Switched capacitor and active-RC filter layout using a parameterizable generator

An automatic macrocell generator has been developed and applied to the analog layout of switched-capacitor (SC) and active-RC filters. The generator consists of a process-independent generation procedure, a leafcell library, and a circuit description of the leafcells. The unit element arrays of the whole filter are generated together to minimize the array height of the entire filter macrocell, so that the area of the generated filter is as small as that of a manually laid out filter. Three SC filters and one active-RC filter were designed and fabricated by 1.5- mu m CMOS technology and successfully yielded a signal-to-noise (S/N) ratio of more than 70 dB with a quick turnaround time. >