A 4x folding voltage-to-time converter with adjustable conversion gain and offset for time-based ADC

A folding voltage-to-time converter (VTC) is proposed for time-based ADC. Conventional VTCs suffer serious linearity interference due to its large input range. The proposed VTC adopts a 4x folding architecture, and thus reduce the VTC input range which makes the gain of proposed VTC more larger and linear. The output of a single Voltage-to-Time conversion is -110 ps to +110 ps with the conversion gain of 1.47 ns/V The VTC also realize a process, voltage, and temperature (PVT) robustness by adjust the bias voltage of VTC. This work designed in 65-nm CMOS process achieves a high linearity in a full range of 1.2 Vpp.