Compound logic gates (sometimes Complex logic gate) are simple devices that function like a few basic logic gates combined. Typically made from a few levels of logic, those gates can be used in optimizing various circuits in terms of area and transistors, yielding better performance. This is especially true when development is restricted to a vendor's standard cell library. While some are rarely used by actual logic designers (simply due to their complexity), those gates are often used by optimization programs are able to make efficient use of such gates.
Although there are gate symbols from any standardization body, this article includes the symbols most commonly used to represent such gates on schematic diagrams. In most standard cell libraries, those gates are represented as a simple square, must like flip-flops and latches.
Below are common compound logic gates:
- Main article: AND-OR-Invert
- Main article: OR-AND-Invert
- Main article: Transmission Gate