A 20-MHz NDRO thin film memory

The 256-word, 200-bit NDRO memory utilizes magnetic films deposited in arrays of discrete spots on thin glass substrates. Sandwiching of conductors between two substrates provides partial coupling to film pairs. The magnetic films exhibit both uniaxial and biaxial anisotropy and are interrogated by word fields of less than H
k
amplitude. Word currents of 15-ns duration and 5-ns rise time produce sense signals in excess of 1 mV with a 7- to 10-ns duration. A single compact assembly houses the stack and its associated circuitry. Circuits are packaged employing hybrid techniques where electroless plating produces resistors from a nickel-phosphide solution onto copper-clad glass-epoxy laminates.