Common mode capacitive cross coupling in memory arrays

Capacitance between intersecting word and bit lines of a memory array causes a special type of line-to-line interaction. Signal waveforms may be seriously distorted if a large number of common polarity signals occur simultaneously and the word and bit line delay times are comparable to the width of the signal. A 2- dimensional linear array model with distributed parameters was used, and a mathematical process for the determination of the wave coefficients according to the partial differential equation of the array and its boundary conditions is described. Typical cases were computed, interpreted, and compared to simple approximations which are useful as rules of thumb for the memory designer.