This paper presents a novel procedure for the implementation of digitally programmable switched-capacitor recursive (IIR) filters. The use of a number of zeros greater than the number of poles assures low sensitivity in the passband, being better than that obtained with an elliptic filter. Digital-to-analog conversion (DAC) techniques allow filter programming by controlling capacitor charge instead of adjusting a capacitor bank, reducing both silicon area and costs. Finally, multiplexing individual operational amplifiers among 2nd order FIR modules reduces the number of required op-amps and, consequently, power dissipation.
Filter design; Integrated circuit; Programmable filter; Recursive filters; Switched-capacitor filters
