基于BIST的SRAM型FPGA故障测试

从生产者角度对FPGA芯片测试技术进行深入而全面的研究,是保证制造出高可靠性芯片的一个重要前提。由于FPGA具有可重复编程性,该方法通过编程将FPGA内部资源划分为多个内建自测试（BIST,built in self test）模块,然后多次配置改换每个BIST模块中各个组成部分的角色和测试路径,进而达到对FPGA内部资源完全测试的目的。由于给出的方法是将内部资源作为一个整体来测试,所以FPGA的可编程逻辑资源和互连资源的测试问题可同时进行,继而有效地减少编程难度和测试时间。最后的实验结果表明该方法的有效性。     

A Built-In Self-Test structure for measuring gain and 1-dB compression point of Power Amplifier

This paper proposes a Built-In Self-Test (BIST) structure for measuring the gain and the 1-dB compression point of the Power Amplifier (PA) in transceiver ICs. In this structure, it is not necessary to use the external devices for mapping and DC measuring because of linearity of blocks, comparative performance in the linear region and the digital representation of the 1-dB compression point and gain value. The BIST Circuit is designed and simulated in 180 nm RF-CMOS process with Spectre-RF for a 900 MHz PA while it can achieve an acceptable accuracy which the input referred 1-dB compression point and gain value can be obtained with an error of about 0.2 dBm and 0.18 dB, respectively and the testing time is about 25 µs depends on resolution. Finally, in order to verify the proposed approach, we implemented practically a similar discrete circuit as proof-of-concept prototype that it obtained input referred 1-dB compression point value with an error of about 0.15 dBm.     

可重构硬件内建自测试与容错机制研究

传统可重构硬件自测试方法复杂,容错时资源利用率低,且往往需要额外的软件配合处理器来实现.为此,设计了一种具有自测试与自主容错能力的新型可重构硬件结构.对于故障自测试,提出了能在线执行的自主循环测试方法;对于硬件容错,提出了分层自主容错机制:在功能细胞单元内测试到逻辑故障时,先用功能细胞单元内部的空闲基本逻辑单元替代故障基本逻辑单元;当没有空闲基本逻辑单元时,则将整个故障功能细胞单元的功能重配置到距其最近的空闲功能细胞单元中,实现两层容错.以6×6并行乘法器为例,验证了新型可重构阵列能够降低容错时间复杂度并提高冗余资源利用率.     

一种多核共享测试数据的BIST方案

文中提出了一种新颍的SOC芯片BIST方案。该方案是利用相容技术和折叠技术,将SOC芯片中多个芯核的测试数据整体优化压缩和生成,并且能够实现多个芯核的并行测试,具有很高的压缩率,平均压缩率在94%以上;且结构简单、解压方便、硬件开销低,实验证明是一种非常好的SOC芯片的BIST方案。     

应用向量划分的低功耗确定性BIST方法

提出一种能够与LFSR重播种技术结合的确定性向量生成方法,该方法利用扫描向量中的切片重叠来同时减少确定位数目和跳变数目,可大大降低测试功耗和测试存储.在硬件结构中,用一个译码器来生成控制信号.实验结果表明,对于ISCAS89基准电路,采用文中方法能够减少80%左右的跳变,而只需要原始Mintest测试集25%左右的测试数据存储.     

一种新的低功耗内建自测法 􀀂 􀀂 􀀂 线性反馈移位寄存器结构的更改

本文提出了一种通过改变线性反馈移位寄存器（LFSR）的结构实现低功耗内建自测试方法。在伪随机测试方式下，随着测试的进行，测试矢量的效率大幅降低。通过改变线性反馈移位寄存器的结构滤掉无效的测试矢量从而实现低功耗测试。实践证明，改变线性反馈称位寄存器的结构的方法是有效的并且对故障覆盖率没有影响。     

数字IP芯核的多特征比较内建自测试方法

由于不确知那些不属于IP芯核测试集的测试矢量的无故障响应,造成在伪随机测试下测试者无法获取被测IP芯核的无故障特征,上述事实构成了测试数字IP芯核的挑战之一。基于多特征检验原理,研究了适用于数字IP芯核的内建自测试（BIST）实现方法——MSCBIST。分析了多特征比较的故障混叠概率,并给出了其近似值。通过执行芯片上的多特征检查,显著降低了故障的潜隐性。MSCBIST无需存储多个无故障特征,支持并行的测试和特征检查,可以显著减少功能测试中的测试时间和降低故障混叠的概率。MSCBIST既可以用于确定性测试,也可以用于伪随机测试。     

板级SRAM的内建自测试(BIST)设计

板级SRAM的内建自测试的设计,是为了确保板级SRAM的可靠性。考虑到板级SRAM各种故障模型,选择使用MarchC-SOF算法,其对呆滞故障、跳变故障、开路故障、地址译码器故障和字节间组合故障有100%的故障覆盖率,优化面向"字节"的MarchC-SOF算法和扩展延时元素后,算法可对SRAM进行字节内组合故障和数据维持力故障测试。同时在只增加少量成本的情况下,使用FPGA构成存储器的BIST控制器,可以满足SRAM的可测性的要求。     

用于k测试的BIST测试向量生成器

检测CMOS电路中的开路故障通常需要使用测试向量对。内建自测试(BIST)作为一种有效的测试技术可以大大降低测试开销。本文采用一种具有规则性、模块化和层叠结构的自动控制单元(CA)，来构造产生测试向量对的BIST模块。实验证明，该方法用于瞬态电流测试是有效的。     

RF calibration of on-chip DfT chain by DC stimuli and statistical multivariate regression technique

The problem of parameter variability in RF and analog circuits is escalating with CMOS scaling. Consequently every RF chip produced in nano-meter CMOS technologies needs to be tested. On-chip Design for Testability (DfT) features, which are meant to reduce test time and cost also suffer from parameter variability. Therefore, RF calibration of all on-chip test structures is mandatory. In this paper, Artificial Neural Networks (ANN) are employed as a multivariate regression technique to architect a RF calibration scheme for DfT chain using DC- instead of RF (GHz) stimuli. The use of DC stimuli relaxes the package design and on-chip routing that results in test cost reduction. A DfT circuit (RF detector, Test-ADC, Test-DAC and multiplexers) designed in 65 nm CMOS is used to demonstrate the proposed calibration scheme. The simulation results show that the cumulative variation in a DfT circuit due to process and mismatch can be estimated and successfully calibrated, i.e. 25% error due to process variation in DfT circuit can be reduced to 2.5% provided the input test stimuli is large in magnitude. This reduction in error makes parametric tests feasible to classify the bad and good dies especially before expensive RF packaging.