ATA applications and ΣΔ modulators in PLLs. On the basis of this study, we developed a spread-spectrum PLL for serial ATA applications and achieved a combination of small jitter and large electromagnetic interference (EMI) peak power reduction. This was achieved using two key components: multi-bit ΣΔ-controlled PLL and voltage-controlled oscillation with cross-coupled load delay cells. Using a 0.15-µm complementary metal-oxide semiconductor process, we fabricated a complete serial ATA transceiver featuring a spread-spectrum clock generator (SSCG). We achieved a spread-spectrum PLL with 10-dB EMI reduction and 8.1 ps random jitter for use in serial ATA applications. All other measured results for SSCG performance were very good and showed that the spread-spectrum generator more than satisfies serial ATA specifications.