摘要

This brief presents a two-step hybrid integrator (TSHI) that can operate at a wide supply voltage range, which is demonstrated with a third-order Delta Sigma analog-to-digital converter (ADC). The proposed TSHI consists of a zero-crossing-detector (ZCD)-based integrator and an inverter-based integrator. In the coarse-integration step, the ZCD-based integrator performs a fast integration without concern for overshoot or detection delay issues. In the fine-integration step, the inverter-based integrator performs the residual integration with high accuracy. Hence, the TSHI provides fast and accurate integration process. In addition, the TSHI supports trade-off between voltage-scalable bandwidth and power consumption for an energy efficient operation of Internet-of-Things sensor nodes, owing to the scalable operation of the ZCD and inverter. The proposed Delta Sigma ADC is fabricated in a 65-nm LP CMOS process, and the active area is 0.38 mm(2). The fabricated ADC operates at supply voltages from 0.4 to 1 V. Depending on the supply voltage and sampling frequency, the power consumption and bandwidth of the ADC can be scaled from 12.7 to 948 mu W and from 7.5 to 400 kHz, respectively. The ADC maintains an SNDR higher than 60 dB within the operating supply range.

  • 出版日期2017-12