Digital low dropout voltage regulators (DLDOs) have been widely applied to emerging edge devices of IoT systems due to the benefit of simply designing, easily integrating to edge devices, and fast responding. Conventional DLDOs insert parallel pMOSs between Vin and Vout, and use a digital controller to turn on appropriate number of pMOSs to obtain required Vout. The turned on pMOSs are suffering from non-negligible Negative-Bias Temperature Instability (NBTI) effect and therefore the power integrity cannot be guaranteed after aging. To mitigate the NBTI effect and to extend the lifetime of DLDOs (as well as the whole circuit), in this paper we propose an improved NBTI-aware DLDO design which uniformly turns on pMOS to avoid bias aging. Experimental results show that with our design, we can achieve 20% DLDO lifetime extension.