Quantum-dot cellular automata (QCA) is one of
the most promising solutions to design ultra low-power and very high speed
digital circuits.In this paper an improved QCA full adder is
KEY WORD :
Full adder, Nano technology,
Quantum-dot cellular automata, QCA cell.
The digital circuits are designed using CMOS technology, But it is
difficult to design circuits with less number of transistors and with lower
power consumption based on Moore’s law.
To overcome these problems a new nanotechnology is invented that is
called quantum dot cellular automata. QCA has several advantages over CMOS
technology. Some of the advantages include faster switching speeds, high
density circuits and low power consumption. In QCA digital circuits are designed in nanometers scale now a days QCA
is gained high popularity because of creating, computing devices in the Nano
Full adder is
one of the most frequently used components in arithmetic units. Actually,
function of full adder is addition and also it is utilized as a core part in
other arithmetic operations. In this case, designing efficient QCA full adder
is a great solution to increase developing process of QCA arithmetic circuit
introduces less hardware complexity full adder using three input exclusive OR gate
(TIEO). It can be easy to extend serial adder as ripple carry adder. Using this
approach provides improved area and delay to other recent design.
QCA IN BRIEF :
consisting of quantum cells; each of the cells contains four dots which are
present in corners of QCA cell. The charge is localized in the dots. Also, the
cell consists of two mobile electrons that can tunnel between the dots.
Electron tunneling out of the cell is not possible due to the potential
barriers between cells. Two free electrons placed at the corners of the cells,
always diagonally due to Coulombic repulsion.