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

SUMMARY This paper reports a 65 nm 8 Mb spin transfer torque mag-netoresistance 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 negative-resistance 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.