A scalable high-linearity two-step DTC-assisted voltage-to-time converter with rail-to-rail input-range for time-based circuits

This paper presents a highly digital voltage-to-time converter (VTC), which is compatible with advances in CMOS scaling and ability of operating under low supply voltages. The proposed design utilizes coarse-fine structure which operates at rail-to-rail input range with high linearity, as well as making it possible to increase the gain conversion and output delay range of VTC up to a desired value. The inverter-based implementation of the proposed VTC makes it suitable for time-based circuits which use digital-like circuits to perform time-mode signal processing (TMSP). The presented VTC is designed and simulated in TSMC 90-nm CMOS technology at supply voltage of 1 V, which shows a conversion gain of 5 ns/V, and the output delay range is as high as 5000 ps. With a 33.3 MHz sampling frequency, the VTC exhibits a signal-to-noise-and distortion ratio (SNDR) of 56 dB, while the power consumption is 210 mu W.