Mixed mode circuit design is the current trend in VLSI industry, where both analog and digital circuitry can be fabricated using standard digital CMOS technologies. However, these technologies do not lend themselves to analog design, requirting novel circuit design techniques that are compatible with standard CMOS processes. Consequently, over the last few decades Current-Mode (CM) processing has evolved as a novel design technique which has resulted in emergence of numerous analog building blocks. The operational transresistance amplifier (OTRA) is one among those. It is a high gain current input voltage output device which provides the advantages of current mode design techniques and can readily be used for voltage-mode applications.

This paper presents a new voltage mode Multi-Input Single Output (MISO) first order universal filter using single OTRA. The presented topology can be used to realize low-pass, high-pass and all-pass filter functions through appropriate input selections. The configuration is made fully integrated by implementing the resistors using matched transistors thereby reducing chip area. The proposed circuit is insensitive to parasitic capacitances and resistances due to internally grounded input terminals of OTRA. The effect of non-ideality of OTRA on the proposed circuit is also analysed. Functionality of the proposed configuration is verified through PSPICE simulations using 0.5 μm CMOS process parameters. The simulation results are in tune with the theoretical propositions.