A 2.1-mW 0.3V-1.0V wide locking range multiphase DLL using self-estimated SAR algorithm

This paper presents an all-digital multiphase delay-locked loop (ADMDLL) for wide-locking range and micro-power applications. To enhance locking range of the ADMDLL, we proposed the self-estimated successive approximation register-controlled (SESAR) algorithm, which uses the frequency-estimation selector (FES) to avoid harmonic lock issue. In addition, the FES can reuse the delay line to reduce circuit area and power dissipation significantly. By using the stack effect, the proposed leakage-reduced delay unit can save 12% leakage power consumption. After locking, the dynamic frequency monitor window is proposed to compensation phase error caused by PVT variations. The proposed ADMDLL is capable of operating in wide supply voltage range from 0.3V to 1.0V. The power dissipation is only 520μW at 1.25GHz/1.0V, and 2.1 μW at 13MHz/0.3V, respectively. This work is based on UMC 90nm standard CMOS technology.