An Analysis of the Relationship between IDDQ Testability and D-Type Flip-Flop Structure

Yukiya MIURA  Hiroshi YAMAZAKI  

IEICE TRANSACTIONS on Information and Systems   Vol.E81-D   No.10   pp.1072-1078
Publication Date: 1998/10/25
Online ISSN: 
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Fault Tolerant Computing
IDDQ testing,  bridging faults,  flip-flops,  fault analysis,  

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This paper describes IDDQ testability for bridging faults in a variety of flip-flops. The flip-flop is a basic element of the sequential circuit and there are various structures even for the same type. In this paper, we use five kinds of master-slave D-type flip-flops as the circuit under test. Target faults are two-line resistive bridging faults extracted from a circuit layout. A flip-flop with a deliberately introduced bridging fault is simulated by the SPICE simulator. Simulation results show that IDDQ testing cannot detect faults existing at specific points in some flip-flops, and this problem depends on the flip-flop structure. However, IDDQ testing has high fault coverage ( 98%) compared with traditional logic testing. We also examine performances of fully IDDQ testable flip-flops.