An NMOS analog building block for telecommunication applications

In this paper an NMOS mask programmable building block chip, capable of up to 22 poles of switched-capacitor (SC) filtering is described. Although the major portion of the chip is devoted to active-SC filtering, such functions as antialiasing, reconstruction, and threshold detection can also be performed on chip. In addition, the chip includes an oscillator and a number of flip-flops and gates, so that with the addition of an external crystal all the requisite nonoverlapping clock signals can be internally generated. The specific functions realized by the building block