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A large capacitive load amplifier with enhanced active-feedback frequency compensation is proposed in this paper. The enhancement is achieved through using a wide-bandwidth scalar circuit to increase the transconductance of the output stage so that the overall bandwidth of the amplifier can be extended considerably. Implemented in a standard CMOS 130-nm technology, with a supply of 0.7 V and consuming 27 μA of current, the amplifier drives a load capacitor of 15 nF. No on-chip resistor is needed; only a 0.91-pF compensation capacitor is used to maintain stability. The achieved gain-bandwidth product and phase margin are 1.28 MHz and 66.9°, respectively. Moreover, the slew rate is 0.263 V/μs. The active chip area is 0.0056 mm2. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A dominant-pole substitution (DPS) technique for low-dropout regulator (LDO) is proposed in this paper. The DPS technique involves signal-current feedforward and amplification such that an ultralow-frequency zero is generated to cancel the dominant pole of LDO, while a higher frequency pole substitutes in and becomes the new dominant pole. With DPS, the loop bandwidth of the proposed LDO can be significantly extended, while a standard value and large output capacitor for transient purpose can still be used. The resultant LDO benefits from both the fast response time due to the wide loop bandwidth and the large charge reservoir from the output capacitor to achieve the significant enhancement in the dynamic performances. Implemented with a commercial 0.18-μm CMOS technology, the proposed LDO with DPS is validated to be capable of delivering 100 mA at 1.0-V output from a 1.2-V supply, with current efficiency of 99.86%. Experimental results also show that the error voltage at the output undergoing 100 mA of load transient in 10-ns edge time is about 25 mV. Line transient responses reveal that no more than 20-mV instantaneous changes at the output when the supply voltage swings between 1.2 and 1.8 V in 100 ns. The power-supply rejection ratio at 3 MHz is −47 dB. [ABSTRACT FROM AUTHOR]