Testing techniques for VLSI circuits are undergoing many exciting changes. The predominant
method for testing digital circuits consists of applying a set of input stimuli to the IC and
monitoring the logic levels at primary outputs. If for one or more inputs there is a
discrepancy between the observed output and the expected output then the IC is declared to be
defective. A new approach to testing digital circuits which has come to be known as IDDQ
testing has been actively researched for the last fifteen years. In IDDQ testing the steady
state supply current rather than the logic levels at the primary outputs is monitored. Years
of research suggests that IDDQ testing can significantly improve the quality and reliability of
fabricated circuits. This has prompted many semiconductor manufacturers to adopt this testing
technique among them Philips Semiconductors Ford Microelectronics Intel Texas Instruments
LSI Logic Hewlett-Packard SUN microsystems Alcatel and SGS Thomson. This increase in the
use of IDDQ testing should be of interest to three groups of individuals associated with the IC
business: Product Managers and Test Engineers CAD Tool Vendors and Circuit Designers.
Introduction to IDDQ Testing is designed to educate this community. The authors have summarized
in one volume the main findings of more than fifteen years of research in this area.
