Design Of Active Analog Filter Based On Floating-gate Technology

The basic concept and theory about analog filter that was invented about 100 years ago is very mature today. Researchers are more interested in realizing analog filter than the others of it. Because of the high-speed advance in integrate circuit technology, traditional methods to realize analog filter are becoming more and more unfit for the desire of miniaturizing the devices. As a kind of new and high-functionality technology, floating-gate technology has been paid much attention to recently. The great potential of using this technology to designing analog filter has absorbed many researchers.Some basic theories and classical methods of analog filter are introduced in this paper before discussing how to use the floating-gate technology to realize analog filter. These theories and methods are presented as a base for the latter research. Some conception and principle about floating-gate technology and two typical devices—single-input gate FGMOS transistor (floating-gate MOS transistor) and multi-input gates FGMOS transistor that are both based on floating-gate technology are presented detailed in this paper. By the way, the multi-input gates FGMOS transistor is also called neuron MOS transistor. A new method to realize analog filter that is based on neuron MOS transistor is also given in the paper. Compare with the classical realizing methods, the new method has many advantages such as high-integration density, perfect-reliability and so on.How to build the equivalent circuit model of neuron MOS transistor and how to realize the analog filter with it is emphasized in the paper. Because neuron MOS transistor is a kind of new device, PSpice simulate software can't process it directly. The PSpice equivalent circuit model of neuron MOS transistor is completed by the ABM function of the PSpice simulate software. The efficiency and accuracy of this model is verified by plenty of experiments. An operational amplifier, but an analog filter, has been designed directly by neuron MOS transistor, which possesses not only the common characters that all the common O.A. (operational amplifier) does but also some special advantages such as small-space, high-integration density, sole negative supply source and so on. Finally according to the classical theories of RC active analog filter, a new active analog filter is realized based on the neuron MOS transistor O.A. Lots of results of simulation show that this design method is feasible.