Sensitivity study and improvements on a nonlinear resistive-type neuron circuit

This paper presents a generalized circuit for a nonlinear resistive-type neuron that implements a saturating function by combining nonlinear characteristics of NMOS and PMOS transistors. A particular circuit realization is studied in detail. Both single-ended and differential neuron circuits are presented. Characteristic variations are shown to be inherently small based on analysis, simulation and measurements. Variations are measured both across a chip and among several fabricated dies. On-chip variations, although small, are further reduced via a distributed-neuron realization that utilizes a parallel combination of identical compact subneurons. Submicron 0.8 μm and 0.35 μm designs are compared with a conservative 1.2 μm CMOS implementation