Efficient Lookup Table Modules for User-Programmable Integrated Circuits

摘要

A 4-input lookup table module including eight first-rank 2-input multiplexers, four second-rank multiplexers, two third-rank multiplexers, and one fourth-rank multiplexer, the first-rank through fourth-rank multiplexers forming a tree structure. A select input of the fourth-rank multiplexer is coupled to a first input node. Select inputs of the third-rank multiplexers are coupled to a second input node. Select inputs of a first and a second adjacent ones of the second rank 2-input multiplexers are electrically isolated from select inputs of a third and a fourth adjacent ones of the second rank 2-input multiplexers. Select inputs of a first through a fourth adjacent ones of the first rank 2-input multiplexers are electrically isolated from select inputs of a fifth through an eighth adjacent ones of the first rank 2-input multiplexers.