Programmable Logic Devices (PLDs) — scope and limits: PLDs simplify digital design, but can a single PLD reasonably satisfy all possible requirements of complex digital circuitry, or are there cases that require larger devices (for example, FPGAs/ASICs) or multiple chips?

Introduction / Context:Programmable Logic Devices (PLDs) — including SPLDs (PAL/GAL) and CPLDs — let designers implement custom logic quickly. However, highly complex systems often exceed the capacity, speed, or I/O resources of a single PLD. Understanding when PLDs suffice and when designs demand FPGAs, ASICs, or multiple devices is a key architectural judgment in digital electronics.

Given Data / Assumptions:

• PLDs offer a finite count of macrocells/product terms and limited I/O pins.
• Large systems may require deep memory blocks, high-speed DSP, or thousands of registers.
• Performance, power, and cost constraints must be met simultaneously.

Concept / Approach:The core idea is resource matching. A device must have enough logic, routing, and I/O to realize the required state machines, datapaths, and interfaces. If a single PLD cannot provide sufficient product terms, flip-flops, or timing margins, engineers select larger devices (CPLD → FPGA) or partition across multiple parts. Some functions (for example, very wide multipliers or embedded RAM) might be unavailable in many PLDs, making an FPGA or ASIC the practical choice.

Step-by-Step Solution:

Verification / Alternative check:Create a quick synthesis targeting the intended PLD family and review resource utilization and timing reports. If utilization nears 100% or timing slack is negative, the single-PLD solution is inadequate.

Why Other Options Are Wrong:

Common Pitfalls:Overfilling a device and missing timing; underestimating I/O count; ignoring clocking and metastability; overlooking in-system programmability or field updates.

Final Answer:Correct