A Low-Power Class-AB Gm-Based Amplifier With Application to an 11-bit Pipelined ADC

• Published in: IEEE transactions on very large scale integration (VLSI) systems 2016-07, Vol.24 (7), p.2562-2569
• Main Authors: Suh, Yunjae, Choi, Seungnam, Sim, Jae-Yoon
• Format: Article
• Language: English
• Subjects: Amplification; Analog-to-digital converter (ADC); Bias; Calibration; common-mode current suppression; Consumption; Digital switching; Direct current; Electric potential; Figure of merit; Gain; Gm-based amplifier; High gain; Logic gates; operational transconductance amplifier; pipelined ADC; Receivers & amplifiers; Resistance; Resistors; self-biased cascode configuration; Transistors; variable resistor; Very large scale integration
• ISSN: 1063-8210; 1557-9999
• DOI: 10.1109/TVLSI.2015.2504494

A Gm-based amplifier is proposed for the use in low-voltage and low-power switched-capacitor circuits. At the input stage of the amplifier, a common-mode current-suppression scheme effectively suppresses the common-mode current with the differential-mode current even amplified, resulting in decrease in dc power consumption. At the output stage of the amplifier, a self-biased cascode configuration adaptively changes bias voltages to achieve both the cascode operation for high gain and digital switching operation for fast transients. The proposed amplifier is applied to a design of an 11-bit pipelined ADC with a 0.13-μm CMOS process. The implemented analog-to-digital converter consumes 80 μW from a single 0.7 V supply at 2.5 MS/s. It achieves an effective number of bit of 9.72 bit without any calibration scheme and a figure of merit of 37.8 fJ/c-s at near Nyquist rate.