Design of Novel Coplanar Counter Circuit in Quantum Dot Cellular Automata Technology

One of the emerging technology that can be used for replacing CMOS technology is Quantum-dot Cellular Automata (QCA) technology. Counter circuits are widely used circuits in the design of digital circuits. This paper presents and evaluates circuits for 2-, 3-, 4-, and 5-bit coplanar counter in the QCA technology. The designed QCA coplanar counter circuits are based on the modified D-Flip-Flop (D-FF) circuit that is designed in this paper. The designed QCA circuits are implemented and verified by using QCADesigner tool version 2.0.3. The results show that the designed circuits for 2-, 3-, 4-, and 5-bit coplanar counter contain 44 (0.03 μm²), 93 (0.07 μm²), 160 (0.13 μm²), and 245 (0.2 μm²) quantum cells (area). The comparison results indicate that the designed circuits have advantages compared to other QCA circuits in terms of cost, area, and cell count.

     

Towards Multilayer QCA SISO Shift Register Based on Efficient D-FF Circuits

Quantum-dot Cellular Automata (QCA) is a new technology for replacing CMOS technology at nano-scale dimansion. Shift registers have commonly used circuit in the digital circuits design. In this paper, a new 3-bit Serial Input-Serial Output (SISO) QCA shift register is presented. The proposed circuit uses 3 novel D-Flip-Flops (D-FFs) that are developed in this paper. The proposed circuits are implemented by using QCADesigner tool version 2.0.3. The developed QCA SISO shift register has 120 cells and 0.03 μm² area. The results show that the developed circuits have advantages compared to other QCA circuits in terms of area.     

Design of Low-Complexity and High-Speed Coplanar Four-Bit Ripple Carry Adder in QCA Technology

Quantum-dot Cellular Automata (QCA) technology is a suitable technology to replace CMOS technology due to low-power consumption, high-speed and high-density devices. Full adder has an important role in the digital circuit design. This paper presents and evaluates a novel single-layer four-bit QCA Ripple Carry Adder (RCA) circuit. The developed four-bit QCA RCA circuit is based on novel QCA full adder circuit. The developed circuits are simulated using QCADesigner tool version 2.0.3. The simulation results show that the developed circuits have advantages in comparison with existing single-layer and multilayer circuits in terms of cell count, area occupation and circuit latency.     

Novel Efficient Circuit Design for Multilayer QCA RCA

The novel emerging technology, QCA technology, is a candidate for replacing CMOS technology. Full Adder (FA) circuits are also widely used circuits in arithmetic circuits design. In this paper, two new multilayer QCA architectures are presented: one-bit FA and 4-bit Ripple Carry Adder (RCA). The designed one-bit multilayer FA architecture is based on a new XOR gate architecture. The designed 4-bit multilayer QCA RCA is also developed based on the designed one-bit multilayer QCA FA. The functionality of the designed architectures are verified using QCADesigner tool. The results indicate that the designed architecture for 4-bit multilayer QCA RCA requires 5 clock phases, 125 QCA cells, and 0.17 μm² area. The comparison results confirm that the designed architectures provide improvements compared with other adder architectures in terms of cost, cell count, and area.