A digitally programmable ring oscillator in the UWB range

The increasing interest in impulse radio UWB communication links focuses the research interest on building blocks optimized for these specific systems. In this context, this paper proposes a ring oscillator for an impulse radio UWB transmitter. A multiloop ring oscillator is considered because it holds the potential of both high oscillation frequency and fast switch-on time. The novelty of the proposed inverter cell is found in the possibility to adjust the oscillation frequency digitally, rather than with an analog voltage. This leads to larger tuning range and less sensitivity to control noise. The digitally controlled oscillator is designed in 0.13μm CMOS technology and according to simulations the tuning range is from 4 GHz to 12.5 GHz. The power consumption is below 8 mW.