A programmable clock generator, based on a phase-locked loop (PLL) circuit, has been developed with 0.5 µm CMOS triple-layer Al interconnection technology for use as an on-chip clock generator in a 300-MHz video signal processor. The PLL-based clock generator generates a clock signal whose frequency ranges from 50 to 350 MHz which is an integral multiple, from 2 to 16, of an external clock frequency. In order to achieve stable operation within this wide range, a voltage controlled oscillator (VCO) with selectable low VCO gain characteristics has been developed. Experimental results show that the clock generator generates a 297-MHz clock with a 27-MHz external clock, with jitter of 180 ps and power dissipation of 120 mW at 3.3-V power supply, and it can also oscillate up to 348 MHz with a 31.7-MHz external clock.

This paper describes novel techniques for analyzing power MOSFETs. Since the gate width of power MOSFETs is much larger than that of power MESFETs or HJFETs, an appropriate device design to suppress matching circuit losses is needed. These losses and the intrinsic device characteristics are analyzed employing the proposed techniques, which are based on large-signal simulations. Also, new formulas describing the dependence of saturated output power on gate width are derived to perform loss-minimized design. These techniques are applied to the design of power MOSFETs for GSM cellular telephones. As a result, an output power of 35.5 dBm with a power-added efficiency of 55% and a power gain of 10.5 dB at 900 MHz have been achieved.

This paper presents a new data cache design, cache-processor coupling, which tightly binds an on-chip data cache with a microprocessor. Parallel architectures and high-speed circuit techniques are developed for speeding address handling process associated with accessing the data cache. The address handling time has been reduced by 51% by these architectures and circuit techniques. On the other hand, newly proposed instructions increase data cache bandwidth by eight times. Excessive power consumption due to the wide-bandwidth data transfer is carefully avoided by newly developed circuit techniques, which reduce dissipation power per bit to 1/26. Simulation study of the proposed architecture and circuit techniques yields a 1.8 ns delay each for address handling, cache access, and register access for a 16 kilobyte direct mapped cache with a 0.4 µm CMOS design rule.

We have proposed area-reduction techniques for superscalar datapath architectures with 34 SIMD instructions and have developed an integer-media unit based on these techniques. The unit's design is both functionally asymmetrical and integer-SIMD unified, and the resulting savings in area are 27%-48% as compared to other, functionally equivalent mid-level microprocessor designs, with performance that is, at most, only 7.2% lower. Further, in 2-D IDCT processing, the unit outperforms embedded microprocessor designs without SIMD functions by 49%-118%. Specifically, effective area reduction of adders, shifters, and multiply-and-adders has been achieved by using the unified design. These area-effective techniques are useful for embedded microprocessors and scalable systems that employ highly parallel superscalar and on-chip parallel architectures. The integer-media unit has been implemented in an evaluation chip fabricated with 0.15-µm 5-metal CMOS technology.