A New Universal Second-Order Filter using Configurable Analog Building Blocks (CABs) for Filed-Programmable Analogue Arrays

Abstract

In this paper, the design of a universal second-order filter using configurable analog blocks (CABs) for field programmable analog arrays is presented. The configurable blocks are capable of performing integration, differentiation, amplification, log, anti-log, add and negate functions. To maintain high frequency operation, the programmability and configurability of the blocks are achieved by digitally modifying the block's biasing conditions. Using at most four CABs, this article shows that it is possible to design a versatile second-order filter realizing all the standard five filter functions; lowpass, highpass, bandpass, notch and allpass. SPICE simulation results using practical bipolar junction transistor (BJT) parameters confirm the feasibility of using the CABs in designing second-order filters.