Testing analog and mixed-signal integrated circuits using oscillation-test method

TLDR

The paper proposes a low‑cost oscillation test method for analog integrated circuits. The method converts the circuit under test into an oscillator, detects faults by observing frequency deviations from a tolerance band, eliminates test vector generation, and evaluates the output frequency digitally for rapid testing. Simulations and practical tests on op‑amps, amplifiers, filters, and ADCs confirm the method’s high fault coverage and suitability for wafer‑probe and production testing.

Abstract

A new low-cost test method for analog integrated circuits, called the 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 deviate the oscillation frequency from its tolerance band 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 only a single output frequency is evaluated for each CUT. The oscillation frequency may be considered as a digital signal and therefore can be evaluated using pure digital circuitry. These characteristics imply that the oscillation-test strategy is very attractive for wafer-probe testing as well as final production testing. In this note, the validity of the proposed test method has been verified throughout various examples such as operational amplifiers, amplifiers, filters, and analog-to-digital converters (ADCs). The simulations and practical implementation results affirm that the presented method assures a high fault coverage.