A high slew-rate amplifier with push-pull output driving capability is proposed to enable an ultra-low quiescent current ( 1 A) low-dropout (LDO) regulator with improved transient responses. The proposed amplifier eliminates the tradeoff between small and large slew-rate that is imposed by the tail-current in conventional amplifier design. Push-pull output stage is introduced to enhance the output driving ability. Small dropout voltage ( DO ) with large-size pass transistor and ultra-low can thus be used to minimize power loss of LDO regulator without transient-response degradation. The proposed amplifier helps to improve stability of LDO regulators without using any on-chip and off-chip compensation capacitors. This is beneficial to chip-level power management requiring high-area efficiency. An LDO regulator with the proposed amplifier has been implemented in a 0.18-m standard CMOS process and occupies 0.09 mm 2 . The LDO regulator can deliver 50-mA load current at 1-V input and 100-mV DO . It only consumes 1.2 A and is able to recover within 4 s even under the worst case scenario.Index Terms-High slew rate, low-dropout (LDO) regulator, low-quiescent current, tail current.

MoS2 and other atomic-level thick layered materials have been shown to have a high potential for outperforming Si transistors at the scaling limit. In this work, we demonstrate a MoS2 transistor with a low voltage and high ON/OFF ratio. A record small equivalent oxide thickness of ∼1.1 nm has been obtained by using ultra high-k gate dielectric Pb(Zr0.52Ti0.48)O3. The low threshold voltage (<0.5 V) is comparable to that of the liquid/gel gated MoS2 transistor. The small sub-threshold swing of 85.9 mV dec(-1), the high ON/OFF ratio of ∼10(8) and the negligible hysteresis ensure a high performance of the MoS2 transistor operating at 1 V. The extracted field-effect mobility of 1-10 cm(2) V(-1) s(-1) suggests a high crystalline quality of the CVD-grown MoS2 flakes. The combination of the two-dimensional layered semiconductor and the ultra high-k dielectric may enable the development of low-power electronic applications.