This paper presents an extremely low-power CMOS/SIMOX divide-by-128/129 dual-modulus prescaler. While operating at up to 1 GHz and dissipating merely 0.9 mW at a supply voltage of 1 V, it is capable of 2-GHz performance with dissipation of 7.2 mW at 2 V. This superior performance is primarily achieved by using an advanced ultrathin-film CMOS/SIMOX process technology combined with a new circuit configuration that uses a divide-by-2/3 synchronous counter. Using these same technologies, a single-chip CMOS PLL LSI that uses the developed prescaler is also fabricated. This CMOS PLL LSI can operate at up to 2 GHz while dissipating only 8.4 mW at a supply voltage of 2 V. Even at a lower supply voltage of 1.2 V, 1-GHz operation can be obtained with a corresponding power consumption of merely 1.4 mW. These results indicate that the high-speed and very-low-power features of CMOS/SIMOX technology could have an important impact on the development of future personal communication systems.

We designed and fabricated a prototype 0.4-µm-gate CMOS/SIMOX PLL LSI in order to verify the potential usefulness of ultrathin-film SIMOX technology for creating an extremely low-power LSI containing high-speed circuits operating at frequencies of at least 1 GHz and at low supply voltages. This PLL LSI contains both high-frequency components such a prescaler and low-frequency components such as a shift register, phase frequency comparator, and fixed divider. One application of the LSI could be for synthesizing communication band frequencies in the front-end of a battery-operated wireless handy terminal for personal communications. At a supply voltage of 2 V, this LSI operates at up to 2 GHz while dissipating only 8.4 mW. Even at only 1.2 V, 1 GHz-operation can be obtained with a power consumption of merely 1.4 mW. To explain this low-power feature, we extensively measured the electrical characteristics of individual CMOS/SIMOX basic circuits as well as transistors. Test results showed that the high performance of the LSI is mainly due to the advanced nature of the CMOS/SIMOX devices with low parasitic capacitances around source/drain regions and to the new circuit design techniques used in the dual-modulus prescalar.

A computer-aided low-power design methodology for very high-speed Si bipolar standard cell LSI is described. In order to obtain Gbit/s-speed operation, it features a pair of differential clock channels inside cells and a highly accurate static timing analysis for back annotation. A newly developed CAD-based power optimization scheme minimizes cell currents while maintaining circuit speed. A 5.6 k gate SDH signal-processing LSI operating at 1.6 Gbit/s with only 3.9 W power consumption demonstrates the effectiveness of this design technology.