A low-voltage CMOS 1-Hz low-pass filter

In this paper, we present a technique for the implementation of low cut-off frequency filters based on the use of a second generation current conveyor (CCII) employed as a capacitive multiplier, whose multiplicative effect has been extended successfully at very low frequencies. A first-order 1-Hz low-pass filter was designed to demonstrate the compatibility of the technique with standard IC technologies. The proposed implementation was simulated in SPICE with a 0.5-/spl mu/m CMOS Alcatel Mietec technology and uses a supply voltage as low as 1.5 V. A very good agreement with the theoretical results is found.