Patent ID: 6590382
Filing Date: 2003-07-08
Classification: G01R

Abstract:
A test apparatus for testing an integrated circuit that has a scan-based interface by which data can be shifted through a chain of clock storage devices and extracted sequentially therefrom to test the device data storage device's input/output (I/O) signal pins for alternating current (AC) defects comprising:a tester having first and second sets of tester contacts; and an integrated circuit having a set of functional circuits, a scan circuit having an output, a clock circuit having an output and at least three clocked data storage devices arranged in a series; first means for coupling said set of said functional circuits to a respective tester contact in said first set of tester contacts; second means for coupling a respective contact in said first set of tester contacts to said clock circuit, and third means for coupling each respective tester contact in said second set of tester contacts to a selected plurality of said clocked data storage devices; each of said clocked data storage devices being comprised of at least three driver circuits in series; each of said driver circuits in each of said clock data storage devices having a clock input, a scan input and a scan output; the clock input of each of said driver circuits being coupled to the output of said clock circuit; the scan input of the first driver circuit in the first clocked data storage device in said series being coupled to the output of said scan circuit, to the scan output of said first clock data storage device in said series, to the tester and to the scan input of the driver circuit immediately following said first driver circuit in said series; the scan output of each subsequent driver circuit in said series being coupled to the scan input of the following driver circuit in the series; the scan output of the last data driver circuit in said series being coupled to the tester and to the next data storage device in said series; the scan output of each subsequent data storage device in said series being coupled to the tester and to the scan input of the following data storage device in the series; and the scan output of the last data storage device in said clocked data storage device being coupled to the tester.