A new current-mode matrix-like universal filter using configurable analog blocks (CABs) for field-programmable analog arrays

In this paper, the design of a matrix-like universal second-order filter using configurable analog blocks (CABs) for field programmable analog arrays is presented. The CABs 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 CABs are achieved by digitally modifying the block's biasing conditions. Using at most two CABs, in addition to current mirrors, this paper shows that it is possible to design versatile second-order filter realizing all the standard five filter functions; lowpass, highpass, babdpass, notch and allpass. SPICE simulation results obtained using practical bipolar junction transistor (BJT) parameters confirm the feasibility of using CABs In designing matrix-like universal second-order filters.