Streamlined design methodology for Cell-Based DCOs

The digitally controlled oscillator (DCO) is a fundamental building block found in many applications. In this work, a design methodology for DCOs is proposed. This methodology focuses on simplicity, reducing the design effort by using only standard digital gates. It achieves so through the use of these gates as varactors in a ring oscillator (RO)-based DCO. The different steps and trade-offs encountered during the application of this methodology are explained in detail. The methodology is tested in a real-use case scenario, resulting in a successful implementation, in a commercial 65nm technology, that meets the required specifications.