A transfer-curve-folded DCO in 0.13μm CMOS

Abstract

A DCO which achieves fine frequency resolution, provides interface controls for all-digital PLLs, and has a folded transfer curve to avoid frequency discontinuity is presented. The DCO occupies 520 mum times 780 mum, uses 20 mA current and operates from 3.2 GHz to 4.0 GHz. Its phase noise at 400 kHz, 3 MHz and 20 MHz are -117.3, -135.9 and -153.3 dBc/Hz, respectively. Its frequency coverage range and the phase noise satisfy requirements for GSM/GPRS/EDGE applications.