Standard and Specialty Logic

Standard and Specialty Logic are devices that fit into two distinct categories of logic device. Standard Logic devices are generic logic functions that comply with the original classic 7400 series logic family. This was a series of transistor to transistor logic (TTL) that included devices with functions like logic gates, flip-flops, counters, arithmetic logic units (ALUs) and bus transceivers. As time progressed and technology advanced, new faster, high performance, voltage or even different technology (for example CMOS) devices became available that were in the same footprint and had the same function as the original devices. This allowed devices to have consistent pin outs and in some cases enabled newer devices to replace the old without a re-layout of the PCB. These alternative devices took on different family names like the CMOS 4000 Series and had similar naming conventions to enable designers to recognize the logic functionality and pinout.

Specialty logic devices include a wide variety of components that are typically application specific in nature and cannot be viewed as generic devices in a similar way to the 7400 Series. Such devices may support functionality not included in the original 7400 Series. Examples of this include special technology conversions, level shifters, Digital Phase Locked Loop Filters, Digital Delay Elements, Differential Receivers, and Transmitters.