STT-MRAM Operating at 0.38V Using Negative-Resistance Sense Amplifier

This paper reports a 65 nm 8 Mb spin transfer torque magnetoresistance random access memory (STT-MRAM) operating at a single supply voltage with a process-variation-tolerant sense amplifier. The proposed sense amplifier comprises a boosted-gate nMOS and negativeresistance pMOSs as loads, which maximizes the readout margin at any process corner. The STT-MRAM achieves a cycle time of 1.9 μs (= 0.526 MHz) at 0.38 V. The operating power is 1.70 μW at this voltage. The minimum energy per access is 1.12 pJ/bit when the supply voltage is 0.44 V. The proposed STT-MRAM operates at a lower energy than an SRAM when the utilization of the memory bandwidth is 14% or less. key words: STT-MRAM, low-voltage, process-variation-tolerant

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