Abstract: A general purpose active filter which can be fabricated as a single, monolithic IC. The IC includes two independent filter building blocks. Each filter block includes a pair of serially connected summers and a pair of serially connected switched capacitor positive integrators connected to the serial output of the summers. The IC further includes clock interface circuitry for receiving and conditioning first and second external clock signals. The interface circuitry drives the switches of the positive integrators of each filter block with one of the first and second conditioned clock signals. A plurality of input and output leads are interconnected with the components of each filter block to permit the filter blocks to be separately configured to perform various second order filter functions. The filter blocks may be tuned according to external resistance ratios and/or according to the frequencies of the external clock signals.