Journal of Xidian University

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1.5bit substage circuit for charge domain pipelined ADCs

HUANG Songren1;CHEN Zhenhai1,2;ZHANG Hong3;LI Xue3;QIAN Hongwen2;YU Zongguang1,2   

  1. (1. School of Microelectronics, Xidian Univ., Xi'an 710071, China;
    2. No.58 Research Institute, China Electronic Technology Group Corporation, Wuxi 214035, China;
    3. School of Electronics and Information Engineering, Xi'an Jiaotong Univ., Xi'an 710049, China)
  • Received:2015-05-06 Online:2016-12-20 Published:2017-01-19

Abstract:

A 1.5bit sub-stage circuit based on bucket-brigade devices (BBD) for high speed charge domain pipelined ADCs is presented to solve the problem that the performances of high-speed, high-resolution ADCs rely on the opamps with large gain-bandwidth production, which results in large power consumption. Charge transfer and residue charge calculation are realized with a boosted charge transfer (BCT) circuit in the proposed 1.5bit sub-stage, and therefore, the high-performance opamps in traditional pipelined ADCs are eliminated and the power consumption can be reduced remarkably. Based on the proposed 1.5bit sub-stage circuit, a 10bit 250MS/s charge domain pipelined ADC is designed in 0.18μm CMOS technology. Measurement results under a sampling frequency of 250MHz and an input sinusoidal frequency of 9.9MHz show that the ADC achieves a spurious free dynamic range (SFDR) of 64.4dB and a signal-to-noise-and-distortion ration(SNDR) of 56.9dB, with power consumption of only 45mW.

Key words: pipelined analog-to-digital converter, pipelined sub-stage circuit, charge domain