LFSR-coded test patterns for scan designs
01 Jan 1991-pp 237-242
About: The article was published on 1991-01-01 and is currently open access. It has received 519 citations till now.
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TL;DR: This paper presents a novel test-data volume-compression methodology called the embedded deterministic test (EDT), which reduces manufacturing test cost by providing one to two orders of magnitude reduction in scan test data volume and scan test time.
Abstract: This paper presents a novel test-data volume-compression methodology called the embedded deterministic test (EDT), which reduces manufacturing test cost by providing one to two orders of magnitude reduction in scan test data volume and scan test time. The presented scheme is widely applicable and easy to deploy because it is based on the standard scan/ATPG methodology and adopts a very simple flow. It is nonintrusive as it does not require any modifications to the core logic such as the insertion of test points or logic bounding unknown states. The EDT scheme consists of logic embedded on a chip and a new deterministic test-pattern generation technique. The main contributions of the paper are test-stimuli compression schemes that allow us to deliver test data to the on-chip continuous-flow decompressor. In particular, it can be done by repeating certain patterns at the rates, which are adjusted to the requirements of the test cubes. Experimental results show that for industrial circuits with test cubes with very low fill rates, ranging from 3% to 0.2%, these schemes result in compression ratios of 30 to 500 times. A comprehensive analysis of the encoding efficiency of the proposed compression schemes is also provided.
529 citations
Book•
01 Jul 2006
TL;DR: This book is a comprehensive guide to new DFT methods that will show the readers how to design a testable and quality product, drive down test cost, improve product quality and yield, and speed up time-to-market and time- to-volume.
522 citations
TL;DR: A new scheme for built-in test that uses multiple-polynomial linear feedback shift registers (MP-LFSR's) and an implicit polynomial identification reduces the number of extra bits per seed to one bit is presented.
Abstract: We propose a new scheme for built-in test (BIT) that uses multiple-polynomial linear feedback shift registers (MP-LFSR's). The same MP-LFSR that generates random patterns to cover easy to test faults is loaded with seeds to generate deterministic vectors for difficult to test faults. The seeds are obtained by solving systems of linear equations involving the seed variables for the positions where the test cubes have specified values. We demonstrate that MP-LFSR's produce sequences with significantly reduced probability of linear dependence compared to single polynomial LFSR's. We present a general method to determine the probability of encoding as a function of the number of specified bits in the test cube, the length of the LFSR and the number of polynomials. Theoretical analysis and experiments show that the probability of encoding a test cube with s specified bits in an s-stage LFSR with 16 polynomials is 1-10/sup -6/. We then present the new BIT scheme that allows for an efficient encoding of the entire test set. Here the seeds are grouped according to the polynomial they use and an implicit polynomial identification reduces the number of extra bits per seed to one bit. The paper also shows methods of processing the entire test set consisting of test cubes with varied number of specified bits. Experimental results show the tradeoffs between test data storage and test application time while maintaining complete fault coverage. >
439 citations
07 Oct 2002
TL;DR: Embedded deterministic test technology is introduced, which reduces manufacturing test cost by providing one to two orders of magnitude reduction in scan test data volume and scan test time.
Abstract: This paper introduces embedded deterministic test (EDT) technology, which reduces manufacturing test cost by providing one to two orders of magnitude reduction in scan test data volume and scan test time. The EDT architecture, the compression algorithm, design flow, experimental results, and silicon implementation are presented.
430 citations
Cites methods from "LFSR-coded test patterns for scan d..."
...The original idea taking advantage of this phenomenon, known as LFSR-coding, was proposed in [ 11 ] and then refined (under the name of LFSR-...
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...Subsequently, a compressed pattern can be determined by solving the system of equations in a manner similar to techniques presented in [5], [ 11 ], [12], [13], [20]....
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TL;DR: This article summarizes and categories hardware-based test vector compression techniques for scan architectures, which fall broadly into three categories: code-based schemes use data compression codes to encode test cubes; linear-decompression- based schemes decompress the data using only linear operations; and broadcast-scan-based scheme rely on broadcasting the same values to multiple scan chains.
Abstract: Test data compression consists of test vector compression on the input side and response, compaction on the output side This vector compression has been an active area of research This article summarizes and categories these techniques The focus is on hardware-based test vector compression techniques for scan architectures Test vector compression schemes fall broadly into three categories: code-based schemes use data compression codes to encode test cubes; linear-decompression-based schemes decompress the data using only linear operations (that is LFSRs and XOR networks) and broadcast-scan-based schemes rely on broadcasting the same values to multiple scan chains
429 citations