Magnetic Shadow RAM

We propose a new shadow RAM circuit, utilizing magnetic tunnel junctions and an independent-double-gate CMOS technology. A shadow RAM combines a conventional static RAM circuit with a non-volatile "shadow", and provides a means to quickly transfer data between them. Non-volatile magnetic storage offers several advantages over current technology for this application, with unlimited write endurance, very fast write time, low power consumption, and improved radiation tolerance. A novel circuit allows the shadow storage to be incorporated into a RAM cell using independent-double- gate transistors. The physical layout of the shadow RAM is unlike bulk MRAM, making it possible to embed the shadow RAM elements into computational logic without the X-Y grid decoding of the cell address. Accordingly, the micromagnetic structures have been optimized for writing with a new "one- wire" technique. We discuss proposed circuits and present circuit simulation results.