High Performance Continuous-time Filters for Information Transfer Systems

High Performance Continuous-time Filters for InformationTransfer Systems. (August 2003)Ahmed Nader Mohieldin, B.Sc., Cairo University, Egypt;M.Sc., Cairo University, Egypt;Chair of Advisory Committee: Dr. Edgar Sánchez-Sinencio Vast attention has been paid to active continuous-time filters over the years. Thus asthe cheap, readily available integrated circuit OpAmps replaced their discrete circuitversions, it became feasible to consider active-RC filter circuits using large numbers ofOpAmps. Similarly the development of integrated operational transconductanceamplifier (OTA) led to new filter configurations. This gave rise to OTA-C filters, usingonly active devices and capacitors, making it more suitable for integration. The demandson filter circuits have become ever more stringent as the world of electronics andcommunications has advanced. In addition, the continuing increase in the operatingfrequencies of modern circuits and systems increases the need for active filters that canperform at these higher frequencies; an area where the LC active filter emerges. Whatmainly limits the performance of an analog circuit are the non-idealities of the usedbuilding blocks and the circuit architecture. This research concentrates on the designissues of high frequency continuous-time integrated filters.Several novel circuit building blocks are introduced. A novel pseudo-differentialfully balanced fully symmetric CMOS OTA architecture with inherent common-mode