A Dual-Channel Pipelined ADC With Sub-ADC Based on Flash–SAR Architecture

Abstract

This brief presents a 10-bit dual-channel pipelined flash-successive approximation register (SAR) analog-to-digital converter (ADC) for high-speed applications. The proposed ADC consists of two channels for high operating speed, and each channel adopts a pipelined flash-SAR architecture for low power and a small area. The proposed flash-SAR ADC in the second stage is composed of a 1-bit flash ADC and a 6-bit SAR ADC considering the chip area, operation speed, and circuit complexity. The prototype ADC fabricated in a 45-nm CMOS process occupies 0.16 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The differential and integral nonlinearities of the ADC are less than 0.36 and 0.67 LSB, respectively. The ADC shows a signal-to-noise-and-distortion ratio of 54.6 dB and a spurious-free dynamic range of 64.0 dB with a 78-MHz input at 230 MS/s with a 1.1-V supply. The maximum operating frequency of the ADC is 260 MS/s at a 1.2-V supply. The power consumptions of the ADC with 230 and 260 MS/s are 13.9 and 17.8 mW, respectively.