Scan flip-flops with on-line testing ability with respect to input delay and crosstalk faults

Abstract

We propose a possible modification to the internal structure of scan flip-flops, which allows the online detection of delay and crosstalk faults affecting their input. Our solution allows to obtain, together with the flip-flop output datum, an indication denoting whether or not the provided datum is incorrect, because of an input crosstalk or delay fault. The proposed solution features self-checking ability with respect to a wide set of possible internal faults, including node stuck-ats, transistor stuck-ons and stuck-opens, resistive bridgings, delays, transient and crosstalk faults.