1-5hit |
The operating speed scalability is demonstrated by using the forward body biasing method for a 1-V 0.18-µm CMOS true single-phase clocking (TSPC) dual-modulus prescaler. With the forward body bias voltage varying between 0 and 0.4 V, the maximum operating speed changes by about 40–50% and the maximum input sensitivity frequency changes by about 400%. This speed scalability is achieved with less than 0.5-dB phase noise degradation. This demonstration indicates that the forward body biasing method is instrumental to build a cost-saving power-efficient 1-V 0.18-µm CMOS radio for low-power WBAN and WSN applications.
Toshimasa MATSUOKA Jun WANG Takao KIHARA Hyunju HAM Kenji TANIGUCHI
This paper introduces several techniques for achieving RF and analog CMOS circuits for wireless communication systems under ultra-low-voltage supply, such as 0.5 V. Forward body biasing and inverter-based circuit techniques were applied in the design of a feedforward Δ-ΣA/D modulator operating with a 0.5 V supply. Transformer utilization is also presented as an inductor area reduction technique. In addition, application of stochastic resonance to A/D conversion is discussed as a future technology.
Jun WANG Tuck-Yang LEE Dong-Gyou KIM Toshimasa MATSUOKA Kenji TANIGUCHI
This letter presents a 0.5 V low-voltage op-amp in a standard 0.18 µm CMOS process for switched-capacitor circuits. Unlike other two-stage 0.5 V op-amp architectures, this op-amp consists of CMOS inverters that utilize floating voltage sources and forward body bias for obtaining high-speed operation. And two improved common-mode rejection circuits are well combined to achieve low power and chip area reduction. Simulation results indicate that the op-amp has an open-loop gain of 62 dB, and a high unity gain bandwidth of 56 MHz. The power consumption is only 350 µW.
Yoshihide KOMATSU Koichiro ISHIBASHI Makoto NAGATA
This paper describes a method of reducing substrate noise and random variability utilizing a self-adjusted forward body bias (SA-FBB) circuit. To achieve this, we designed a test chip (130 nm CMOS 3-well) that contained an on-chip oscilloscope for detecting dynamic noise from various frequency noise sources, and another test chip (90 nm CMOS 2-well) that contained 10-M transistors for measuring random variability tendencies. Under SA-FBB conditions, it reduced noise by 35.3-69.8% and reduced random variability σ (Ids) by 23.2-57.9%.
Yoshihide KOMATSU Yukio ARIMA Koichiro ISHIBASHI
This paper describes a soft error hardened latch (SEH-Latch) scheme that has an error correction function in the fine process. The storage node of the latch is separated into three electrodes and a soft error on one node is collected by the other two nodes despite the large amount and long-lasting influx of radiation-induced charges. To achieve this, we designed two types of SEH-Latch circuits and a standard latch circuit using 130-nm 2-well, 3-well, and also 90-nm 2-well CMOS processes. The proposed circuit demonstrated immunity that was two orders higher through an irradiation test using alpha-particles, and immunity that was one order higher through neutron irradiation. We also demonstrated forward body bias control, which improves alpha-ray immunity by 26% for a standard latch and achieves 44 times improvement in the proposed latch.