A built-in self-test scheme for differential ring oscillators

In this paper a new Built-In Self-Test (BIST) scheme is proposed suitable for testing differential voltage controlled ring oscillators. The proposed testing-scheme is capable of detecting single realistic faults of the circuit under test. These faults can be either short or bridging faults between circuit nodes or open faults at the circuit branches. The test result is provided by a digital Fail/Pass indication signal. Exhaustive simulations have revealed the effectiveness of the proposed technique regarding its fault coverage