Now showing 1 - 2 of 2
  • Publication
    Discrete-time modelling and experimental validation of an All-Digital PLL for clock-generating networks
    In this paper, we derive a mathematical model of an All-Digital Phase-Locked Loop (ADPLL) employing a time-to-digital phase detector. The model we suggest represents a nonlinear discrete-time map and provides significant benefits for the simulation of a single PLL, a network of PLLs or their design. In particular, the model allows us to take into account the jitter of the reference and local clocks and other noises. The mathematical model (the map) is then compared with a behavioural model implemented in MATLAB Simulink and displays identical results. The simulation of the mathematical and behavioural models are further compared with experimental measurements of a 65nm CMOS ADPLL and show a good agreement.
      898Scopus© Citations 11
  • Publication
    Synchronized Interconnected ADPLLs for Distributed Clock Generation in 65 nm CMOS Technology
    This brief presents an active distributed clock generator for manycore systems-on-chip consisting of a 10×10 network of coupled all-digital phase-locked loops, achieving less than 38 ps phase error between neighboring oscillators over a frequency range of 700–840 MHz at VDD=1.1 V. The network is highly robust against VDD variations. An energy cost of 2.7 μW /MHz per node is 7 times lower than that in analog implementations of similar architectures and is twice lower than that in conventional H-tree architectures. This is the largest on-chip all-digital phase-locked loop network ever implemented. With clock generation nodes linked only locally, this solution is proven to be scalable. The presented clock generation network does not require any external reference, except for the start-up frequency selection, generating a synchronized signal in fully autonomous mode and maintaining frequency stability within 0.09% during 1700 seconds. Such a network of frequency and phase synchronized oscillators can be used as a source for local clocking areas.
      283Scopus© Citations 4