A 3.2 GHz Injection-Locked Ring Oscillator-Based Phase-Locked-Loop for Clock Recovery

An injection-locked ring oscillator-based phase-locked-loop targeting clock recovery for space application at 3.2 GHz is presented here. Most clock recovery circuits need a very low phase noise and jitter performance and are thus based on LC-type oscillators. These excellent performances come at the expense of a very poor integration density. To alleviate this issue, this work introduces an injection-locked ring oscillator-based PLL circuit. The combination of the injection-locking process with the use of ring oscillators allows for the benefit of excellent jitter performance while presenting an extremely low surface area due to an architecture without any inductor. The injection locking principle is addressed, and evidence of its phase noise and jitter improvements are confirmed through measurement results. Indeed, phase noise and jitter enhancements up to 43 dB and 23.3 mUI, respectively, were measured. As intended, this work shows the best integration density compared to recent similar state-of-the-art studies. The whole architecture measures 0.1 mm2 while consuming 34.6 mW in a low-cost 180 nm CMOS technology