Programmable logic array

A programmable logic array (PLA) is a kind of programmable logic device used to implement combinational logic circuits. The PLA has a set of programmable AND gate planes, which link to a set of programmable OR gate planes, which can then be conditionally complemented to produce an output. It has 2^N AND gates for N input variables, and for M outputs from the PLA, there should be M OR gates, each with programmable inputs from all of the AND gates. This layout allows for many logic functions to be synthesized in the sum of products canonical forms.

PLAs differ from programmable array logic devices (PALs and GALs) in that both the AND and OR gate planes are not programmable. PAL has programmable AND gates but fixed OR gates ^{[clarification needed]}