Advantages and Disadvantages of Fixed Logic Versus Programmable Logic

Advantages and Disadvantages:

1.           If we want to build a fixed logic device to perform a certain specific function, the time required from design to the final stage when the manufactured device is actually available for use could easily be several months to a year or so. PLD-based design requires much less time from design cycle to production run.

2.           In the case of fixed logic devices, the process of design validation followed by incorporation of changes, if any, involves substantial nonrecurring engineering (NRE) costs, which leads to an enhanced cost of the initial prototype device. In the case of PLDs, inexpensive software tools can be used for quick validation of designs. The programmable feature of these devices allows quick incorporation of changes and also a quick testing of the device in an actual application environment.

In this case, the device used for prototyping is the same as the one that would qualify for use in the end equipment.

3. In the case of programmable logic devices, users can change the circuit as often as they want to until the design operates to their satisfaction. PLDs offer to the users much more flexibility during the design cycle. Design iterations are nothing but changes to the programming file.

4. Fixed logic devices have an edge for large-volume applications as they can be mass produced more economically. They are also the preferred choice in applications requiring the highest performance level.