Ultra-low-power fully-integrated voltage regulators with fast load-transient performance are highly attractive for low-power systems-on-a-chip (SoCs). In such systems, the digital units working in the subthreshold region are more sensitive to supply variations. The digital low-dropout regulator (DLDO) is more suitable for low-supply-voltage operation, as compared to an analog LDO regulator. But, traditional DLDOs are either slow or power hungry, and need a large output capacitor (consumes area) to survive a fast load transient. When a higher clock frequency is used for faster response, both the current efficiency and the loop stability are degraded [1]. An analog-assisted (AA) loop was used in [2] to provide a high-pass loop in parallel with the slow digital loop for fast response. However, a large coupling capacitor (100pF) was still needed, trading off area with power and speed. An NMOS power stage as a source follower is sometimes used in replica LDOs and cascaded LDOs [3] for its intrinsic response to load transient; the NMOS source follower naturally provides more output current when VOUTdrops. To improve upon the power-speed-area tradeoffs, this paper presents a DLDO using NMOS power switches, and employs a NAND-gate-based high-pass analog path (NAP) to assist the slow low-power digital loop. With these two techniques, nearly two orders of better FoM is achieved relative to the state-of-the-art. © 2018 IEEE.