We propose a new design for testability technique, Parallel Serial Full Scan (PSFS), for reducing the test application time for full scan embedded cores. Test application time reduction is achieved by dividing the scan chain into multiple partitions and shifting in the same vector to each scan chain through a single scan in input. The experimental results for the ISCAS890 circuits showed that PSFS technique significantly reduces both the test application time and the amount of test data for full scan embedded cores.

Reducing test application time for full scan embedded cores

Reducing test application time for full scan embeded cores

A automatic test pattern generator (ATPG) algorithm is proposed that reduces switching activity (between successive test vectors) during test application. The main objective is to permit safe and inexpensive testing of low power circuits and bare die that might otherwise require expensive heat removal equipment for testing at high speeds, Three new cost functions, namely transition controllability, observability, and test generation costs, have been defined. It has been shown, for a fanout free circuit under test, that the transition test generation cost for a fault is the minimum number of transitions required to test a given stuck-at fault. The proposed algorithm has been implemented and the generated tests are compared with those generated by a standard PODEM implementation for the larger ISCAS85 benchmark circuits. The results clearly demonstrate that the tests generated using the proposed ATPG can decrease the average number of (weighted) transitions between successive test vectors by a factor of 2 to 23.

ATPG for heat dissipation minimization during test application

A new ATPG algorithm has been proposed that reduces average heat dissipation (between successive test vectors) during test application. The objective is to permit safe and inexpensive testing of low power circuits and bare dies that would otherwise require expensive heat removal equipment for testing at high speeds. Three new functions, namely transition controllability, observability and test generation costs, have been defined. It has been shown that the transition test generation cost is the minimum number of transitions required to test the corresponding stuck-at fault in fanout free circuits. This cost function is used for target fault selection while the other two functions are used to guide the backtrace and objective selection procedures of PODEM. The tests generated by the proposed ATPG decrease heat dissipation during test application by a factor of 2-23 for benchmark circuits.

In this paper, an efficient technique for test data volume reduction based on the shared scan-in (Illinois Scan) architecture and the scan chain reconfiguration (Dynamic Scan) architecture is defined. The composite architecture is created with analysis that relies on the compatibility relation of scan chains. Topological analysis and compatibility analysis are used to maximize gains in test data volume and test application time. The goal of the proposed synthesis procedure is to test all detectable faults in broadcast test mode using minimum scan-chain configurations. As a result, more aggressive sharing of scan inputs can be applied for test data volume and test application time reduction. The experimental results demonstrate the efficiency of the proposed architecture for real-industrial circuits.

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A reconfigurable shared scan-in architecture

Full scan is a widely accepted design for testability technique for sequential circuits. However, the test application time required by full scan could be high because of the necessity to scan in and scan out test vectors. In this paper, a hybrid scheme is presented that aims to reduce test application time in circuits with full scan. The proposed scheme exploits the inherent sequential nature of the circuit in conjunction with the additional controllability and observability available through full scan. Also, it is shown that the hybrid scheme has an additional advantage of being suited for testing transition faults. >

J. Saxena

Papers

A design for testability scheme to reduce test application time in full scan