Abstract
To bring Spin Wave (SW) based computing paradigm into practice and
develop ultra low power Magnonic circuits and computation platforms, one
needs basic logic gates that operate and can be cascaded within the SW
domain without requiring back and forth conversion between the SW and
voltage domains. To achieve this, SW gates have to possess intrinsic
fanout capabilities, be input-output data representation coherent, and
reconfigurable. In this paper, we address the first and the last
requirements and propose a novel 4-output programmable SW logic. First,
we introduce the gate structure and demonstrate that, by adjusting the
gate output detection method, it can parallelly evaluate any 4-element
subset of the 2-input Boolean function set AND, NAND, OR, NOR, XOR, and
XNOR. Furthermore, we adjust the structure such that all its 4 outputs
produce SWs with the same energy and demonstrate that it can evaluate
Boolean function sets while providing fanout capabilities ranging from 1
to 4. We validate our approach by instantiating and simulating different
gate configurations such as 4-output AND/OR, 4-output XOR/XNOR, output
energy balanced 4-output AND/OR, and output energy balanced 4-output
XOR/XNOR by means of Object Oriented Micromagnetic Framework (OOMMF)
simulations. Finally, we evaluate the performance of our proposal in
terms of delay and energy consumption and compare it against existing
state-of-the-art SW and 16nm CMOS counterparts. The results indicate
that for the same functionality, our approach provides 3x and 16x energy
reduction, when compared with conventional SW and 16nm CMOS
implementations, respectively.