Chitra K. Subramanian

A 4-Mb 0.18-/spl mu/m 1T1MTJ toggle MRAM with balanced three input sensing scheme and locally mirrored unidirectional write drivers

A 4-Mb toggle MRAM, built in 0.18-/spl mu/m five level metal CMOS technology, uses a 1.55 /spl mu/m/sup 2/ bit cell with a single toggling magneto tunnel junction to achieve a chip size of 4.5 mm /spl times/ 6.3 mm. The memory uses unidirectional programming currents controlled by locally mirrored write drivers to apply a robust toggle write sequence. An isolated read architecture driven by a balanced three input current mirror sense amplifier supports 25-ns cycle time asynchronous operation.

A 180 Kbit Embeddable MRAM Memory Module

180 Kbit magnetoresistive random access memory (MRAM) designed for embedding in a 0.28 micron CMOS process has been developed. The memory cell is based on a 1-transistor 1-magnetic tunnel junction (1T1MTJ) bit cell. The architecture, write driver, and sense amplifier are described. The use of a test register to characterize and optimize the memory design is also discussed.