Testing content addressable memories with physical fault models  

作　　者：马麟 杨旭 钟石强 陈云霁 

机构地区：[1]Institute of Computing Technology,Chinese Academy of Sciences [2]Graduate University of the Chinese Academy of Sciences

出　　处：《Journal of Semiconductors》2009年第8期109-115,共7页半导体学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No.60603049);the National High Technology Research and Development Program of China (Nos.2008AA110901,2007AA01Z112,2009AA01Z125);the State Key Development Program for Basic Research of China (No.2005CB321600);the Beijing Natural Science Foundation (No.4072024)

摘　　要：Content addressable memory （CAM） is widely used and its tests mostly use functional fault models. However, functional fault models cannot describe some physical faults exactly. This paper introduces physical fault models for write-only CAM. Two test algorithms which can cover 100% targeted physical faults are also proposed. The algorithm for a CAM module with N-bit match output signal needs only 2N＋2L＋4 comparison operations and 5N writing operations, where N is the number of words and L is the word length. The algorithm for a HIT-signal-only CAM module uses 2N＋2L＋5 comparison operations and 8N writing operations. Compared to previous work, the proposed algorithms can test more physical faults with a few more operations. An experiment on a test chip shows the effectiveness and efficiency of the proposed physical fault models and algorithms.Content addressable memory （CAM） is widely used and its tests mostly use functional fault models. However, functional fault models cannot describe some physical faults exactly. This paper introduces physical fault models for write-only CAM. Two test algorithms which can cover 100% targeted physical faults are also proposed. The algorithm for a CAM module with N-bit match output signal needs only 2N＋2L＋4 comparison operations and 5N writing operations, where N is the number of words and L is the word length. The algorithm for a HIT-signal-only CAM module uses 2N＋2L＋5 comparison operations and 8N writing operations. Compared to previous work, the proposed algorithms can test more physical faults with a few more operations. An experiment on a test chip shows the effectiveness and efficiency of the proposed physical fault models and algorithms.

关 键 词：content addressable memory test algorithm physical fault model 

分 类 号：TP333[自动化与计算机技术—计算机系统结构] TP302.8[自动化与计算机技术—计算机科学与技术]