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

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