This paper presents a digitally controlled oscillator (DCO) with a novel architecture. The proposed DCO achieves low noise operation without the need for an LC resonator or specialized radio frequency (RF) process layers. Frequency tuning is achieved by controlling capacitive coupled charge injection. The design is easily integrated with digital CMOS circuits and has the flexibility to be scaled to other processes or tuned for specific applications. A proof of concept circuit has been implemented on a 0.13μm CMOS process. The tuning range is from 820 MHz to 1.09 GHz. The phase noise at 1 GHz with an offset frequency of 100 KHz is -92.8 dBc/Hz. The worst case cycle-to-cycle jitter is less than 1.28% with an RMS jitter of 1.7423 ps. Total power consumption is 6.12 mW.

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Keywords Charge injection, Digitally controlled oscillator (DCO), Low noise, Ring oscillator, Switched capacitor
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Conference 2008 IEEE International Symposium on Circuits and Systems, ISCAS 2008
Kuendiger, T. (Till), Chen, F. (Fang), MacEachern, L, & Mahmoud, S.A. (2008). A novel digitally controlled low noise ring oscillator. Presented at the 2008 IEEE International Symposium on Circuits and Systems, ISCAS 2008. doi:10.1109/ISCAS.2008.4541593