Gate-leakage compensation scheme for programmable SI-DAC of ΣΔ modulator in deep sub-micron

  • Authors:
  • Yang Xu;Baoyong Chi;Zhihua Wang

  • Affiliations:
  • Institute of Microelectronics, Tsinghua University, Beijing, China;Institute of Microelectronics, Tsinghua University, Beijing, China;Institute of Microelectronics, Tsinghua University, Beijing, China

  • Venue:
  • Analog Integrated Circuits and Signal Processing
  • Year:
  • 2013

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Abstract

A gate-leakage compensation scheme is proposed to solve the gate-leakage current issue caused by large-size current-source transistors in multi-bit switched-current (SI) DACs of the continuous-time ΣΔ modulator in deep sub-micron process without extra power consumption. To cover wide current range due to variable coefficients in different modes, the programmable SI-DAC architecture with 2-bit digital controlled unit cells is proposed. Implemented in 65 nm CMOS, the simulated results verify that the proposed scheme solves the gate-leakage issue and the modulator achieves tremendously high performance of 84.5 dB SQNDR and 94.6 dB SFDR with almost 14 and 19 dB improvement in SQNDR and SFDR, respectively.