Evaluation and synthesis of ultra narrow band switched-capacitor-filters employing multirate techniques

The problem of designing ultra-narrowband switched-capacitor filters (relative bandwidth <0.1%) using current design techniques is considered. These are evaluated using a statistical simulation approach to quantify the effects of mismatch in the multipath structures used. The limitations of available techniques are highlighted, and a structure that is significantly less sensitive to mismatch is proposed. As a corollary, a pseudo-N-path building block that has especially low sensitivity to finite amplifier gain-bandwidth product is introduced