High frequency clock rate is a key issue in today's VLSI. To improve performance on-chip, clock multipliers are used. But it is a difficult task to design such circuits while maintaining low cost. This paper presents a circuit fabricated to test a new method of clock frequency multiplication. This new approach uses a digital CMOS process in order to implement a fully integrated digital delay locked loop. This multiplier does not require external components. Moreover, as it is primarily intended for ASIC design, it is generated by a parameterized generator written in C which relies on a portable digital standard cell library for automatic place and route. The design based on the delay locked loop allows the clock waveform to reach its operating point faster than conventional methods. Special techniques enable high multiplication factors (between 4 and 20) without compromising the timing accuracy. With a clock multiplier of 20, in 1 pm CMOS process and a 5 V supply voltage, a 170 MHz clock signal has been obtained from a 8.5 MHz external clock with a measured jitter lower than 300 ps.
This paper presents the performance of the static timing analyzer TAS for deep submicronic CMOS technologies. The methodology used by TAS is given with special emphasis on its Short Channel MOS model. Results are given to show the accuracy of the static timing analyzer TAS for various CMOS circuits (including pass transistor and precharge logic) as well as for various CMOS processes ranging from 1.2J.t to 0.35J.t. The Short Channel MOS model of TAS appears to be relevant to the analysis of deep submicronic processes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.