Cyclic-coupled ring oscillators (CCRO) can be used as time-domain quantizers in time-based ADCs and TDCs in order to reach fine time resolution. However, CCROs can oscillate in several oscillation modes. Certain modes may contain in-phase oscillations, which severely degrade the time/phase resolution. This paper presents a method to ensure a design where such modes can not exist, and thus to ensure maximal phase resolution in a CCRO quantizer.