A new sensing scheme with high signal margin suitable for Spin-Transfer Torque RAM

Spin-Transfer Torque RAM (STT-RAM)[1] using Tunnel Magneto-Resistance (TMR) devices[2] is one of the most promising "universal memory" implementation because of its high write endurance, low voltage operation and good process-scalability compared to previous nonvolatile memory implementation[3-5]. From a viewpoint of signal sensing circuitry, STT-RAM is very different from conventional RAM, e.g. DRAM, SRAM. In order to achieve high density, high speed and low power required as a universal memory implementation, it is a key issue to develop a sensing scheme that amplifies the read signal from a memory cell at high efficiency. This paper proposes a new sensing scheme with high signal margin, based on a detailed analysis of STT-RAM read operation.