A Field-Programmable Analog Array for high frequency OTA-C filters

Abstract

Of late Field-Programmable Gate arrays have become very popular because of their low cost and instant turnaround. However, extending the concept of field-programmability to analog circuits has been an arduous task because of the various issues that have to be taken care of in building a Field-Programmable Analog Array (FPAA). Compared to conventional metal-programmable arrays which require a final metalization step, a FPAA can be easily programmed within minutes to realize filters within a specified frequency range. Such a FPAA would be ideal for prototyping analog circuits and off-theshelf analog filters. This thesis deals with the design, development and difficulties involved in building such a FPAA targeted towards high frequency Operational Transconductance Amplifier (OTA)-Capacitor (C) filters. The various blocks of the OTA-C filter are mapped onto the FPAA blocks. Programmable switches in connection and switching blocks connect the various tracks in each channel to realize the interconnections. The flow schematic of a CAD system that obtains the user input specification and maps it onto the FPAA blocks is also proposed. Several test circuits were implemented on the FPAA and their performance studied. Test results of the fabricated programmable specification OTA are presented. Based on the simulation and fabricated results, the fea sibility of the field-programmable analog array for designing analog systems was demonstrated.