An 8-phase 10GHz voltage controlled ring oscillator for 40 Gbit/s BiPON clock-and-data recovery

New technologies such as cloud services and the Internet of Things have led to a demand for higher bandwidths, as well as the need for dynamic bandwidth allocation. This flexible bandwidth is offered by the BiPON protocol. By using BiPON, a significant power consumption reduction can be realized at the receiver side by using a 1:4 sub-sampling clock-and-data recovery circuit (CDR). To realize this CDR, the phase detector needs 8 phases of a 10GHz sampling clock. In this paper, we present the design and measurements of such a VCO, which has a tuning range of 6.57 GHz to 10.61 GHz and a gain of 250 MHz/V, while consuming about 30mW.