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Yuuki ARAGA Nao UEDA Yasumasa TAKAGI Makoto NAGATA
A probing front end circuit (PFE) senses and digitizes voltage noises at in-circuit locations on such as power supply wiring and substrate taps in a chip, with the simplest circuit construction only with a source follower or a unity gain buffer, followed by a latch comparator. The PFE with 2.5V I/O transistors in a 65nm CMOS technology node demonstrates 9.0 ENOB and 60.7dB SFDR in equivalent sampling at 1.0Gs/s, for a sinusoidal waveform of 10MHz with 200mV peak-to-peak amplitude. Behavioral modeling of an entire waveform acquisition system using PFEs includes the statistical variations of reference voltage and sampling timing. The simulation quantitatively explains the measured dynamic properties of on-chip noise monitoring, such as the AC response in SNDR and digitizing throughputs, with the clear dependency on the frequency and amplitude of input waveforms.
Woojin JIN Seongtae YOON Yungseon EO Jungsun KIM
IC interconnect transmission line effects due to the characteristics of a silicon substrate and current return path impedances are physically investigated and experimentally characterized. With the investigation, a novel transmission line model is developed, taking these effects into account. Then an accurate signal delay on the IC interconnect lines is analyzed by using the transmission line model. The transmission line effects of the metal-insulator-semiconductor IC interconnect structure are experimentally verified with s-parameter-based wafer level signal-transient characterizations for various test patterns. They are designed and fabricated with a 0.35 µm CMOS process technology. Throughout this work, it is demonstrated that the conventional ideal RC- or RLC-model of the IC interconnects without considering these detailed physical phenomena is not accurate enough to verify the pico-second level timing of high-performance VLSI circuits.
In this paper, we discuss on accuracy of power dissipation medels for CMOS VLSI circuits. Some researchers have proposed several efficient power estimation methods for CMOS circuits. However, we do not know how accurate they are because we have not established a method to compare the estimated results of power consumption with power consumption of actual VLSI chips. To evaluate the accuracy of several kinds of power dissipation models in chip-level, block-level and gate-lebel etc., we have been (i) Measuring power consumtion of actual microprocessors, (ii) Estimating power consumption with several kinds of power dissipation models, and (iii) Comparing (i) with (ii). The experimental results show as follows: (1) Power estimation at gate level is accurate enough. (2) Estimating power of a clock tree independently makes estimation more accurate. (3) Area of each functional block is a good approximation of load capacitance of the block.