Low Voltage Low Frequency Continuous Time CMOS Antialiasing Filters

In the paper design considerations for low frequency antialiasing filters suitable for low voltage modern CMOS technology. Two circuit implementations of Sallen-Key architecture are presented. First uses conventional approach and utilizes long tail pair as amplifying block, while the second exploits CMOS inverters for the same purpose and thus its supply requirements are lower. In both a tricky solution of active resistor formed by transmission gates with long MOSFETs is used. Simulation results are presented and discussed.