Texas Instruments Corporation

Alvis D Stephenson, Jr

James Thomas Carlo

Rex Alan Naden

Gene D Lee

Hsiao-Yuan Li

A magnetic bubble domain package in which a magnetic bubble domain chip is bonded to conductors disposed on a thin film interconnect member which is formed to allow a reduction in the volume of the drive coils of the package. The conductors of the interconnect member are bonded to a lead frame which provides signal leads for the magnetic bubble domain chip and the drive coils. The interconnect member with magnetic bubble domain chip and lead frame bonded thereto is encapsulated with a molding compound, the chip being located precisely within the mold in order to insure placement of the chip in the geometric center of the drive coils. The drive coils are prewound and slipped onto the premolded package through slots formed during the molding process to reduce the volume of the coils, and the coils terminated directly onto the signal leads of the lead frame. This chip substructure is supplied with the magnetic field prependicular to the planar surface of the chip by means of a bias field structure formed by permanent magnets secured within an open ended tubular housing which acts as a shield to shunt stray magnetic fields in the external operating environment of the device. A second molding operation encapsulates the chip substructure within the bias field structure to complete the package.

Single chip molded magnetic bubble memory package

Method and apparatus for testing and setting the field strength of permanent magnets in a magnetic bubble domain chip module, wherein the final molded module is formed to contain a pair of longitudinal slots which run through the module on opposite sides thereof. The module is inserted, via said slots, onto conducting members of a magnetic bubble module testing apparatus. The conducting members effectively provide one turn coils on each side of the module. Current is induced in these coils in such a way as to either add to or subtract from the bias field provided for the magnetic bubble domain chip by the permanent magnets of the module. The module is tested to determine the upper and lower operating levels of the bias field for effective operation of the chip, and the device is remagnetized to set the bias field of the module in the center, or optimal point, of the bias margin.

Method and apparatus for testing and setting magnetic field strength of

A magnetic bubble domain package suitable for single or multiple chips in which the coil assembly for producing the rotating magnetic field necessary for bubble movement and logical operations to be performed on these chips comprises a pair of coils wound on a magnetic body in orthogonal relationship with respect to each other which is located external to said chip or chips in order to reduce coil size and power requirements. The package employs an open bias field magnet assembly which comprises an open-ended tubular housing constructed of shielding material and having permanent magnets mounted therein with soft magnetic plates disposed on the permanent magnets. An alternate embodiment employs only a single permanent magnet and a single soft magnetic plate secured within the tubular housing, and uses the magnetic body of the coil assembly as part of the bias field assembly. The chip substructure which is served by this bias field assembly employs a metal plate as an image current producer to increase the uniformity of the drive field. An interconnect member constructed of a thin film of insulating material with electrical conductors disposed thereon is used to provide the interface between the external signal leads of the package and the magnetic bubble domain chip.

Growing community of inventors

Dallas, TX, United States of America

Alvis D Stephenson, Jr