학술논문

A 10-bit 563-fs Step Constant-Slope Digital-to-Time Converter in 40-nm CMOS With Nonlinearity Cancellation and Range Extension Techniques
Document Type
Periodical
Source
IEEE Transactions on Circuits and Systems I: Regular Papers IEEE Trans. Circuits Syst. I Circuits and Systems I: Regular Papers, IEEE Transactions on. 71(2):526-536 Feb, 2024
Subject
Components, Circuits, Devices and Systems
Linearity
Capacitors
Capacitance
Power demand
Delays
Phase locked loops
Modulation
Capacitor-based digital-to-analog converter (C-DAC)
constant slope
digital-to-time converter (DTC)
femtosecond resolution
INL
phase-locked loop
power-efficient
ultra-low power
Language
ISSN
1549-8328
1558-0806
Abstract
This paper presents a power-efficient constant-slope digital-to-time converter (DTC) with embedded nonlinearity cancellation. By utilizing the capacitor based digital-to-analog converter (C-DAC) to adjust the initial voltage of the discharging process, the DTC achieves a fine resolution of < 600-fs. Sources of nonlinearity are quantitatively analyzed, followed by circuit implementations that intrinsically cancel them. The range-extension technique is proposed to increase the range of the DTC by a factor of two without further complicating the capacitor array. The power consumption of the DTC is reduced by the self-power down technique that automatically detects the end of the conversion and shuts off the current. The proposed DTC consumes 120- $\mu \text{W}$ at 50-MHz clock rate. It achieves a fine resolution of 563-fs over a 10-bit range. The measured differential nonlinearity (DNL) and integral nonlinearity (INL) are 0.14/0.96-LSB, respectively.