New Log-Domain First-Order Multifunction Filter Using MOSFETs in Weak Inversion

A new current-mode first-order log-domainmultifunction filter is presented in this paper. This filter has single inputand provides three outputs (low-pass, high-pass and all-pass) using a first-orderlow-pass filter and five of current mirrors as building blocks. The proposedfilter employs only MOSFETs and a grounded capacitor. The first-orderfilters are used in audio and video applications extensively. The MOSFETs ofthe core section are operated in weak inversion thereby making the circuit suitablefor low-voltage, low-power applications. The SPICE simulations have shown goodperformance of the proposed filter.