Programmable logic array (PLA)

For the mapping of an irregular combinational logic functions into fine regular function PLA is used. Programmable logic array provides an organized way of implementing multiple output functions in sum of products (SOP) form. It includes a programmable tw0-level AND/OR structure. Practical observation is that for a TTL-based system designer, a range of ‘off-the shelf’ PLAs are available. These custom PLAs are programmed during the VLSI design process. A PLA circuit is readily turned into a stick diagram and then to mask layout form.