Ramesh Harjani

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We describe a hierarchical structure for a knowledge-based analog circuit synthesis tool. Analog circuit topologies are represented as a hierarchy of abstract functional blocks each with associated design knowledge. We also describe mechanisms to select from among alternate design styles, and to translate performance specifications from one level in the(More)
This paper presents a technique to efficiently supply power over a wide power range using a fully integrated on-chip converter for dynamic voltage scaling (DVS) based applications. All components, including filter elements, are integrated onchip. To achieve high efficiency the converter adaptively switches between different modes of operation by detecting(More)
This paper presents a framework for modeling the phase noise in complementary metal–oxide–semiconductor (CMOS) ring oscillators. The analysis considers both linear and nonlinear operations, and it includes both device noise and digital switching noise coupled through the power supply and substrate. In this paper, we show that fast rail-to-rail switching is(More)
Ultra-wideband communications systems offer unique challenges and opportunities for RF circuit design. Proper understanding of the trade-offs that system specifications impose upon the circuit designer is essential in optimizing a system for UWB. The defining attribute of UWB is the wide fractional bandwidth of the signal. This wide bandwidth can be(More)
We describe an all CMOS variable gain ampliier (VGA) suitable for use in disk drive read channels. The VGA maintains a 3dB bandwidth greater than 85 MHz throughout its gain range. This ensures good phase linearity for data transfer rates of up to 50Mb/s. The VGA provides a 25dB gain variation along an ideal exponential gain to control voltage curve and 30dB(More)