A Low-Power 12-Bit 20 MS/s Asynchronously Controlled SAR ADC for WAVE ITS Sensor Based Applications.

Area of Science:

• Electrical Engineering
• Computer Engineering

Background:

• Intelligent Transportation Systems (ITS) and Wireless Access for Vehicular Environments (WAVE) require efficient sensor data acquisition.
• Low-power, high-performance analog-to-digital converters (ADCs) are crucial for these sensor-based applications.
• Existing ADC architectures face challenges in balancing power consumption, speed, and performance.

Purpose of the Study:

• To develop a low-power, high-performance 12-bit successive approximation register (SAR) analog-to-digital converter (ADC).
• To optimize the ADC architecture for reduced power consumption and enhanced performance in WAVE/ITS sensor applications.
• To address power consumption and kick-back issues in critical ADC components.

Main Methods:

• Implementation of a common mode charge recovery (CMCR) switching process for the capacitive digital-to-analog converter (CDAC) to minimize switching energy.
• Design of a mutated dynamic-latch comparator with cascode for high-speed, low-power operation and mitigation of kick-back noise.
• Employment of an asynchronous topology for the logic part to enhance flexibility and performance.
• Fabrication using 65 nm CMOS process technology.

Main Results:

• The proposed CMCR switching technique achieved a 56.3% reduction in switching energy compared to conventional methods.
• The implemented ADC achieved a signal-to-noise distortion ratio (SNDR) of 65.44 dB at Nyquist frequency.
• The device operated at a sampling frequency of 20 MS/s while consuming only 472.2 µW with a 1 V power supply.
• The active area of the fabricated chip was 0.14 mm².

Conclusions:

• The developed asynchronous SAR ADC offers a significant improvement in power efficiency for WAVE/ITS sensor applications.
• The proposed energy-saving switching method and comparator design effectively address key challenges in ADC development.
• This low-power, high-performance ADC is well-suited for resource-constrained intelligent transportation systems.