A multiple input differential amplifier based on charge sharing on a floating-gate MOSFET

Abstract

The loseless property of an MOS floating gate is exploited to implement exact summing operations in the charge domain. Loseless charge sharing in such structures yields circuits with potential applications as building blocks for analog signal processing. Large signal as well as small signal models of floating-gate transistors are presented for both above-threshold and subthreshold regions. Experimental data from fabricated devices in a 2 micron double poly, n-well process are in good agreement with the models. A canonical structure, the Multiple Input Floating-gate Differential Amplifier is proposed and its use in different circuit configurations demonstrated. Experimental data from a multiple differential input operational amplifier are presented. Limitations of the proposed circuits are also discussed. © 1994 Kluwer Academic Publishers.