Double Density PLA Using Polysilicon Technology
Original Publication Date: 1979-Jul-01
Included in the Prior Art Database: 2005-Feb-20
In PLAs (programmable logic arrays) and other array structures, significant increase in density can be achieved by creating the arrays as AND or NAND structures rather than as the NOR structures presently in use. The increase in density results from the fact that the array outputs can be spaced one diffusion distance apart rather than two diffusion distances apart. In standard array structures, the output diffusions are separated from each other by ground diffusions. In the proposed structure, those ground diffusions are eliminated. The figure shows how the AND structure is formed.