A CMOS analog circuit for Gaussian functions

A simple CMOS analog circuit that performs the Gaussian function for classification applications is introduced. Combining the exponential characteristics of MOS transistors in weak inversion and the square characteristics in strong inversion the function is built. Design constraints and mismatch effects are discussed, as well as the layout optimization. The circuit has been designed in a SOI technology and manufactured. Good experimental results are obtained which shows that the circuit is suitable to be included as a building block of an IC to perform classification tasks or other possible applications.