Statistical design techniques for high-speed circuit boards with correlated structure distributions

New statistical design techniques have been developed for the line structures of high-speed circuit boards. These techniques account for dimensional distribution correlations caused by the fabrication process. Monte Carlo simulation is introduced into the finite-element method for calculating line parameters. The eye-pattern at the receiving end of transmission lines with parallel and stub parts is simulated, using distributed circuit models, for the calculated line parameter distributions. The simulator has an algorithm to save computer time. The calculated and experimental results are compared, and the accuracy of the simulation is discussed. Calculation results imply that the evaluation for the dimensional distribution of fabrication processes is very important. The timing and amplitude margins are found to depend strongly on fabrication deviations.<
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