Fault Resistant Coplanar QCA Full Adder-Subtractor Using Clock Zone-Based Crossover
IETE JOURNAL OF RESEARCH
Authors: Marshal, R.; Lakshminarayanan, G.
Abstract
Adders and Subtractor are an integral part of every digital information processing system. In general, it is always preferred to have a unified hardware that can perform both operations to reduce the area of circuits. The transistor technology is facing several difficulties to cope up with the targets set by Moore's law. Researchers have started to focus on finding alternatives. Quantum-dot Cellular Automata nanotechnology is suggested by the researchers for circuit design at Nanoscale levels. A full adder-subtractor circuit using clock zone and multilayer crossover are proposed in this work. The results show that they have minimal cells and area. The fault tolerance capacity of the designs to missing cell defects is also analyzed. The full adder-subtractor coplanar design is 86.7% fault resistant and the multilayer design is 76.5% fault resistant. The Coherence vector simulation engine is used to perform all the simulations in QCA Designer.
Design and initial characterization of MIC4, the monolithic active pixel sensor prototype for CEPC vertex detector
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
Authors: Ren, Weiping; Zhang, Dongliang; Sun, Xiangming; Huang, Guangming; Liu, Jun; Xiao, Le; Gao, Chaosong; Pei, Hua; Huang, Xing; Zhou, Wei; You, Bihui; Yang, Ping
Abstract
The Circular Electron Positron Collider (CEPC) is proposed as a Higgs factory to produce adequate events, which are the basis for high-precision measurements of the Higgs boson. The vertex detector in the CEPC should meet the requirements of a low material budget, high spatial resolution, fast readout speed and low power consumption. A monolithic active pixel sensor (MAPS) has been selected as the most promising technology for the vertex detector. The MIC4 sensor is the first prototype developed within the preliminary R&D activities of the CEPC vertex detector. It has been implemented in the TowerJazz 180 nm CMOS image sensor (CIS) process. It measures 3.1 mm x 4.6 mm and features a 128 row x 64 column pixel array with a pixel pitch of 25 mu m. In this work, a binary front-end has been designed for a compact pixel combined with a sparsified readout circuitry. Each pixel is composed of an amplifier, a shaper, a discriminator and digital logic. A new asynchronous zero-suppression data-driven readout circuit architecture is proposed and implemented in MIC4. We have performed some initial tests on this chip and obtained detailed results. The front-end features a peaking time below 1 mu s, a shaping time less than 3 mu s, a charge threshold of approximately 100 e(-), an average temporal noise (TN) of 6 e(-) and a fixed pattern noise (FPN) of 36 e(-). The addresses of the fired pixels can be readout in the digital part of the chip at a clock running at 30 MHz with the new data-driven readout circuit architecture. The hit map under Fe-55 X-ray exposure shows that the sensor designed in MIC4 works well. The probability of single event latch-up (SEL) sigma(SEL) is 1.02 x 10(-6) cm(2) at a linear energy transfer (LET) of 20.05 MeV cm(2)/mg.