Low-voltage digitally programmable current-mode universal biquadratic filter

This paper describes a digitally programmable current-mode universal biquadratic filter. It can realize all the standard types of biquadratic functions from the same topology. The filter types can be programmed digitally by the controlled CMOS switch pattern. Based on current-mode CMOS technology, the proposed filter is suitable for a mixed digital–analog LSI and is useful for low-voltage low-power high-frequency applications. Moreover, the circuit employs only two grounded capacitors that is very suitable for fully integrated circuit (IC) design. In addition, the filter frequency is tuned by simply changing the bias current of the filter. PSPICE simulation results based on the MOSIS 0.5μm level 3 model parameters are in agreement with the presented work.