A DLL-based Configurable Multi-Phase Clock Generator for True-Time-Delay Wideband FMCW Phased-Array in 40nm CMOS

In this paper, a delay locked loop (DLL) based configurable multi-phase clock generator with wide operating range and high resolution is proposed. It is implemented by adopting array of configurable DLLs and is able to generate multi-phase frequencies with true-time-delay, which is essential in a wideband FMCW phased array system. Fabricated in a 40nm CMOS process, the proposed multi-phase clock generator achieves configurable phase delay with high resolution of 7ps under varies of reference frequency from 400MHz to 2.5 GHz. The clock generator consumes 20.9mW from a 1.1V supply.

I. Introduction

Due to the stable structure, no jitter accumulation characteristics, and fast locking time, the DLL has been one of the key components in analog signal processing circuits. Most studies of DLL focus on achieving wide operating range, high time resolution, low jitter, fast locking and flexible phase delay [1]–[4]. In addition, highly integrated DLL-based architectures have been widely used for the generation of the on-chip clocks and timing applications, such as reference clock generator, clock and data recovery circuit and frequency synthesizer [5]–[7].