Ryoichi Tachibana
Toshiba
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Publication
Featured researches published by Ryoichi Tachibana.
european solid-state circuits conference | 2007
Hiroaki Hoshino; Ryoichi Tachibana; Toshiya Mitomo; Naoko Ono; Yoshiaki Yoshihara; Ryuichi Fujimoto
A 60-GHz phase-locked loop (PLL) with inductor-less prescaler is fabricated in a 90-nm CMOS process. The inductor-less prescaler has a smaller chip area than previously reported ones. The PLL operates from 61 to 63 GHz and consumes 78 mW from a 1.2 V supply. The phase noise at 100 kHz and 1 MHz offset from carrier are -72 and -80 dBc/Hz, respectively. The prescaler occupies 80 x 40 mum2. The active area of the PLL is 0.6 x 0.6 mm2.
symposium on vlsi circuits | 2007
Toshiya Mitomo; Ryuichi Fujimoto; Naoko Ono; Ryoichi Tachibana; Hiroaki Hoshino; Yoshiaki Yoshihara; Yukako Tsutsumi; Ichiro Seto
A 60-GHz receiver (RX) chip fabricated in 90 nm CMOS process is reported. The RX chip consists of an LNA, a downconversion mixer and a phase-locked loop synthesizer. The RX chip is capable of generating LO signal from phase-locked synthesizer. Measured power gain and NF of 22 dB and 8.4 dB were obtained at 61.5 GHz. These results indicate the possibility of realization of CMOS single-chip 60-GHz transceiver.
international solid-state circuits conference | 2014
Shigehito Saigusa; Toshiya Mitomo; Hidenori Okuni; Masahiro Hosoya; Akihide Sai; Shusuke Kawai; Tong Wang; Masanori Furuta; Kei Shiraishi; Koichiro Ban; Seiichiro Horikawa; Tomoya Tandai; Ryoko Matsuo; Takeshi Tomizawa; Hiroaki Hoshino; Junya Matsuno; Yukako Tsutsumi; Ryoichi Tachibana; Osamu Watanabe; Tetsuro Itakura
A fully-integrated single-chip CMOS transceiver with MAC and PHY for 60GHz proximity wireless communication is presented. A 60GHz wireless communication single-chip transceiver has not yet been reported due to large power consumption issues. However, by limiting the application to high-throughput proximity transmission, thermal issues arising in a single-chip have been overcome. A 2GHz broadband OFDM single-chip transceiver suffers from SNR degradation due to the reference clock (REFCLK) and baseband clock (BBCLK) spurs in RF/analog circuits. Low frequency spurs in the clock generator (CLKPLL) due to the mixing of the ADC/DAC sampling clock (SCLK) and other clocks such as REFCLK and BBCLK have been eliminated by careful frequency planning of those clocks. In addition to that, spur suppression in digital baseband and noise-tolerant RF/analog circuit designs are employed. The spurs have been successfully suppressed to less than -35dBc. The chip achieves a PHY data-rate of 2.35Gb/s and MAC throughput of 2.0Gb/s at a distance of 4cm. Power consumption is scalable to the throughput by the introduction of fast Sleep and Awake modes. The average power consumption at a throughput of 0.2Gb/s is reduced to 36% of that at 2.0Gb/s.
radio frequency integrated circuits symposium | 2007
Ryoichi Tachibana; Shouhei Kousai; Takayuki Kato; Hiroyuki Kobayashi; Rui Ito; Asuka Maki; Daisuke Miyashita; Yuta Araki; Toru Hashimoto; Hiroaki Hoshino; Takahiro Sekiguchi; Mitsuyuki Ashida; Ichiro Seto; Mototsugu Hamada; Ryuichi Fujimoto; Hiroshi Yoshida; Shoji Otaka
A 5 GHz MIMO direct-conversion transceiver composed of 2 transmitters (TXs) and 3 receivers (RXs) is fabricated with 0.13 mum CMOS technology. Die size is 4.56 mm times 7.7 mm. For driving 10 GHz LO signal lines of 5 mm length for both TXs and RXs, inductor-less low-power LO repeaters are equipped in individual LO paths. A linearized RF variable gain amplifier is proposed for low power operation. Isolation of over 40 dB is obtained by equipping separate GNDs on both the MIMO IC and the circuit board. This results in negligible degradation of EVM. TX EVM of over -31 dB is obtained at -8.6 dBm for 2 TX mode when external LO of 10 GHz is applied. The 3 RXs and 2 TXs with LO paths dissipate 703 mW and 412 mW from 1.5 V, respectively.
international solid-state circuits conference | 2012
Toshiya Mitomo; Yukako Tsutsumi; Hiroaki Hoshino; Masahiro Hosoya; Tong Wang; Yuta Tsubouchi; Ryoichi Tachibana; Akihide Sai; Yuka Kobayashi; Daisuke Kurose; Tomohiko Ito; Koichiro Ban; Tomoya Tandai; Takeshi Tomizawa
Archive | 2009
Hiroki Sakurai; Osamu Watanabe; Shoji Otaka; Ryoichi Tachibana
IEICE Transactions on Electronics | 2009
Hiroaki Hoshino; Ryoichi Tachibana; Toshiya Mitomo; Naoko Ono; Yoshiaki Yoshihara; Ryuichi Fujimoto
Archive | 2007
Hiroaki Hoshino; Shoji Ootaka; Ryoichi Tachibana
Archive | 2008
Ryoichi Tachibana; Shoji Otaka; Osamu Watanabe; Hiroaki Hoshino
Archive | 2007
Hiroaki Hoshino; Shoji Otaka; Ryoichi Tachibana; Osamu Watanabe; 章二 大高; 洋昭 星野; 理 渡辺; 良一 立花