عنوان : Circuit Design with Multi-Input Majority Function for QCA and Nanotechnologies
بسمه تعالی زمان نصب در تابلوی اعلانات:
§ دفاع از رساله دکتری سمينار عمومي (Colloquium)
دفاع از پایاننامه کارشناسیارشد
سمينار تخصصي (Seminar)
سمينار تخصصي و مشورتي (Informal Seminar)
عنوان : Circuit Design with Multi-input Majority Function for QCA and Nanotechnologies
سخنران : عصام الخالدی
چکیده: After decades of the domination of the CMOS technology on the IC fabrication technologies new competitors are now raising, since the CMOS start reaching the physical limit. Many emerging technologies are suggested to replace CMOS. Great attention is paid to develop the nanotechnology fabrication techniques but few attempts were done to develop special design techniques for the emerging nanotechnologies. In this thesis the multi-input majority function is presented as a basic design tool for two of the nanotechnologies, QCA (Quantum Dot Cellular Automata) and CNFET (Carbon Nano Tube Field Effect Transistor) with two different approaches.
For CNFET the proposed approach is based on using multi-input majority function as a threshold logic gate. The proposed approach is used to illustrate a general form for the multi-inputs logic gates (AND, OR, NAND, and NOR). Also new design approach for the multi-input XOR suitable for nanotechnologies is presented and deployed to CNFET 5-input & 7-input XOR circuit. The results show good improvements in the speed and number of devices. The ( 4;2 ) compressor as a multi-input multi-output circuit is employed as example circuit to demonstrate the new approach. Two versions of transistor level design are presented for the proposed gate level design in the voltage and current modes. Simulation results show good improvement in the number of gate levels and the number of transistors (in another word the circuit area). In addition, in the current mode version of the ( 4;2 ) compressor a significant improvement in the speed of 84% is achieved. The process variation study for the proposed 7-input XOR gate good results show the good match between the proposed design approach and the CNFET technology.
For QCA the multi-input majority function is integrated into new 2-input and 3-input XOR designs to form a powerful logic design tools for the ESOP (Exclusive OR Sum Of Products) algorithm. The proposed XOR designs are used to create a single layer even parity generator with different word length up to 32-bits, full adder, and two forms of 5-2 compressor using QCA. All the presented designs are simulated with QCADesigner and shown superior results as compared to previously reported designs.
The PTM (Probabilistic Transfer Matrix) is used to inspect the reliability of multi-input majority function for QCA. This study conclude that the single-gate with multi-input Majority has the same reliability of its 3-input form. To extend the results to digital circuits, the full adder is used as a test bench. The results show the superiority of the full adder version designed with 5-input majority gate upon other designs from reliability point of view.