Test Margin and Yield in Bundled Data and Ring-Oscillator Based Designs

Both ring-oscillator based clocks and bundled-data designs mitigate the ill effects of process, voltage, and temperature (PVT) variations. They both rely on delay lines which, when made post-silicon tunable, offer the opportunity to add test margin into the design in which the delay line in shipped products is set slower than that which is successfully tested. This paper mathematically analyzes the resulting yield and shipped product quality loss and compares them to traditional synchronous design, quantifying the potential benefits that arise from the correlation in delay among paths in the delay line and combinational logic.