Automation of the ic layout of continuous‐time transconductance‐capacitor filters

Abstract

SUMMARYTo exploit the increased circuit density available in current technologies for continuous-time (c-t) systems, it is proposed to extend the range of analogue design automation to the larger c-t subsystems, specifically filters, commonly found in communications, mass storage devices and other interfaces to real-world signals. The synthesis is based on LC ladder simulation using only transconductances and grounded capacitors (TGC). The method retains many of the characteristics of digital design automation and therefore allows a direct mapping of these techniques. The TGC approach is shown to require a minimum of component types which are ideally suited to integration in MOS, bipolar or GaAs technologies. A simple example for the automation of c-t filter designs as well as results of CMOS c-t filters are included to demonstrate the viability of this approach. Related and equally important areas addressed are tuning, compensation for parasitics and scaling.

Design and Design Automation of Continuous-Time Fully Integrated Transconductance-C Filters

“…As an example that appeared on several occasions in the literature in different technologies [5,13,14,27], consider the implementation of a third-order elliptic lowpass as a fully differential g m -C ladder. The LC prototype and the g m -C circuit are shown in Figs.…”

Generation of Transconductance Grounded Capacitor Filters from LC Ladder Prototypes Based on Multi-Terminal Gyrator Principles

“…In addition, gain is necessary for the realization of complex poles because the poles of passive GC-circuits are restricted to the negative real axis. Combining with conductances into transconductances, it may be concluded that tunable transconductors and grounded capacitors form the optimal minimal set of components necessary for building any active filter and, in particular, fully integrated active filters [1,2].…”

Automatic Synthesis of VLSI Layout for Analog Continuous-time Filters

“…II. SOFTWARE OVERVIEW OTACC initially was written by Martine Wedlake and Dr. W. RobertDaasch[14][15][16]. After receiving the initial prototype, my project was to add the necessary features to make OTACC a tool that could be successfully integrated into the filter design cycle.…”