A 200MS/s, 8-bit Time-based Analog to Digital Converter (TADC) in 65nm CMOS technology

Abstract

Time-based-Analog-to-Digital-Converter (TADC) is an important block in various applications that require higher resolution and lower power consumption compared to the conventional ADCs at scaled CMOS technologies. In time-based ADCs, the input voltage is first converted into a pulse in time by using a Voltage-to-Time Converter (VTC) circuit, and then the pulse is converted to a digital output by using a Time-to-Digital Converter (TDC) circuit. In this paper, a TADC is proposed with a VTC that achieves high linearity and large dynamic input range and a TDC that achieves a time resolution of 3.9 ps. A 200MS/S, 8-bit TADC with effective number of bits (ENOB) equals 7.6 bits is proposed.