PROGRAMMABLE SWITCHED-CURRENT WAVE ANALOG FILTERS

This paper presents a methodology to realize Programmable Switched-Cur rent filters. A universal wave filter structure is built based on a lo w-pass (LP) to band-pass (BP) frequency transformation in the z-domain that allows obtaining different filtering functions from a single' lo w-pass reference filter without altering the global circuit topology. Two different parameters, modified by changing the gain of current mir rors, independently control the filter bandwidth and center frequency. A 2.88-mm2 IC prototype has been fabricated in a 1.6-mum CMOS digital technology that is capable of implementing three LP's (and their thre e complementary HP's) and nine BP's (and their nine complementary BR) Chebyschev filters. The realization of the 24 filtering functions requ ires less than 15% of additional area than that required to implement only one BP function. The chip operates from a 5-V supply, dissipates 0.83 mW/pole, and met the expected performance levels for all filter f unctions.