Abstract—Different logic gates like MV, NOT, AOI, NNI etc under QCA nanotechnology are introduced. NNI gate is highly effective regarding space and speed consideration. Any Boolean functions are synthesized by MV and NNI gates or simply NNI gates alone, eliminating inverter (NOT) gate. A new method for realizing adder circuit in binary reversible logic is invented. This procedure synthesizes for a more efficient designing adder circuits with little “garbage”. The method is used in a classical logic. I use only 2-inputs and 2-outputs AND-NAND and OR-NOR cells designed on QCA technology. It admits a recursive construction. Ultimately a general equation for the minimum number of gates required to an arbitrary number of input variables, causing synthesis of adder circuits, is achieved. It provides a significant reduction in hardware cost and switching delay compared to the other existing techniques. All other type of combinational circuits like subtractor, multiplier, divisor, multiplexer, encoder, comparator etc can be designed by the adder circuit only.

Index Terms—Adder Circuit Design, 2-Inputs and 2-Outputs AND-NAND (A-NA) gate, And-Or-Inverter (AOI) gate, Majority Voter (MV) gate, Moore’s Law, Nand-Nor-Inverter (NNI) gate, 2-Inputs and 2-Outputs OR-NOR (O-NO) gate.

Pijush Kanti Bhattacharjee is an Assistant Professor in the Department of Electronics and Communication Engineering, Bengal Institute of Technology and Management, Santiniketan, P.O. Doranda, West Bengal, Pin-731236, India. He was an Ex Asssitant Director in the Department of Telecommunications (DoT), Government of India, India. He has possessed vast working experience in the field of Telecommunications including Mobile Communications, Image Processing, VLSI etc during last 29 years. He is a member of IACSIT, Singapore; CSTA, USA; IAEng, Hongkong. (phone: +91-33-25954148; email: pijushbhatta_6@hotmail.com).

Cite: Pijush Kanti Bhattacharjee, "Digital Combinational Circuits Design By QCA Gates," International Journal of
Computer and Electrical Engineering vol. 2, no. 1, pp. 67-72, 2010.