PROM vs. PAL architecture comparison Evaluate the statement: “The architecture of a PAL differs slightly from that of a PROM.” Consider the core array structures and which planes are programmable.

Introduction / Context:
Programmable logic families vary primarily by which logic planes (AND/OR) are programmable and by how product terms are organized. PROM and PAL represent different architectural choices that lead to different use cases and compile strategies.

Given Data / Assumptions:

• PROM devices generally provide a fixed AND plane (decoder) with a programmable OR plane (fuses determine which minterms feed an output).
• PAL devices typically implement a programmable AND plane feeding a fixed OR plane (product terms are selectively created and then summed in fixed groupings).
• GALs generalize PAL behavior with reprogrammable technology.

Concept / Approach:
The essential distinction is which plane is programmable. This difference affects how equations are minimized and how many product terms per output are available. While the phrase “differs slightly” understates the practical differences, it remains true that the architecture differs (at least in the programmable plane).

Step-by-Step Solution:

Verification / Alternative check:
Any introductory PLD text includes array diagrams contrasting PROM and PAL structures and the programmable plane.

Why Other Options Are Wrong:
“Incorrect” would assert these devices share the same architecture, which they do not.

Common Pitfalls:
Assuming PROMs can naturally implement wide sum-of-products with constrained product-term allocation as PALs do; their resource trade-offs differ.

Final Answer:
Correct