A CMOS field programmable analog array and its application in continuous-time OTA-C filter design

A general configurable analog block (CAB) is presented, which consists of the programmable OTA, programmable capacitor and MOSFET switches. Using the CABs, the universal tunable and field programmable analog array (FPAA) can be constructed, which can realize many signal-processing functions, including filters. A prototype 5/spl times/8 CAB array has been fabricated. The chip has also been configured to realize a programmable OTA-C filter. From the simulated and measured results it has been found that filters with frequencies from several kHz to a few MHz can be realized based on the proposed CAB and FPAA.

1. Introduction

In recent years Field Programmable Analog Arrays (FPAAs) have received great interest, as they can achieve similar benefits in analog circuit and system design as Field Programmable Gate Arrays (FPGA) have in digital counterpart. There have been some programmable analog circuits in the literature [1]–[13]. However general purpose FPAAs suitable for high frequency signal processing applications have not yet appeared. The structure of the proposed circuit is composed of 40 universal Configurable Analog Blocks (CABs) connected together to form a matrix. As an example of its application, a RLC-ladder based sixth-order band-pass OTA-C filter is presented.