Analytic Method of Fast Eye-Diagram Index for Multiple Coupled Lines in DDR

Double data rate (DDR) memory interface is used in an increasing number of electronic products to increase the efficiency of memory access. Factors such as signal propagation delay, reflection, and crosstalk need to be considered for signal integrity design. This study derives the transfer function of a single transmission line under mismatched boundary conditions and extends it to multiple coupled transmission lines. By utilizing inverse Fourier transform, the pulse responses are obtained and, based on peak distortion analysis, the worst-case eye height and eye width are quickly extracted, saving time in the simulation and achieving high accuracy for the design of high-speed DDR memory interface.