A second-order log-domain bandpass filter for audio frequency applications

Log-domain filters have recently come into the limelight of the VLSI community as an important class of circuits for implementing continuous-time filters in the current domain. Some papers have discussed log-domain circuit analysis and some have addressed circuit synthesis. In this paper we describe synthesis of a second-order log-domain bandpass filter, address issues related to low-frequency (audio-frequency) filter design, and show experimental results from systems fabricated in standard 2 μm and 1.2 μm BiCMOS technologies