Mixed-Signal Vector-by-Matrix Multiplier Circuits Based on 3D-NAND Memories for Neurocomputing
Mohammad Bavandpoura, Shubham Sahayb, Mohammad Reza Mahmoodic and Dmitri Strukovd
ECE Department, UC Santa Barbara, Santa Barbara, USA
ambavandpour@ece.ucb.edu
bshubhamsahay@ece.ucb.edu
cmrmahmoodi@ece.ucb.edu
dstrukov@ece.ucb.edu
ABSTRACT
We propose an extremely dense, energy-efficient mixed-signal vector-by-matrix-multiplication (VMM) circuits based on the existing 3D-NAND flash memory blocks, without any need for their modification. Such compatibility is achieved using time-domain-encoded VMM design. We have performed rigorous simulations of such a circuit, taking into account non-idealities such as drain-induced barrier lowering, capacitive coupling, charge injection, parasitics, process variations, and noise. Our results, for example, show that the 4-bit VMM of 200-element vectors, using the commercially available 64-layer gate-all-around macaroni-type 3D-NAND memory blocks designed in the 55-nm technology node, may provide an unprecedented area efficiency of 0.14 µm2/byte and energy efficiency of ∼11 fJ/Op, including the input/output and other peripheral circuitry overheads.
Keywords: Mixed-signal VMM, 3D-NAND Flash Memory, Time domain Encoding Scheme.
