A novel in-memory computing scheme based on toggle spin torque MRAM

This paper proposes a novel in-memory computing (IMC) scheme based on toggle spin torque magnetic random access memory (TST-MRAM), called TST-IMC, which makes full use of the unique TST writing mechanism. In this scheme, all of the computing results are directly written in bit-cells without transferring data out of the memory array. Varied Boolean logic operations, such as, NAND, NOR and XOR, can be achieved by specially configuring decision cells. We can also implement three-input majority logic through replacing a decision cell with a datum cell, which can further be used to realize the carry of full-adder. By using 28 nm CMOS technology node and 50 nmdiameter TST-MRAM, we perform mixed simulations to validate the functionality of the proposed TST-IMC scheme. Simulation results show that XOR logic operation can be carried out within 4 ns at 1.8 V supply voltage while the other basic logic operations can be faster, i.e. within 2 ns. In addition, TST-IMC 33% less time and 44% energy saved comparing with existing IMC schemes.