A 124-dB double-gain-boosted cascode amplifier with 92% rail-to-rail output swing

A CMOS amplifier with 124-dB dc gain and 92% rail-to-rail output swing is proposed in this paper. The proposed amplifier uses double gain-boosting technique, enabling triode-region operation in cascode output stage. The design is fabricated in a commercial 0.35-μm CMOS technology. The active chip area is 84 μm × 170 μm. Experimental results show that with the supplies of ±1 V, the high-gain region is extended beyond -0.93 V and 0.91 V. The unity-gain frequency is about 300 kHz with a phase margin of 65° when driving a loading capacitor of 100 pF. Signal distortion is significant reduced compared to the conventional design due to extension of the high-gain region in the proposed amplifier.