Oscillation-test strategy for analog and mixed-signal integrated circuits

A new low-cost test method for analog integrated circuits, called oscillation-test, is presented. During the test mode, the circuit under test (CUT) is converted to a circuit that oscillates. Faults in the CUT which cause a reasonable deviation of the oscillation frequency from its nominal value can be detected. Using this test method, no test vector is required to be applied. Therefore, the test vector generation problem is eliminated and the test time is very small because a limited number of oscillation frequencies is evaluated for each CUT. Due to its digital nature, the oscillation frequency can be easily interfaced to boundary scan. This characteristics imply that oscillation-test strategy is very attractive for wafer-probe testing as well as final production testing. In this paper, the validity of the proposed test method has been verified throughout some examples such as operational amplifiers and analog-to-digital converter (ADC)