Ferrite device characteristics and coincident current store performance

A shmoo plot or failure boundary curve for a coincident current store is a region defining the limits of drive current, both address and bit, within which the system can operate satisfactorily. Because of the nonlinear characteristics of the ferrite core, the sense circuitry, and many aspects of the drive system, the exact mathematical expression of a shmoo curve would be quite involved, and therefore is treated empirically. The effect on storage operation of nonuniformity in device properties, such as squareness and threshold, is explored. Based on distributions of certain device properties which can be related to the output parameters of a core measured under conventionally accepted 3D test conditions, constant shmoo curves are derived.