Power Droop Reduction In Logic BIST By Scan Chain Reordering

Significant peak power (PP), thus power droop (PD), during test is a serious concern for modern, complex ICs. In fact, the PD originated during the application of test vectors may produce a delay effect on the circuit under test signal transitions. This event may be erroneously recognized as presence of a delay fault, with consequent generation of an erroneous test fail, thus increasing yield loss. Several solutions have been proposed in the literature to reduce the PD during test of combinational ICs, while fewer approaches exist for sequential ICs. In this paper, we propose a novel approach to reduce peak power/power droop during test of sequential circuits with scan-based Logic BIST. In particular, our approach reduces the switching activity of the scan chains between following capture cycles. This is achieved by an original generation and arrangement of test vectors. The proposed approach presents a very low impact on fault coverage and test time

Testing for delay defects utilizing test data compression techniques

textAs technology shrinks new types of defects are being discovered and new fault models are being created for those defects. Transition delay and path delay fault models are two such models that have been created, but they still fall short in that they are unable to obtain a high test coverage of smaller delay defects; these defects can cause functional behavior to fail and also indicate potential reliability issues. The first part of this dissertation addresses these problems by presenting an enhanced timing-based delay fault testing technique that incorporates the use of standard delay ATPG, along with timing information gathered from standard static timing analysis. Utilizing delay fault patterns typically increases the test data volume by 3-5X when compared to stuck-at patterns. Combined with the increase in test data volume associated with the increase in gate count that typically accompanies the miniaturization of technology, this adds up to a very large increase in test data volume that directly affect test time and thus the manufacturing cost. The second part of this dissertation presents a technique for improving test compression and reducing test data volume by using multiple expansion ratios while determining the configuration of the scan chains for each of the expansion ratios using a dependency analysis procedure that accounts for structural dependencies as well as free variable dependencies to improve the probability of detecting faults. Finally, this dissertation addresses the problem of unknown values (X’s) in the output response data corrupting the data and degrading the performance of the output response compactor and thus the overall amount of test compression. Four techniques are presented that focus on handling response data with large percentages of X’s. The first uses X-canceling MISR architecture that is based on deterministically observing scan cells, and the second is a hybrid approach that combines a simple X-masking scheme with the X-canceling MISR for further gains in test compression. The third and fourth techniques revolve around reiterative LFSR X-masking, which take advantage of LFSR-encoded masks that can be reused for multiple scan slices in novel ways.Electrical and Computer Engineerin

Self-Test Mechanisms for Automotive Multi-Processor System-on-Chips

L'abstract è presente nell'allegato / the abstract is in the attachmen

A MODIFIED FAULT COVERAGE ARCHITECTURE FOR A LOW POWER BIST TEST PATTERN GENERATOR USING LP-LFSR

This paper proposes low power pseudo random Test Pattern generation .This test pattern is run on the circuit under test for desired fault coverage. The power consumed by the chip under test is a measure of the switching activity of the logic inside the chip which depends largely on the randomness of the applied input stimulus. Reduced correlation between the successive vectors of the applied stimulus into the circuit under test can result in much higher power consumption by the device than the budgeted power. A new low power pattern generation technique is implemented using a modified conventional Linear Feedback Shift Register which can perform fault analysis and reduce the power of a circuit during test by generating three intermediate patterns between the random patterns by reducing the hardware utilization. The goal of having intermediate patterns is to reduce the transitional activities of Primary Inputs (PI) which eventually reduces the switching activities inside the Circuit under Test (CUT) and hence power consumption is also reduced without any penalty in the hardware resources

FPGA ARCHITECTURE AND VERIFICATION OF BUILT IN SELF-TEST (BIST) FOR 32-BIT ADDER/SUBTRACTER USING DE0-NANO FPGA AND ANALOG DISCOVERY 2 HARDWARE

The integrated circuit (IC) is an integral part of everyday modern technology, and its application is very attractive to hardware and software design engineers because of its versatility, integration, power consumption, cost, and board area reduction. IC is available in various types such as Field Programming Gate Array (FPGA), Application Specific Integrated Circuit (ASIC), System on Chip (SoC) architecture, Digital Signal Processing (DSP), microcontrollers (μC), and many more. With technology demand focused on faster, low power consumption, efficient IC application, design engineers are facing tremendous challenges in developing and testing integrated circuits that guaranty functionality, high fault coverage, and reliability as the transistor technology is shrinking to the point where manufacturing defects of ICs are affecting yield which associates with the increased cost of the part. The competitive IC market is pressuring manufactures of ICs to develop and market IC in a relatively quick turnaround which in return requires design and verification engineers to develop an integrated self-test structure that would ensure fault-free and the quality product is delivered on the market. 70-80% of IC design is spent on verification and testing to ensure high quality and reliability for the enduser. To test complex and sophisticated IC designs, the verification engineers must produce laborious and costly test fixtures which affect the cost of the part on the competitive market. To avoid increasing the part cost due to yield and test time to the end-user and to keep up with the competitive market many IC design engineers are deviating from complex external test fixture approach and are focusing on integrating Built-in Self-Test (BIST) or Design for Test (DFT) techniques onto IC’s which would reduce time to market but still guarantee high coverage for the product. Understanding the BIST, the architecture, as well as the application of IC, must be understood before developing IC. The architecture of FPGA is elaborated in this paper followed by several BIST techniques and applications of those BIST relative to FPGA, SoC, analog to digital (ADC), or digital to analog converters (DAC) that are integrated on IC. Paper is concluded with verification of BIST for the 32-bit adder/subtracter designed in Quartus II software using the Analog Discovery 2 module as stimulus and DE0-NANO FPGA board for verification

Dynamic scan chains : a novel architecture to lower the cost of VLSI test

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.Includes bibliographical references (p. 61-64).Fast developments in semiconductor industry have led to smaller and cheaper integrated circuit (IC) components. As the designs become larger and more complex, larger amount of test data is required to test them. This results in longer test application times, therefore, increasing cost of testing each chip. This thesis describes an architecture, named Dynamic Scan, that allows to reduce this cost by reducing the test data volume and, consequently, test application time. The Dynamic Scan architecture partitions the scan chains of the IC design into several segments by a set of multiplexers. The multiplexers allow bypassing or including a particular segment during the test application on the automatic test equipment. The optimality criteria for partitioning scan chains into segments, as well as a partitioning algorithm based on this criteria are also introduced. According to our experimental results Dynamic Scan provides almost a factor of five reduction in test data volume and test application time. More theoretical results reach as much as ten times the reductions compared to the classical scan methodologies.by Nodari S. Sitchinava.M.Eng

REALIZATION OF LOW TRANSITION BASED PRPG FOR POWER OPTIMIZED APPLICATIONS

This paper proposes low power pseudo random test pattern generator. This produces the necessary test patterns which are used for running the circuit under test for detecting faults. Power consumption of the circuit under test is measured by switching activity of the inside logic which depends on the randomness of applied stimulus. Power consumption is greatly increased due to the reduction of correlation between the successive vectors of applied stimulus. A modified conventional linear feedback shift register is implemented for reducing power of circuit under test by generating the patterns by reducing the utilization of hard ware. The main intension of producing intermediate patterns is to reduce the conventional activity of primary inputs (PI) that which reduces the switching activities inside the CUT and by this power consumption is reduced without using huge hardware

Built-In Self Test (BIST) for Realistic Delay Defects

Testing of delay defects is necessary in deep submicron (DSM) technologies. High coverage delay tests produced by automatic test pattern generation (ATPG) can be applied during wafer and package tests, but are difficult to apply during the board test, due to limited chip access. Delay testing at the board level is increasingly important to diagnose failures caused by supply noise or temperature in the board environment. An alternative to ATPG is the built-in self test (BIST). In combination with the insertion of test points, BIST is able to achieve high coverage of stuck-at and transition faults. The quality of BIST patterns on small delay defects is an open question. In this work we analyze the application of BIST to small delay defects using resistive short and open models in order to estimate the coverage and correlate the coverage to traditional delay fault models