AbstractThis paper is concerned with the stability analysis problems of asynchronous sampled‐data systems via an input‐delay approach. Between two sequential sampling times, a sampled‐data system is controlled by previously sampled states and thus can be modeled as a time‐delay system with a saw‐tooth delay. Inevitably, information at the sampling instants have played essential roles in controlling the systems and reducing the conservatism of the stability criteria. Therefore, to further utilize the information at sampling instants, this paper proposes novel looped functionals consisting of integral state variables and their interval‐normalized terms. Three numerical examples including a practical helicopter system demonstrate the effectiveness of the proposed approaches in terms of allowable sampling intervals.