A 65-dB-SNDR Pipelined SAR ADC Using PVT-Robust Capacitively Degenerated Dynamic Amplifier

• Published in: IEEE journal of solid-state circuits Vol. 58; no. 4; pp. 961 - 971
• Main Authors: Yoon, Hyunchul, Lee, Changuk, Kim, Taewoong, Kwon, Yigi, Chae, Youngcheol
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amplification; Amplifiers; Analog to digital converters; Analog-digital conversion; Analog-to-digital converter (ADC); capacitive degeneration; capacitively degenerated; Capacitors; dynamic amplifier; High temperature; Linearity; Low voltage; Noise levels; Optimized production technology; pipelined successive-approximation-register (SAR) ADC; Power consumption; process; Registers; residue amplifier; Robustness; SAR; SAR ADC; temperature (PVT) stabilization; Transistors; Voltage; Voltage gain
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2023.3235521

This article presents a process, voltage, and temperature (PVT)-robust capacitively degenerated dynamic amplifier as the residue amplifier of the low-power pipelined successive-approximation-register (SAR) analog-to-digital converter (ADC). The proposed dynamic amplifier achieves a voltage gain of 16 with a two-stage configuration and high linearity over a wide temperature range with an on-chip timing generator. This work solves problems related to the low voltage gain and high temperature-sensitivity of the capacitively degenerated dynamic amplifier, while retaining the advantages of high linearity, wide output swing, and high energy efficiency. The prototype ADC is implemented in a 65-nm CMOS process and achieves 65-dB signal-to-noise-and-distortion ratio (SNDR) and 79.8-dB spurious free dynamic range (SFDR) at a sampling rate of 50 MS/s, while consuming only 0.46 mW. The power overhead of the timing generator is only 10% of the overall power consumption. It shows only 0.7-dB and 1.86-dB SNDR variations at 0.8-1.0-V supply variation and 0 °C-100 °C temperature variation, respectively.