A new approach to bypass wire crossing problem in QCA nano technology

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ali Majeed ◽  
Esam Alkaldy

Purpose This study aims to replace current multi-layer and coplanar wire crossing methods in QCA technology to avoid fabrication difficulties caused by them. Design/methodology/approach Quantum-dot cellular automata (QCA) is one of the newly emerging nanoelectronics technology tools that is proposed as a good replacement for complementary metal oxide semiconductor (CMOS) technology. This technology has many challenges, among them being component interconnection and signal routing. This paper will propose a new wire crossing method to enhance layout use in a single layer. The presented method depends on the central cell clock phase to enable two signals to cross over without interference. QCADesigner software is used to simulate a full adder circuit designed with the proposed wire crossing method to be used as a benchmark for further analysis of the presented wire crossing approach. QCAPro software is used for power dissipation analysis of the proposed adder. Findings A new cost function is presented in this paper to draw attention to the fabrication difficulties of the technology when designing QCA circuits. This function is applied to the selected benchmark circuit, and the results show good performance of the proposed method compared to others. The improvement is around 59, 33 and 75% compared to the best reported multi-layer wire crossing, coplanar wire crossing and logical crossing, respectively. The power dissipation analysis shows that the proposed method does not cause any extra power consumption in the circuit. Originality/value In this paper, a new approach is developed to bypass the wire crossing problem in the QCA technique.

Circuit World ◽  
2019 ◽  
Vol 45 (4) ◽  
pp. 300-310
Author(s):  
Piyush Tankwal ◽  
Vikas Nehra ◽  
Sanjay Prajapati ◽  
Brajesh Kumar Kaushik

Purpose The purpose of this paper is to analyze and compare the characteristics of hybrid conventional complementary metal oxide semiconductor/magnetic tunnel junction (CMOS/MTJ) logic gates based on spin transfer torque (STT) and differential spin Hall effect (DSHE) magnetic random access memory (MRAM). Design/methodology/approach Spintronics technology can be used as an alternative to CMOS technology as it is having comparatively low power dissipation, non-volatility, high density and high endurance. MTJ is the basic spin based device that stores data in form of electron spin instead of charge. Two mechanisms, namely, STT and SHE, are used to switch the magnetization of MTJ. Findings It is observed that the power consumption in DSHE based logic gates is 95.6% less than the STT based gates. DSHE-based write circuit consumes only 5.28 fJ energy per bit. Originality/value This paper describes how the DSHE-MRAM is more effective for implementing logic circuits in comparison to STT-MRAM.


Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kalpana Kasilingam ◽  
Paulchamy Balaiah

Purpose The nano-router would be a mastery device for providing high-speed data delivery. Here nano-router with a space-efficient crossbar scheduler is used for making absolutely less consumption in power. Design/methodology/approach In the emerging modern technology, every one of us is expecting a delivery of data at a high speed. To achieve high-speed delivery the authors are using the router. The router used here is at nanoscale reading which provides a compact size. Findings This can be implemented using the modern tools called Quantum-dot Cellular Automata (QCA) which is operated without the use of a transistor. As conventional complementary metal oxide semiconductor (CMOS) designs have some limitations such as low density, high power consumption and requirement of a large area. Research limitations/implications To overcome these limitations the QCA is used. It characterizes capability is used to substituting CMOS technology. The round-robin fashion is used in a high-speed space-efficient crossbar scheduler. Practical implications The simulation of the planned circuit with notional information established the practical identity of the scheme. Social implications The proposed nano router can be stimulated in the QCA environment using the QCADesigner tool and the power of the router can be calculated with the QCADesigner–E tool. Originality/value The proposed nano router can be stimulated in the QCA environment using the QCADesigner tool and the power of the router can be calculated with the QCADesigner–E tool. In this work, the performance of the router can be done in both the QCA environment and CMOS technology.


2020 ◽  
Vol 20 (8) ◽  
pp. 4793-4798
Author(s):  
Daseul Yoon ◽  
Ji-Hoon Kim ◽  
Sung Min Park

This paper presents a novel symmetric current-conveyor transimpedance amplifier (SCC-TIA) implemented in a 0.13-μm CMOS technology for the applications of LiDAR systems, where a modifiedcascode configuration is newly proposed for input current buffer to deliver the photo-currents to the following voltage-mode inverter TIA without signal loss. Measured results of the proposed SCC-TIA demonstrate 69-dBΩ transimpedance gain, 410-MHz bandwidth, 13-pA/sqrt (Hz) average noise current spectral density, and 20-mW power dissipation from a single 1.2-V supply. Chip core occupies the area of 280×130 μm2.


2019 ◽  
Vol 39 (1) ◽  
pp. 47-59 ◽  
Author(s):  
Abbas Rezaei

Quantum-dot cellular automata (QCA) is a developing nanotechnology, which seems to be a good candidate to replace the conventional complementary metal-oxide-semiconductor (CMOS) technology. The QCA has the advantages of very low power dissipation, faster switching speed, and extremely low circuit area, which can be used in designing nanoscale reversible circuits. In this paper, the new efficient QCA implementations of the basic reversible Gates such as: CNOT, Toffoli, Feynman, Double Feynman, Fredkin, Peres, MCL, and R Gates are presented based on the straight interactions between the QCA cells. Also, the designs of 4-Bit reversible parity checker and 3-bit reversible binary to Grey converter are introduced using these optimized reversible Gates. The proposed layouts are designed and simulated using QCADesigner software. In comparison with previous QCA designs, the proposed layouts are implemented with the minimum area, minimum number of cells, and minimum delay without any wire-crossing techniques. Also, in comparison with the CMOS technology, the proposed layouts are more efficient in terms of the area and power. Therefore, our designs can be used to realize quantum computation in ultralow power computer communication.


2021 ◽  
Vol 17 ◽  
Author(s):  
Syed Farah Naz ◽  
Sadat Riyaz ◽  
Vijay Kumar Sharma

Background: The human ken and understanding about esoteric phenomenon develops the period from space to the sub-atomic level. The passion to further explore the unexplored domains and dimensions boosts the human advancement in a cyclic way. A significant part of such passion follows in the electronics industry. Moore’s law is reaching the practical limitations because of further scaling of metal oxide semiconductor (MOS) devices. The need of a more dexterous and effective technology approach is demanded. Quantum-dot cellular automata (QCA) is an emerging technology which avoids the physical limitations of the MOS device. QCA is a dynamic computational transistor paradigm that addresses device density, power, operating frequency and interconnection problems. It requires an extensive study to know the fundamentals of logic implementation. Objective: Immense research and experiments due same vigor led to the evolving nanotechnology and a feasible alternative to complementary metal oxide semiconductor (CMOS) technology. A comprehensive study is presented in the paper to enhance the basics of QCA technology and the way of implementation of the logic circuits. Different existing circuits using QCA technology are discussed and compared for different parameters. Methods: Scaling the devices can reduce the power consumption of the MOS device. Quantum dots are nanostructures made from semi-conductive conventional materials. It is possible to model these constructions as 3-dimensional (3D) quantum energy wells. Logical operations and data movement are performed using Columbic interaction between nearby QCA cells instead of current flow. Results: The focus of this review paper is to study the trends which have been proposed and compared the designs for various digital circuits. The performance of different circuits such as XOR, adder, reversible gates and flip-flops are provided. Different logic circuits are compared on the parameters such as cell count, area and latency. At least 10 QCA cells are used for the XOR gate with 1 clock latency. Minimum 44 QCA cells are required to make a full adder with 1.25 clock latency.


The paper proposes a Montgomery Modular Multiplier (MMM) using a simple and efficient Montgomery multiplication algorithm. Here a modification in the form of using hybrid full adders in the Carry Save adder is proposed. The hybrid full adder is designed using a conventional Complementary Metal Oxide Semiconductor and transmission gate logic. There is about 54% and 55% reduction of area (no. of components) in Radix 2 MMM and Semi-Carry-Save (SCS) based MMM with hybrid full adders. There is significant reduction in the power dissipation of 52% for Radix 2 MMM and 46% of SCS based MMM when hybrid adders are used instead of C-CMOS Full-Adders. The delay is also reduced by 47% in SCS based MMM as compared to that of Radix 2 MMM. The software used are Xilinx ISE 14.2 and Mentor Graphics Pyxis Schematic in 180-nm technology.


2009 ◽  
Vol 17 (9) ◽  
pp. 1267-1274 ◽  
Author(s):  
Liang Zhang ◽  
John M. Wilson ◽  
Rizwan Bashirullah ◽  
Lei Luo ◽  
Jian Xu ◽  
...  

This paper describes a differential current-mode bus architecture based on driver pre-emphasis for on-chip global interconnects that achieves high-data rates while reducing bus power dissipation and improving signal delay latency. The 16-b bus core fabricated in 0.25-mum complementary metal-oxide-semiconductor (CMOS) technology attains an aggregate signaling data rate of 32 Gb/s over 5-10-mm-long lossy interconnects. With a supply of 2.5 V, 25.5-48.7-mW power dissipation was measured for signal activity above 0.1, equivalent to 0.80-1.52 pJ/b. This work demonstrates a 15.0%-67.5% power reduction over a conventional single-ended voltage-mode static bus while reducing delay latency by 28.3% and peak current by 70%. The proposed bus architecture is robust against crosstalk noise and occupies comparable routing area to a reference static bus design.


2020 ◽  
Vol 10 (4) ◽  
pp. 534-547
Author(s):  
Chiradeep Mukherjee ◽  
Saradindu Panda ◽  
Asish K. Mukhopadhyay ◽  
Bansibadan Maji

Background: The advancement of VLSI in the application of emerging nanotechnology explores quantum-dot cellular automata (QCA) which has got wide acceptance owing to its ultra-high operating speed, extremely low power dissipation with a considerable reduction in feature size. The QCA architectures are emerging as a potential alternative to the conventional complementary metal oxide semiconductor (CMOS) technology. Experimental: Since the register unit has a crucial role in digital data transfer between the electronic devices, such study leading to the design of cost-efficient and highly reliable QCA register is expected to be a prudent area of research. A thorough survey on the existing literature shows that the generic models of Serial-in Serial Out (SISO), Serial-in-Parallel-Out (SIPO), Parallel-In- Serial-Out (PISO) and Parallel-in-Parallel-Out (PIPO) registers are inadequate in terms of design parameters like effective area, delay, O-Cost, Costα, etc. Results: This work introduces a layered T gate for the design of the D flip flop (LTD unit), which can be broadly used in SISO, SIPO, PISO, and PIPO register designs. For detection and reporting of high susceptible errors and defects at the nanoscale, the reliability and defect tolerant analysis of LTD unit are also carried out in this work. The QCA design metrics for the general register layouts using LTD unit is modeled. Conclusion: Moreover, the cost metrics for the proposed LTD layouts are thoroughly studied to check the functional complexity, fabrication difficulty and irreversible power dissipation of QCA register layouts.


2021 ◽  
Vol 50 (16) ◽  
pp. 5540-5551
Author(s):  
Almudena Notario-Estévez ◽  
Xavier López ◽  
Coen de Graaf

This computational study presents the molecular conduction properties of polyoxovanadates V6O19 (Lindqvist-type) and V18O42, as possible successors of the materials currently in use in complementary metal–oxide semiconductor (CMOS) technology.


Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 551
Author(s):  
Zhongjian Bian ◽  
Xiaofeng Hong ◽  
Yanan Guo ◽  
Lirida Naviner ◽  
Wei Ge ◽  
...  

Spintronic based embedded magnetic random access memory (eMRAM) is becoming a foundry validated solution for the next-generation nonvolatile memory applications. The hybrid complementary metal-oxide-semiconductor (CMOS)/magnetic tunnel junction (MTJ) integration has been selected as a proper candidate for energy harvesting, area-constraint and energy-efficiency Internet of Things (IoT) systems-on-chips. Multi-VDD (low supply voltage) techniques were adopted to minimize energy dissipation in MRAM, at the cost of reduced writing/sensing speed and margin. Meanwhile, yield can be severely affected due to variations in process parameters. In this work, we conduct a thorough analysis of MRAM sensing margin and yield. We propose a current-mode sensing amplifier (CSA) named 1D high-sensing 1D margin, high 1D speed and 1D stability (HMSS-SA) with reconfigured reference path and pre-charge transistor. Process-voltage-temperature (PVT) aware analysis is performed based on an MTJ compact model and an industrial 28 nm CMOS technology, explicitly considering low-voltage (0.7 V), low tunneling magnetoresistance (TMR) (50%) and high temperature (85 °C) scenario as the worst sensing case. A case study takes a brief look at sensing circuits, which is applied to in-memory bit-wise computing. Simulation results indicate that the proposed high-sensing margin, high speed and stability sensing-sensing amplifier (HMSS-SA) achieves remarkable performance up to 2.5 GHz sensing frequency. At 0.65 V supply voltage, it can achieve 1 GHz operation frequency with only 0.3% failure rate.


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