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VLSI Testing
Published in Santanu Chattopadhyay, Thermal-Aware Testing of Digital VLSI Circuits and Systems, 2018
Logic BIST is a DFT technique in which the test-pattern generator and response analyzer become part of the chip itself. Figure 1.2 shows the structure of a typical logic BIST system. In this system, a test-pattern generator (TPG) automatically generates test patterns, which are applied to the circuit under test (CUT). The output-response analyzer (ORA) performs automatic space and time compaction of responses from the CUT into a signature. The BIST controller provides the BIST control signals, the scan enable signals, and the clock to coordinate complete BIST sessions for the circuit. At the end of BIST session, the signature produced by the ORA is compared with the golden signature (corresponding to the fault-free circuit). If the final space- and time-compacted signature matches the golden signature, the BIST controller indicates a pass for the circuit; otherwise it marks a fail.
System-on-a-Chip Design and Verification
Published in Nihal Kularatna, Electronic Circuit Design, 2017
These steps are needed to check for manufacturing errors during chip fabrication. Testing is the final process that verifies the accurate functional (and parametric, when analog blocks are involved or when the SoC is to be binned according to such parameters as maximum clock frequency) behavior of each fabricated chip, using functional test vectors specified by the designer. However, it is not easy to generate all the required functional test vectors or apply all the prepared vectors to each fabricated chip. As the time for testing each chip is reflected in the chip cost, the efficiency of testing, as defined by the fault coverage (i.e., the percentage of manufacturing faults that can be detected divided by the test vector length), is very important in the design of testing scenarios. To make testing easier, DFT is often incorporated in the synthesis step, which inserts a scan path apart from the functional logic path. ATPG generates test vectors according to the given fault coverage, typically based on stuck at 1 or 0 fault models.
Testability modeling for a remote monitoring system of marine diesel engine power plant
Published in Lin Liu, Automotive, Mechanical and Electrical Engineering, 2017
Xuedong Wen, Guo He, Kun Bi, Peng Zhang
RMASMDEPP is one of the most severe working environment and the most widely used in the monitoring and alarming system of ship platform. Under these circumstances, the ability to detect and isolate faults and the testability of the system are the important factors which restrict the performance of the power plant. DFT technology can greatly improve the ability of test, diagnosis and maintenance for large complex equipment. That is, it is the key technology to solve the problem of testing and diagnosis for RMASMDEPP. For DFT, The establishment of testability model is the basic work, which is also a hot research area. At present, both of Information-flow model and Multi-signal flow graph model are more general and more extensive studied.
Structural stability of SrZrO3 perovskite and improvement in electronic and optical properties by Ca and Ba doping for optoelectronic applications: a DFT approach
Published in Philosophical Magazine, 2019
S. S. A. Gillani, Riaz Ahmad, I. Zeba, Muhammad Rizwan, Muhammad Rafique, M. Shakil, Saqib Jabbar, M. Siddique
Optimisation of structure geometry is the most important step to get best DFT calculation results. For the calculation of single-point energy, first geometry is optimised for both pure and doped systems under 5 × 10−5 eVatom−1 self-consistent energy convergence accuracy. Moreover, residual forces during the optimisation of structure geometry were lower than 2 meV/A0. To proceed this step, first supercell of pure SZO was constructed and its ground state energy, when the structure is fully relaxed, was determined with GGA-PBE [31,32] and the most optimised structural constants are obtained. These calculated values are associated with already theoretically and experimentally reported results [8,18,26,36,37] (Table 1). Here we must keep in mind that the cubic structure of SZO is stable at temperatures higher than 1440 K [19], and for our calculations the effect of thermal expansion has not been taken. It is quite difficult to have a numerical estimation of the low-temperature lattice parameters for this phase because of the phase changes and nonlinearities. But it is estimated that, at low temperature, GGA-PBE somewhat overestimate the lattice parameters. There is less than 1% uncertainty in both theoretical and experimental values and this shows reliability and soundness of our calculations.
Spin–spin coupling constants in linear substituted HCN clusters
Published in Molecular Physics, 2019
Puspitapallab Chaudhuri, Lucas C. Ducati, Angsula Ghosh
Over the last few decades, nuclear magnetic resonance (NMR) spectroscopy has developed in a consistent manner, both theoretically and experimentally. Of late, it is one of the most important methods for structural characterisation of organic molecules. NMR spectroscopy is also used extensively to investigate the hydrogen-bonded molecular clusters. Hydrogen bonding between the molecules can produce large variations in the chemical and structural properties of the molecules providing important information about the nature of intermolecular interactions. Both ab initio and DFT methods have been employed to calculate the spin–spin coupling constants (SSCCs) for a variety of molecular systems. Since ab initio methods are computationally costlier than DFT, the latter has naturally become a more popular choice. DFT offers a good compromise between accuracy and computational cost. However, since a large number of density functionals and basis sets are available in the literature, it is sometimes challenging to choose the most appropriate model for the desired object of investigation.