PLA vs. PAL — Key architectural difference Choose the correct statement comparing the programmability of the AND/OR planes in PLAs and PALs.

Introduction / Context:Both PLAs (Programmable Logic Arrays) and PALs (Programmable Array Logic) implement sum-of-products functions. Their principal architectural difference lies in which logic planes are programmable, a distinction that influences flexibility, density, and performance.

Given Data / Assumptions:

• PLAs: both AND and OR arrays are programmable (max flexibility).
• PALs: programmable AND array feeding a fixed OR array (faster, simpler).
• Both implement logic using product terms summed (ORed) into outputs.

Concept / Approach:Compare the programmability of planes directly. If both planes are programmable, that is a PLA. If only the AND plane is programmable, with a fixed OR structure, that is a PAL. This standard textbook distinction resolves the question.

Step-by-Step Solution:Identify PLA: AND plane programmable; OR plane programmable.Identify PAL: AND plane programmable; OR plane fixed.Map to answer choices → option stating PLA has both programmable and PAL has only AND programmable is correct.Reject alternative claims that reverse or conflate the two.

Verification / Alternative check:Datasheets and academic references consistently describe PLAs with full two-plane programmability and PALs with a single programmable plane.

Why Other Options Are Wrong:

• Options B, C, D contradict accepted architectural definitions or make unfounded generalizations.

Common Pitfalls:Assuming more programmability always equals better performance; PALs traded flexibility for speed and simplicity in many use cases.

Final Answer:The PLA has a programmable OR plane and a programmable AND plane, while the PAL only has a programmable AND plane.