A combinational circuit is a network of logic gates with no feedback loops or memory elements. Its output is calculated instantly from the current input values, subject only to the propagation delay of the gates. Common examples include adders, multiplexers, and decoders, which perform boolean algebra operations without relying on a clock or previous states.
We can implement this address decoder purely as a combinational circuit to save logic gates.
Related terms
Combinational logic
A type of digital logic where outputs are determined entirely by the present combination of inputs.
Multiplexer
A digital switch that routes one of several input signals to a single output line based on control signals.
Full adder
A digital logic circuit that adds three single-bit binary numbers and outputs a sum and a carry bit.