Digital Electronics: Principles, Devices and Applications

Programmable Logic Devices 313A B C DProgrammable OR-arrayProgrammable AND-arrayY1 Y2 Y3 Y4Figure 9.11Internal architecture of a PLA device.A, B, C, DInputsTrueComp.44AND8x8Array8x4ORArrayOutputsFigure 9.12Alternative representation of PLA architecture.While implementing a given Boolean function with a PLA, it is important that each expression issimplified to a minimum number of product terms which would minimize the number of AND gatesrequired for the purpose. Since all input variables are available to different AND gates, simplificationof Boolean functions to reduce the number of literals in various product terms is not important. In fact,