A Low-Power Multi-Phase Oscillator with Transfer Gate Phase Coupler Enabling Even-Numbered Phase Output

Toshihiro KONISHI  Hyeokjong LEE  Shintaro IZUMI  Takashi TAKEUCHI  Masahiko YOSHIMOTO  Hiroshi KAWAGUCHI  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E94-A   No.12   pp.2701-2708
Publication Date: 2011/12/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E94.A.2701
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
Category: Circuit Design
Keyword: 
multi-phase oscillator,  transfer gate phase coupler,  even-numbered phases,  low-power,  process scalable,  

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Summary: 
We propose a transfer gate phase coupler for a low-power multi-phase oscillator (MPOSC). The phase coupler is an nMOS transfer gate, which does not waste charge to the ground and thus achieves low power. The proposed MPOSC can set the number of outputs to an arbitrary number. The test circuit in a 180-nm process and a 65-nm process exhibits 20 phases, including 90 different angles. The designs in a 180-nm CMOS process and a 65-nm CMOS process were fabricated to confirm its process scalability; in the respective designs, we observed 36.6% and 38.3% improvements in a power-delay products, compared with the conventional MPOSCs using inverters and nMOS latches. In a 65-nm process, the measured DNL and 3σ period jitter are, respectively, less than 1.22 and 5.82 ps. The power is 284 µW at 1.85 GHz.